Renewable micro-generation of heat and electricity—Reviewon common and missing socio-technical configurations

Jouni K. Juntunen a,n, Sampsa Hyysalo b

a Aalto University School of Business, PO Box 21230, 00076 Aalto, Finlandb Aalto University School of Arts, Design and Architecture, PO Box 31000, 00076 Aalto, Finland

a r t i c l e i n f o

Article history:Received 24 November 2013Received in revised form11 December 2014Accepted 3 April 2015Available online 19 May 2015

Keywords:Renewable energyMicro-generationDecentralized energy productionSocio-technical configurationBusiness modelCommunity energy

a b s t r a c t

Awidespread adoption of distributed generation (DG) technologies in energy systems can play a key rolein creating clean, reliable energy and support the targets of emission reduction. A transition from currentmodes of production to a significant deployment of renewable energy technologies can fundamentallyaffect the structure of the industry and change the way energy is produced, transmitted and sold. Thecurrent paper provides an extended review of the socio-technical configurations of micro-generationbased on journal publications and reports during the 21st century. The paper analyses currently existingand missing configurations and discusses technology and policy implications to support proliferation ofmicro-generation technology and local energy production from renewable sources. The potential for newconfigurations can be found particularly in heat producing micro-generation with solar heat, heatpumps, and biomass. Developing further the operations and maintenance of distributed generationtechnologies and business models appears an area that calls for further innovation, and correspondinginnovation policy measures. Third party service and community-driven deployment models can aide theproliferation of distributed generation and further innovation therein, justifying the introduction offeed-in-tariffs to attract such models during their early diffusion.

& 2015 Elsevier Ltd. All rights reserved.

Contents

1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8581.1. Concept of micro-generation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 858

2. Analytical framework . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8592.1. Organizing around micro-generation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8592.2. Methodology and procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 859

3. Existing configurations—Technical and non-technical aspects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8603.1. Technologies of micro-generation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8603.2. Ownership and financing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8603.3. Operation and management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8613.4. Distribution of energy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8633.5. Summary on existing socio-technical configurations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 865

4. Missing socio-technical configurations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8664.1. Technological limitations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8664.2. Service-based models and limited market demand . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8674.3. Opportunities with community energy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 867

5. Policy implications of missing configurations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 867

Contents lists available at ScienceDirect

journal homepage: www.elsevier.com/locate/rser

Renewable and Sustainable Energy Reviews

http://dx.doi.org/10.1016/j.rser.2015.04.0401364-0321/& 2015 Elsevier Ltd. All rights reserved.

n Corresponding author. Tel.: þ358 405062114.E-mail address: Jouni.juntunen@aalto.fi (J.K. Juntunen).

Renewable and Sustainable Energy Reviews 49 (2015) 857–870

6. Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 868Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 869References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 869

1. Introduction

Decentralized energy production based on renewable sources isa commonly presented vision and solution for future energy needs[1]. The exponential growth in distributed photovoltaic installa-tions has been accompanied with a widening range of theirdeployment models. Other decentralized renewables appear tofeature fewer alternatives to the deployment models. As a fullerrange of available models could also help the proliferation of thesetechnologies, it is worth examining whether these technologieshave hitherto been deployed in a more limited array of models,and if so, are these limitations inherent or could they be subjectedto targeted measures for innovation and for energy policy. After ananalytic review it appears that only some of the limitations areinherent and there is room for development.

According to recent research, distributed generation (DG)technologies may yield significant benefits in terms of energyefficiency and reduced carbon emission. This is due to the fact thatDG combines geographically dispersed decentralized generationfrom preferably renewable sources [1,2]. DG can reduce losses inenergy distribution [3], improve energy security by producingenergy close to the point of consumption [4], facilitate an increaseof energy services in remote rural areas in developing countries[5–9] and consequently it may foster social equity by providingenergy services and capacity for households and villages to reduceextreme poverty and advance standards of living [10]. In addition,DG from local renewable sources, also called micro-generation,can reduce dependencies on foreign energy sources.

Energy technologies are not just material objects, they also canbe seen as embedded components of socio-technical systems—inwhich energy final users, producers, infrastructures, regulators,and other intermediaries are all embroiled [11–14]. A transitionfrom current modes of production to significant deployment ofrenewable energy technologies will fundamentally affect thestructure of the energy industry and change the way that energyis produced, transmitted, and sold [15–19].

Technologies emerge through active development, linkages,and the alignment of various heterogeneous, social, and technicalelements into working configurations [20]. Science and technologystudies (STS) have revealed a wide variety of different “configura-tions” of renewable energy technologies and the elements of socialorganization involved in their deployment. Socio-technical con-figurations comprise assemblies of technological components, andnon-technological components such as human factors. A config-uration can be seen as an unique assembly of components built upto meet the particular requirements of organization [21,22]. Theseorganizational interacting mechanisms around energy technologyinclude dimensions such as ownership, management, operation,and infrastructure [11].

Another stream of literature and research has been interestedin value chain(s) in the renewable energy business and deploy-ment models [4]. Especially the issue of utilities’ business modelsfor renewable energy has been addressed by a number of recentreports [18,23–26] and academic studies [27].

Both streams of literature show how organizing a micro-generation is in constant change and new configurations areemerging. Production of renewable energy is becoming multi-faceted and clear demarcation lines between centralized anddecentralized, grid-connected and off-grid, and producer and

consumer, are increasingly becoming blurred. New configurationsconsist of different sizes of networks that underpin the energyconsumption of consumers and communities [2].

This paper is interested in the deployment of micro-generationtechnologies. The article departs from the framework introduced byWalker and Cass [11] in 2007, and adapts it to discuss renewablemicro-generation, the covering technologies, ownership, financing,production, and the distribution of energy. Our contribution istwofold. First, we review current academic literature complemen-ted with up to date documents to reveal existing socio-technicalconfigurations of renewable micro-generation technologies. Second,we analyze technological and organizational combinations thatcreate configurations which remain unrealized or marginalized cf.[28]. Our findings offer insight for policy makers in the field ofenergy, and help companies and user groups to understand variousopportunities and current restrictions when enhancing the diffu-sion of micro-generation technologies and scaling up local renew-able energy production. Such insight and opportunities have beenhitherto discussed mostly with regard to the solar photovoltaics(PV) domain only, and we expand on this.

The article begins with opening up the concept of decentralizedgeneration, micro-generation, and the methodological approach thatwill be used in this study. We then describe different types of socio-technical configurations taking place in the micro-generation of heatand electricity. In Section 4 we analyze marginal and missingconfigurations and the reasons that hinder the emergence of certainconfigurations. Finally, we discuss innovation and energy policyimplications and how these could speed up the proliferation ofmicro-generation technologies.

1.1. Concept of micro-generation

Decentralized or distributed energy supply refers to the gen-eration of energy close to the place where energy is used. It canmean a range of generator sizes; from residential households tocommunity or district-level [3]. Micro-generation is the term givento small-scale local energy generation, and it has various defini-tions, which vary from country to country. The key characteristicsof these definitions are that micro-generation occurs at a localscale, it can include both the generation of heat or electricity orboth, and it generates small amounts of energy compared tocentralized plants. Furthermore, there is often a requirement ofenvironmental friendliness in the production. For example in theUK, the Energy Act section 82 defines micro-generation as gen-erating plant with a capacity of less than 50 kW. Most residentialinstallations are in the range of 2.5–3 kWpcs [3,27]. In the case ofelectricity, it can be for the sole use of the building’s occupants orit can feed the National Grid.

Various renewable energy sources are used for micro-generation.These include solar, wind, biomass power (e.g. wood, wood pellet,bio waste), and the utilization of outdoor and ground source heat.Hydropower can also be built on a small-scale, the capacity definedas small, mini or micro-hydropower [29]. It is noteworthy that micro-hydropower definitions of size and capacity differ from other sources,and a hydropower plant with the capacity of between 50 kW and10 MW is still considered as a micro-hydropower [30,31]. Definitionsof small-scale Waste to Energy (WTE) systems have some variations.There are studies [32,33] that define small-scale WTE is as capacity

J.K. Juntunen, S. Hyysalo / Renewable and Sustainable Energy Reviews 49 (2015) 857–870858

below 100,000 t of waste per year, which equal to 33–67 MWthermal capacity. In some other studies [34,35], a small-scale WTEdefinition is more inline with typical micro-generation definitions i.e.below 50 kW output.

In this article we focus on the above common technologies thatare available as established commercial systems in many markets,even if not necessarily globally.

2. Analytical framework

2.1. Organizing around micro-generation

Different types of deployment models of micro-generationhave received attention in studies of energy policy. These modelsinclude business model like considerations, but also take intoaccount different ways of organizing the production, such ascommunity energy [4]. As micro-generation is gaining momen-tum, new types of actors and ways of organizing around micro-generation are emerging.

In earlier studies, by Walker and Cass [11] and Sauter [36], theauthors make a division between technology and social and infra-structural actors in their conceptualizations of socio-technical con-figurations of the renewable generation. Technologies generateusable energy in the form of heat or electricity. The social andinfrastructural actors utilize the technologies. These actors take careof functions such as generation, distribution network, ownership,operation, management, service, consumer–supplier relationshipand supply chain. How the energy technology is used also includesconsiderations of learning, skills and the function for which theenergy is used. Walker and Cass examine all sizes of renewableenergy production and list five implementation ‘modes’: publicutility, private supplier, household, community and business [11].These modes especially reflect the ownership dimension of produc-tion. Walker and Cass [11] framework is the most comprehensiveattempt to analyze socio-technical configurations of renewableenergy productions. Thus it has been taken as starting point in thisstudy to create a practical tool for analyzing micro-generationtechnologies. For the purposes of the present study, the Walkerand Cass framework has been adapted for what can be analyzedregarding the variety of socio-technical configurations in micro-generation reported in reliable published sources as of 2014. Thishas required altering, further focusing and developing the earliermodel in the following aspects;1

� Nuanced examinations on function and service have been leftout of this model. Function and service is electricity or heat isalways produced primarily for local consumption and some-times also fed to grid. Questions of final energy consumptionpurposes such as comfort, warmth, visibility, or mobility wouldrequire further research that goes beyond literature review ofpresently available information.

� Micro-generation implementation model variations are morelimited. In practice three implementation modes takes place,namely household, community, and business (aka company-driven, utility or third party business) [38].

� Locality can be seen as a key dimension in conceptualizing micro-generation and has been added as second dimension to our

analysis framework. Dimensions of ownership and financing,operation and maintenance, and distribution of energy can beviewed from the point of locality; i.e. what is the physical andinstitutional distance between the local site of production and thesite of service consumption [11]. The degree of locality depictsenergy autonomy or self-sufficiency, which is the ability of anenergy system to function based on own local energy generation,storage, and distribution systems without the need of externalsupport [39]. The proximity levels (user/household, community,business) follow widely used approach in the literature. Anabstraction level of analysis has been put to a position that canbe answered and filled by a rigorous literature review.

The socio-technical configurations framework for micro-generationis presented in Fig. 1. The vertical axis presents increasing locality inthree steps, and horizontally the figure is divided in to three separatedimensions; ownership and finance, management and operation, anddistribution as described above.

2.2. Methodology and procedure

In this paper, our analysis follows the socio-technical config-urations framework for micro-generation. The analysis of socio-technical configurations can make visible both the options oforganizing around renewable micro-generation and the valuenetwork around local small-scale energy production.

In the study of configurations, the micro-generation of energyis scrutinized without particular actors’ viewpoints (corporate,community, or user/consumer/citizen). How actors take differentpositions in a socio-technical network within which they operatethen becomes interesting. The actors include individual users,communities, and corporates2. The configuration depictions showhow different dimension can be configured in multiple ways.

The concept of shared value creation has received limited atten-tion in traditional energy business model analysis, which is based ona top-down hierarchy from generation to distribution and the finaluse of energy. A value chain perspective is presented in Fig. 2. In thevalue chain, actors follow each other in the marketplace. However,decentralized energy systems can be characterized as value networkscf. [40]. To understand the roles and engagements of actors withinthe energy system requires a multidimensional conceptualization[11]. A configuration can be seen as the conceptualization of anetwork wherein actors take a position, connect to each other, addvalue, create and share knowledge, and make transactions.

Close Proximity

Medium Proximity

Distant Proximity

Ownershipand finance

Management and operation

Distribution of energy

Utility and 3rd party driven models

Community driven models

User driven models

universal distribution grid connected

micro-grids district heating networks

off-grid locally produced and

consumed

Fig. 1. The socio-technical framework for micro-generation: Non-technical dimen-sions and proximity between point of generation and energy use (adapted from[11]).

1 Bracken et al. propose “environmental dimension” to be added to Walker andCass original model to take into account ecological impacts such as biodiversity[37]. For the purposes of this study inclusion of environmental dimension wouldcomplicate the analysis beyond what can be achieved through literature review ofmaterials available to date. Taking into account various aspects of ecologicalimpacts both locally and globally (in supply chain) of technologies would arguablyrequire separate study focusing to this dimension with each micro-generationtechnology examined.

2 In the network of actors policy makers also play a role, especially in theformulation of (dominant) configurations. However, if production-based support-ing mechanisms such as FIT are not used, the role of regulation may be ratherlimited in a socio-technical configuration that is running a daily operation.

J.K. Juntunen, S. Hyysalo / Renewable and Sustainable Energy Reviews 49 (2015) 857–870 859

Our analysis is based on two separate information sources or sets.There has been increasing interest in research to address differentaspects of micro-generation technology and business and develop-ment models. Thus, a logical point of departure in this study was toreview recent (from 2000 to 2014) academic articles on micro-generation in the areas of business and deployment models. Thesemodels explain the key characteristics of organizing around thetechnology, define points of control, and help to construct depictionsof socio-technical configurations that have already been recognizedin research and academic literature. The literature review includes anextensive set of empirical studies both from the developing countriesand from developed industrial countries.

However, renewable micro-generation is an emerging area:academic literature is scant and most of it is too constricted tothoroughly address the issue. Moreover, many of the models areemerging as we speak, and academic publications appear to lagbehind the new configurations and value networks that areemerging. Thus, other sources available on the Internet wereconsulted in order to gather further information relevant to theanalysis and to fill the gaps in academic publications. The addi-tional material includes reports, documents, company pages, andmaterial from cleantech news sites.

This study has two main research questions:

1. What kind of socio-technical configurations have been estab-lished around renewable micro-generation technologies?

2. What are the missing configurations and the underlyinglimitations and barriers affecting the absence of certainconfigurations?

The literature review began by searching with 12 relevantkeywords4 from two main academic search services. First, a fulltext search was carried out in Ebsco for Financial Times 45 listbusiness journals. Second, both Ebsco and Sciverse ScienceDirectfull text searches were carried out for a wider range of business,economics, technology, and energy specific journals. The initial

round resulted in 1246 articles from 171 journals. The duplicates ofarticles, conference proceedings, non English journals and outsideof scope tech journals (e.g. hydrogen or fuel cells technology) wereremoved, which reduced the number of journals to 154 with 925unique articles. Finally, based on an examination of abstracts5, 101academic publications were found that were relevant for thisstudy, of which 23 articles had a significant contribution in thearea of business or deployment models (discussed in Section 3.2).

3. Existing configurations—Technical and non-technicalaspects

3.1. Technologies of micro-generation

Micro-generation technologies are small-scale systems that gen-erate energy in usable form from heat or electricity or both. In thehistorical perspective, the oldest form of micro-generation is woodburning fireplaces, but available technology alternatives, productmodels and solutions are steadily increasing. To give an overviewof commonly6 used technologies, Table 1 presents energy sourcesand technological alternatives of micro-generation. Micro-generationis a technology that converts a source energy to a form that can beutilized for certain functions, which, for example, can be warmth orcomfort [11].

3.2. Ownership and financing

Various legal and financial models of ownership have beenadopted for micro-generation. One hundred % public ownership isnot common, but public involvement in supporting schemes iswidely present. A whole range of combinations between publicand private ownership exists: projects can be community owned,or may be developed under co-ownership arrangements (e.g.public–private sector partnerships [43]). Projects can involve theownership of energy generation that is grid-connected or off-grid,or can combine the locally owned production and consumption ofenergy (e.g. where heat is generated for local use for one or severalbuildings) [44].

Fig. 2. Value chain perspective of micro-generation. The example case of solar (PV) technology. Adapted from [41,18].3 Distribution of electricity is not included in the figure.Other electricity generating technologies follow the main features of the solar PV value chain. In heat production, the supply chain of energy source material creates anadditional dimension to the value chain.

3 Distribution of electricity is not included in the figure. Other electricitygenerating technologies follow the main features of the solar PV value chain. Inheat production, the supply chain of energy source material creates an additionaldimension to the value chain.

4 Community energy, decentralized energy (decentralised energy), decentra-lized power (decentralised power), dispersed generation, distributed energy,micro-generation (microgeneration), rooftop solar, solar home system, solar ANDfee-for-service, solar AND lease, third party solar, waste to energy.

5 The abstract addressed topics of business and deployment models, financing,operations, management, distribution of heat or electricity, or storage of energy.

6 Emerging technologies (e.g. micro-CHP and fuel cells) without significantmarket adaptation have not been listed.

J.K. Juntunen, S. Hyysalo / Renewable and Sustainable Energy Reviews 49 (2015) 857–870860

Ownership issues are inseparable from organizing the finan-cing for energy production. There is an extensive literature onfinancial subsidies for energy projects. Through the use of sub-sidies, government aims to lower the cost of energy provisioneither through incentives for energy generation or price reduc-tions to consumers. In recent research, the main interest has beento study energy generation incentives, namely feed in tariffs (FIT),to enhance the diffusion of the technology [45,46]7. Table 2presents an overview of recent literature on business, financingand deployment models.

Ownership models can be divided in to different categories bylooking at the distances from operational technology and energyproduction site to an actor or an institution that holds the own-ership of the production equipment. From this viewpoint owner-ship can be divided in to a local ownership at site of theproduction or to ownership outside the site of production. Bothends include various kinds of models. Friebe et al. [51] examinesolar PV technology and divide options along the lines of cash,credit, leasing, and fee-for-service. Based on the literature review,business and ownership models of solar PV has been most widelystudied among micro-generation technologies. The existing mod-els are also most diverse in solar PV technology.

However, similar models may also be applied, in principle, toother micro-generation technologies, but certain technology char-acteristics do set limits and hindrances to this, which we willdiscuss later. The traditional ownership model is where houseowners, or similar, own the production unit and use upfront cashor credit (e.g. home-equity loan) to purchase equipment8. Both ofthese options are popular in the developed countries. In regardscredit based model in the developing country context, micro-finance has been used (especially with biogas based generation[57,66]).

When the ownership of production is outside of the productionsite, third party financing is used. Third party financing models i.e.service-based models include both Power Purchase Agreement(PPA) and lease [52]. There are no clear-cut definitions andimplementations have some variation, and models can also bemixed and have various local marketing terms. For example, solarPV lease can be called “rent-a-roof” and PPA as fee-for-service,

which can be marketed as “free solar on your roof” [67]. Fee-for-service and lease customers have different payment structures.With a lease consumer pays monthly fee, which is not tied to levelof production, and with a fee-for-service the payment can be fixedor based on variable production. The details of third party finan-cing can vary, e.g. a lease contract can allow the consumer topurchase the system over a certain period defined by the initialequipment owner. The homeowner can feed an oversupply ofelectricity back to the grid and sell electricity to an electricityservice provider. Third party financing has become the dominantform of financing for domestic solar PV in the U.S. [52].

In the developing countries, the fee-for-service model isreceiving increased attention. Next to all of the studies of fee-for-service focus on these markets. Using micro-credit for buildingnew energy capacity, or implementing a fee-for-service utilitymodel, is now considered as two desirable options to create adynamic self-sustained market for solar home systems [55].Donation models [10,58] in which the technology is transferredto the community as a gift is hardly in practice in the mostdeveloping countries these days [9]. The donation logic is dis-continuous, by nature, which makes it hard to succeed in along run.

On the other hand, in developed countries with FIT programs,PPA (rent-a-roof) are gaining momentum. Third party companiescan lease the equipment, and large utilities have entered themarket and provide DG technology to commercial users andprivate consumers [63].

In summary, while DG is growing, and new types of businessmodels are entering the field, the field includes a range of differentmodels of financing and ownership [52].

3.3. Operation and management

In the operation and management configuration, interest is onwho manages, controls and maintains the hardware, and how isthis organized [11]. Ownership of micro-generation equipmentand control of operation and management are typically tightlycoupled, thus ownership has a high influence on socio-technicalconfigurations. To keep technology operating and energy outputhigh is primarily the owner’s responsibility. However, ownershipand operations can be also separated via outsourcing [49],whereby ownership is purely a control and financing issue, with-out material responsibilities.

Feasible operation and management configurations are highlydefined by the operation needs of the technology. The operationneeds vary significantly from one micro-generation technology toanother. While electricity generation from solar requires relatively

Table 1Common micro-generation technologies by source and function. Adapted from [1,31,42].

Energy source Energy technology Output power type

Hydro power Small hydro-turbines ElectricityWind Micro-wind power ElectricitySolar Solar PV ElectricitySolar Solar thermal collector Heat (water)Solar Solar air collector Heat (air)Biomass: wood Fireplaces Heat (air or water)Biomass: wood Wood burning boiler Heat (water)Biomass: wood pellet Wood pellet boiler Heat (water)Biomass: bio waste, e.g. straw Small-scale combustion Heat (water), electricity, CHPBiomass: bio waste Gasification Heat (air/water), electricity, CHPSolid waste Thermolysis Heat (water)Outdoor air heat (þelectricity) Air source heat pump Heat (air)Outdoor air heat (þelectricity) Air to water heat pump Heat (water)Ground heat (þelectricity) Ground source heat pump Heat (water)Indoor air heat (þelectricity) Exhaust air heat pump Heat (air)

7 Due to the complexity and the set of issues involved, it is not possible toinclude public policy support mechanisms, such as subsidies and regulations, in theanalysis of this paper.

8 This basic model has been called also as “dealer model. Cf. Sustainability—Business Models for Rural Electrification (Source.: The ACP-EU Energy Facilityhttp://capacity4dev.ec.europa.eu/system/files/file/23/04/2012_-_1736/sustainability_ruralelectrification.pdf, accessed Nov 27 2014.)

J.K. Juntunen, S. Hyysalo / Renewable and Sustainable Energy Reviews 49 (2015) 857–870 861

Table 2Literature review of academic articles on micro-generation business, finance and deployment model and socio-technical configurations.

Author(s)/year ofpublication

Publication name Journal Business or deployment models covered Type/empiricalstudy area orcountry ifapplicable

Technologiesincluded toempirical work

Boon andDieperink[47]

Local civil society based renewable energyorganisations in the Netherlands:Exploring the factors that stimulate theiremergence and development

Energy Policy Community business models: collectiveprocurement of energy and technology,education and facilitation, delivery ofenergy, collective generation

Empirical/Netherlands

Wind, solar,biomass, geo-thermal

Derrick [48] Financing Mechanisms for renewableenergy

Renewable Energy Revolving funds, credit co-operatives,renting schemes, utility schemes/leasing,hire purchase

Conceptual Solar PV

Dornan [49] Solar-based rural electrification policydesign: The Renewable Energy ServiceCompany (RESCO) model in Fiji

Renewable Energy Fee-for-service (RESCO) Empirical study/Fiji Solar PV

Drury et al.[50]

The transformation of southernCalifornia’s residential photovoltaicsmarket through third-party ownership

Energy Policy Customer owned, Third party owned Empirical study/California, UnitedStates

Solar PV

Friebe et al.[51]

Exploring the link between products andservices in low-income markets—Evidencefrom solar home systems

Energy Policy Sales model (cash and credit), servicemodel (leasing and fee-for service)

Empirical study/several emergingand developingcountries.

Solar PV

Hess [52] Industrial fields and countervailing power:The transformation of distributed solarenergy in the United States

GlobalEnvironmentalChange

Publicly owned Utilities, PACE (DeVriesmodel), Share based models (Mt. PleasantSolar Co-op and 1BOG)

Empirical(Comparative casestudy)/UnitedStates.

Solar PV

Hujiben andVerbong[53]

Breakthrough without subsidies? PVbusiness model experiments in theNetherlands

Energy Policy Customer-owned, Community shares,Third party

Review andempirical data/Netherlands

Solar PV

Lemaire [54] Fee-for-service companies for ruralelectrification with photovoltaic systems:The case of Zambia

Energy forSustainableDevelopment

Fee-for-service (by ESCOs) Empirical study/Zambia

Solar PV

Lemaire [55] Off-grid electrification with solar homesystems: The experience of a fee-for-service concession in South Africa

Energy forSustainableDevelopment

Fee-for-service, credit (micro-credit) Empirical study/South Africa

Solar PV

Liu et al. [56] Purchasing vs. leasing: A benefit-costanalysis of residential solar PV panel use inCalifornia

Renewable Energy Leasing, Cash, Credit (home equity loan) Empirical study/US Solar PV

Mainali andSilvera [57]

Financing off-grid rural electrification:Country case Nepal

Energy Fee-for-service, leasing of energy-generating products, credit (credit fromlocal cooperatives, revolving funds, creditfrom commercial banks)

Empirical study/Nepal

Micro-hydro andsolar PV

Mainali andSilvera [9]

Renewable energy markets in ruralelectrification: Country case Nepal

Energy forSustainableDevelopment

Cash, credit, private ownership,community ownership)

Empirical study/Nepal

Micro-hydro andsolar PV

Nieuwenhoutet at. [58]

Experience with Solar Home Systems inDeveloping Countries: A Review

Progress inPhotovoltaics:Research andApplications

Donations, cash sales, consumer credit,fee-for-service,

Empirical/Developingcountries

Solar PV

Obeng andEvers [59]

Impacts of public solar PV electrificationon rural micro-enterprises: The case ofGhana

Energy forSustainableDevelopment

Fee-for-service Empirical study/Ghana

Solar PV

Okkonen andSuhonen[60]

Business models of heat entrepreneurshipin Finland.

Energy Policy Co-operative, ESCO (larger scale utilitymodels presented also)

Empirical study/Finland

Wood pellets, woodand peat

Provance et al.[61]

Institutional influences on business modelchoice by new ventures in themicrogenerated energy industry

Energy Policy Plug and play, company-driven,community micro-grid

Conceptual Generic

Rai and Sigrin[62]

Diffusion of environmentally-friendlyenergy technologies: buy versus leasedifferences in residential PV markets

EnvironmentalResearch Letters

Lease (utility), cash Empirical/UnitedStates

Solar PV

Richter [63] German utilities and distributed PV: Howto overcome barriers to business modelinnovation

Renewable Energy Utility DG, energy efficiency, distributedstorage

Empirical study/Germany

Solar PV

Sauter [36] Socio-technical implications of domesticmicrogeneration technologies in the UKelectricity system

InternationalJournal ofEnvironmentalTechnology andManagement

Plug and play, community micro-grid,company-driven (utility and new energyservice companies)

Empirical study/United Kingdom

Generic. Discussesmicro-CHP, micro-wind, solar PV.

Sauter andWatson [38]

Strategies for the Deployment of Micro-Generation: Implications for SocialAcceptance

Energy Policy Plug and play, community micro-grid,company control

Reviewþempiricaldata/UnitedKingdom

Generic

Sovacool [10] Design principles for renewable energyprograms in developing countries

Energy &EnvironmentalScience

Cash, credit, mixed finance, donationmodel, fee-for-service, leasing, ESCO

Empirical/developingcountries

Generic

J.K. Juntunen, S. Hyysalo / Renewable and Sustainable Energy Reviews 49 (2015) 857–870862

low maintenance depending on environmental conditions such assoiling rate, heat production technologies using biomass canrequire weekly (e.g. wood pellet heating) or even daily (e.g. woodheating) intervention. Fig. 3 shows how operation and mainte-nance frequency separates electricity from heat producing tech-nologies. Management and operation can be organized privately,collectively, or publicly, but viability of these options is tied to anactor’s (maintenance worker) proximity to the technology and tothe frequency of a required site visit.

3.4. Distribution of energy

Although the basic principle of micro-generation is to produceand consume energy at the same location, a distribution networkenables the transfer of energy and proximity between productionand consumption. This solid infrastructural connection is an essentialdimension in the analysis of the socio-technical configuration.

In Fig. 4, electricity distribution is used as an example todemonstrate the multitude of distribution configurations. Electri-city distribution occurs through different types of organizations,with country variations and ownership combinations. Tradition-ally the ownership of the distribution network has been tradition-ally concentrated to large organizations such as those of the state,municipality, or energy utilities. For example, in the U.S., electricitydistribution occurs through three main types of organizations—public utilities, investor owned utilities, or distribution coopera-tives [52]. These very same distribution networks are used whenmicro-generation is connected to the grid.

Social public–private partnerships or customer trusts are exam-ples of new forms of ownership used with distribution networks. InNew Zealand there is a local electricity distribution company havingthe form of a customer trust, it is owned and governed byconsumers [68]. In Germany, within the last five years over 450new energy cooperatives have emerged that are not only setting upenergy generation but also have taken an important role in runninglocal grids [69]. When local distributionwires are owned locally, theneed to regulate wholly privately owned network monopolies and

mitigate the need to regulate long term contracts for locallyproduced electricity and heat services is reduced [68].

Mini-grids and Micro-grids are smaller scale infrastructuresbetween the universal (or national) network and off-grid solu-tions. Developing mini-grids for decentralized needs is a veryimportant concept for promoting rural electrification in thedeveloping countries, since the spread of the national grid is verylow or almost absent in remote rural areas. Thus, renewable DGprovides an opportunity not only for GHG emission reductions butalso for improving the quality of life in rural communities [71].Micro-grids are increasingly important where production is basedon distributed resources, multiple electrical loads, and meters.These connected generation units can form an autonomous grid.The micro-grid can be either a parallel island from the widernational grid or connected to it. In the most common configura-tion, micro-generation inside a micro-grid is tied together with itsown distribution feeder and that micro-grid is linked to thenational grid at a single point of common coupling. In “islandedmode” there is no connection to the grid. Micro-grids can enhanceenergy security and reliability in various ways. They can reducedistribution losses, support local voltages, provide increased effi-ciency or provide stable power supply functions [72]. Micro-gridsare gaining momentum, with hundreds of individual projectsalready implemented or under construction worldwide [73].

Production and consumption of all produced energy at thesame site without connection to external networks is a specialcase. In the case of electricity, an off-grid systemworks standalone.All of the produced energy is used at the site of production and thesystem is self-reliant. Recently, off-grid electrification has beenpromoted for rural electrification as an answer to the growingenergy needs in developing countries [74]. In many developedcountries with an extensive national grid, off-grid and micro-generation has been used widely in special cases, such as onsummer houses and holiday homes. For example, in Nordiccountries in the case of remote houses there is a trade off betweennew grid extension and solar PV, which favors solar PV becauseconstantly falling panel and installations costs [75]. In terms of the

Table 2 (continued )

Author(s)/year ofpublication

Publication name Journal Business or deployment models covered Type/empiricalstudy area orcountry ifapplicable

Technologiesincluded toempirical work

Walker [64] Financing Distributed Generation Energy Engineering Appropriations, commercial bank loan,home mortgage or equity loan, lease,utility financing, chauffage (conceptual:vendor financing, bonds)

Empiricalexamples/UnitedStates

Internal combustionengine, small gasturbine, fuel cell,solar PV, micro-wind

Watson [65] Co-provision in sustainable energysystems: the case of micro-generation

Energy Policy Plug and play, company ownership,leasing

Simulation/UnitedKingdom

Solar PV and microCHP

Fig. 3. Micro-generation technology operation needs.

J.K. Juntunen, S. Hyysalo / Renewable and Sustainable Energy Reviews 49 (2015) 857–870 863

micro-generation of heat, production without external distributionand connection is even more popular. Most small-scale installa-tions are not equipped with thermal network connection to theother consumption units. Because of the losses in distributiondistance between production and consumption becomes limited.Thus current heat distribution networks connect buildings inurban area or within-community. District heating networks canbe considered as equivalent to electricity micro-grids. Both pro-vide medium proximity distribution.

The electricity infrastructure types presented in Fig. 4 providehigh-level depictions of distribution configurations. In terms ofeconomic considerations, how electricity is measured becomesinteresting with regard to how monetary transactions are carriedout and how an established market price is formed. The develop-ment and promise of a smart-grid is seeking to develop a moretransparent, two-way, distribution network, which enables small-scale production connection to the grid and participation in the

electricity market. The promise of smart-grids is that it candevelop the grid towards more sustainable system that is morereliable and more efficient in both technologically and economic-ally [76]. Peer-to-Peer networking concepts have brought modelsfrom ICT systems to community energy systems [77]. Theseconcepts have the potential to change how micro-generation inthe context of the community can be organized. Current micro-generation community energy is based on close proximity usersco-operating in energy production. In the future a communitycould be seen in a new way in the smart-grid environment, wherethe peer-to-peer approach spreads out from a close proximitycommunity to a group of remote households generating and using,and selling and buying their own energy to each other and usingthe national grid for their electricity distribution.

Energy generation from renewable sources is seldom constantover time; moreover, electricity demand is never constant. There-fore, connecting and utilizing an energy storage within a systembecomes important [78]. In addition to the stochastic natureof local production, the volatility of the market price in agrid-connected DG environment may also create a need to shiftthe consumption of produced energy.

The heat storage of hot water in boileri is a traditional andwidely used method with micro-generation of heat. Batteries havebeen used to store DG electricity and there are various technolo-gies at different stages of maturity and with a wide range oftechnical characteristics that can provide heat or electrical storage[79–84]. It is likely that several solutions will continue to competein the future due to the wide variations in possible applications[84,85].

Local energy storage is an additional new dimension in energysystems, which will also have an impact on energy usage. Userscan change their energy behavior not only based on local produc-tion or market price, but also according the local storage situation.While research of micro-generation and storage has mostlyaddressed the technical or economical aspects of local electricitystorage, less attention has been paid to heat storage [84] and thebehavioral or socio-technical aspect of storage and how it impactselectricity production and usage in daily life.

Fig. 5. Summary of socio-technical configuration in micro-hydropower. a This basicmodel has been called also as “dealer model. Cf. Sustainability – Business Modelsfor Rural Electrification (Source.: The ACP-EU Energy Facility http://capacity4dev.ec.europa.eu/system/files/file/23/04/2012-1736/sustainability_rural electrification.pdf,Accessed Nov 27. 2014.) b In a community level micro-hydropower has been usedfor rural electrification purposes [9,57]. Mini-grids, in small-sale, even for onebuilding, have been used for example to provide electrification to hospitals [71].

Generation

Transmission System

Distribution System

Energy End User

Investor-Owned Utilities

(Rural) Electric

Cooperatives

Municipal Distribution

Utilities

Bulk Power Transmission

Municipal owned

Generators

State owned Generators

Common Ownership or the Rough Equivalent Electrically Connected

(Rural) Micro Grid

Off-Grid

Energy Storage

Fig. 4. A simple electric system (Figure adapted from [19,70]).

J.K. Juntunen, S. Hyysalo / Renewable and Sustainable Energy Reviews 49 (2015) 857–870864

Local storage is not typically present in current micro-generation networking configurations because of the high priceof battery technology. Feasible options for local storage increase inconjunction with the proliferation of electric or hybrid vehiclesthat can be connected to the grid [2].

3.5. Summary on existing socio-technical configurations

We have gone through renewable micro-generation technologiesand reviewed literature on the financing, ownership, operation,maintenance, and networking aspects of energy production. InFigs. 5–9 we use the socio-technical configurations framework todepict currently existing and currently missing socio-technical con-figurations for each technology as a means to summarize ourfindings on existing configurations. Each technology has beenanalyzed separately and the existing configurations have beenmarked with a solid line. The index numbers in the figures refer to

footnotes which explain the sources. In heat distribution there arehitherto unfeasible areas, which have been marked on the pictures.

Let us use micro-hydropower as an example case to explainhow the analysis framework visualizes existing and missing socio-technical configurations. In Fig. 5 diagrams of currently existingconfigurations for the technology are summarized. For micro-hydropower we have not been able to identify third party own-ership or third party management and operation models, whichleaves these section empty. Community energy deployment hasbeen used, for example, in Nepal [9,57], and it covers all threedimensions, hence the green community energy line connectingthese areas at the community level. Cash and credit financingmodels, where the owner takes care of management and opera-tion, can be found and all possible electricity distribution formstake place in these areas (i.e. off-grid, community micro-grid, anduser owned and operated grid-connected), hence the red connect-ing lines that move from close proximity ownership and manage-ment to three extents of distribution.

The diagrams in Fig. 6 make evident that solar PV holds theleast technical and maintenance restrictions, and that it has beensubject to most business model development both as third partyand as private ownership arrangements. With regard to micro-wind, the off-grid renting schemes and leasing models remainabsent. In micro-wind the boundaries between small-scale andmedium-scale becomes easily fussy in the context of communityenergy. Community energy operations may start from small-scalegenerating units with a capacity of less than 50 kW and expandlater to medium or even large-scale, which, by definition, is nolonger micro-generation. In the community energy literature, andespecially in community energy news, the scale is rarely clearlyexplicated, which makes socio-technical configuration mapping

Fig. 6. Summary of socio-technical configuration in solar PV and micro-wind.cDifferent type of leasing models discussed in literature, which range from gridconnected to off-grid systems: Leasing model by third party companies[51,56,57,64,65], leasing by publicly owned utilities [52] and more generally utilityfinancing based on leasing [36,62–64]. dFee-for-service models are used widely[49,51,54,55,57–59]. RESCO [49], ESCO [54] and Chauffage [64] models build onsimilar basic principle where third party company owns and operates the systemsand energy output is charged based on level of production. eCommunity ownedmodels includes both credit co-operatives and community share based models[52,53]. Community micro-grids are used to share the electricity for members [61].fDerrick [48] lists grid connected utility scheme and off-grid renting schemes usedfor solar PV charging stations in South Africa and Thailand. These stations areowned by a community or entrepreneur and villagers rent batteries for rechargingat the PV charging station. gVariations of credit based models [51,57] includerevolving funds [48,57], hire purchase [48], micro-credit [55], commercial banks[57,64] and home mortgage [64]. h[9,51,56,58,62]. iBasic ownership model is to useown savings for solar PV investment [9,51,62]. PACE [52] model is based on localhousehold ownership and but the model utilizes local government bonds andcommunity tax collection in the model. jFee-for-service for micro-wind is notimplemented widely. The idea is presented for example in Sauter [36] and in Nfahand Ngundam [86] articles. k[36]. lCommunity owned micro-wind projects arecommon. For example Totempower provides micro-wind technologies for residen-tial and community use (http://www.totempower.com, Accessed 4th Nov 2014).Rankin Inle, Hudson Bay: (http://www.aadnc-aandc.gc.ca/eng/1100100034302/1100100034418#chp12, Accessed 4th of Oct 2014) is a community energy projectwith 50 Kw micro-wind turbine. mCredit from commercial banks or homemortgage [64] can be used.

Fig. 7. Summary of socio-technical configuration in solar thermal collectors. nGetSolar Lousiana is an example of the commercial vendors providing solar thermalcollector leasing (Source: http://www.getsolarlouisiana.com, Accessed on Sept 30,2013.). oConceptual model of utility driven solar thermal deployment model hasbeen presented by Pöyry Consulting Oy. (Source: http://www.tem.fi/files/37133/TEMrap_28_2013_05072013.pdf, Accessed on Sept 30, 2013). Similarly a fee-for-service conceptual model for third party providers is present in Vitae Civilisinstitution’s report from Brazil. (Source: http://www.green-markets.org/Downloads/SWH_FFS_Brazil.pdf, Accessed Sept 30, 2013.). Etelä Savon Energia in Finlandprovides fee-for-service concept for its’s customers that are outside of districtheating zone (source: http://www.ese.fi/fi/lampo/muut-lamporatkaisut/, AccessedNov 26. 2014.). pThe systems provided for example by SIG Energy Management.(Source: http://www.sigenergy.co.uk/, Accessed on Sept 30. 2013.). qSolar districtheating is emerging topic in European Union. Most of the deployments rely on largescale solar thermal unit. For medium-scale net metering solar heat has been used inSweden, Allbohus Fastighets AB. (Source: http://solarthermalworld.org/content/sweden-growing-number-feed-contracts-district-heating-providers, Accessed Nov 5,2014) and in Finland in so called House A (Source: http://www.jyvaskylanenergia.fi/asuntomessut/alykkaat-energiaratkaisut, Accessed Nov 13, 2014). Conceptualmodel of district heating connected solar thermal collectors have been presentedby Pöyry Consulting Oy in Finland. (Source: http://www.tem.fi/files/37133/TEMrap_28_2013_05072013.pdf, Accessed on Sept 30, 2013). rConceptual model of serviceconcept (without 3rd party ownership) for solar thermal has been proposed by PöyryConsulting Oy. (Source: http://www.tem.fi/files/37133/TEMrap_28_2013_05072013.pdf, Accessed on Sept 30, 2013).

J.K. Juntunen, S. Hyysalo / Renewable and Sustainable Energy Reviews 49 (2015) 857–870 865

difficult. In all likelihood, community-driven micro-generation ofelectricity in hydro, solar PV, and micro-wind is also oftenconnected to the national grid, but nowhere in the reviewedliterature is this explicitly documented.

In all of the heat systems, national networking has been cut offbecause of heat losses that would occur through distribution.Third party ownership models exist for solar thermal deploy-ments, but as yet, only solar thermal has had modest trials withregard to leasing.

Heat pump, wood and pellets biomass feature a similar relativelack of development in their possible socio-technical configurations.Company-driven models, including fee-for-service and ESCO servicefor ground source heat pumps have been trialed. For biomass basedproduction community energy models, are also in place, but fee-for-service has been in modest wider use.

Finally, we have analyzed Waste to Energy (WTE) for micro-generation use. Managing solid waste is a big challenge both indeveloping and developed countries. WTE technologies can reduceboth use of virgin raw materials and carbon emissions. WTE hasbeen widely deployed in large and medium scale plants [88].However, WTE based on small-scale units is less used as thesmaller-scale facilities are less efficient than the larger-scalesystems. WTE based on small-scale technologies are particularlyfeasible for communities in rural or semi-urban areas or regionalcentres. In less densely populated areas the volume of waste,transportation costs or public disapproval may rule out large-scalesolutions [32]. Small-scale thermal energy production has beentraditionally based on combustion concept, which has been almostabandoned, because of its problems: very low energy efficiencyand high dust and polluting emissions [34]. Currently small-scaleunits have been piloted and used for special purposes in commu-nity level providing waste treatment in developing countries forrefugee camps, rural villages, and institutions like hospitals utiliz-ing for example crop residues in farming [91] or hospital waste[92]. The smallest units of WTE technology can be found deployedin the developing countries. These units are used at homes toprovide heat for space heating and cooking.

In our analysis, technologies have been analyzed separately.However, in real life setting many technologies are used in hybridsetups as combination of technologies, which reduces problemsassociated with intermittence, randomness, and uncertainty ofrenewable energy sources. In their current deployments, hybridi-zation has not forced different micro-generation technologies totake similar non-technical positions. This type of isomorphism ofsocio-technical configurations could come about with the matura-tion of the micro-generation business field.

4. Missing socio-technical configurations

Viable business and deployment models on energy generationare often applied (copied) to new areas, environments andtechnologies. This development has been visible among micro-generation technologies. At the same time, there are variouslimitations and barriers that hinder proliferation of certain models,at least “as is” to certain other micro-generation technologies.Based on our review, however, we can recognize several missingsocio-technical configurations, which may open doors for alter-native new business models with micro-generation, despite thelimitations. These issues are discussed in the following.

4.1. Technological limitations

Operation and maintenance needs vary significantly betweentechnologies, and in general heat production requires morefrequent operation than electricity production. Service based

Fig. 8. Summary of socio-technical configuration in heat pump technologies andbiomass. sMicro ESCO concept piloted is piloted by Enespa in Finland. (Source:http://mechanisms.energychange.info/sites/default/files/projectstories/micro-escos_cb-project-story.pdf, Accessed Nov 5, 2014). tEtelä Savon Energia, muncipalityowned utility, in Finland offers ground-source-heat-pump fee-for-service forhouseholds. (Source: http://www.ese.fi/fi/lampo/muut-lamporatkaisut/, AccessedNov 26. 2014.) uGround source heat pumps have been used in community energyproject in Vaasa, Finland. Similar concept can be scaled to micro-generation size.(Source: http://www.varmex-energieffektivisering.se/wp-content/uploads/2011/11/Projektbeskrivning-Geoenergy-Research-Project.pdf, Accessed Nov 5, 2014).vESCO model in wood energy has been used in Finland [60] .wPublic–privatepartnerships are offering small-scale wood pellets systems that have been installedto schools and day-care centres in Finland [12] table, Commercial vendors available.(Source: Energ-Group http://www.energ-group.com/, Accessed on Sept 30, 2013).An example of systems and service provider is HWEnergy in UK (Source: http://www.hwenergy.co.uk/heat-supply-and-ESCO.asp, Accessed Nov 5, 2014). x[60].

Fig. 9. Summary of socio-technical configuration in waste to energy biomass.ySmall-scale gasifiers can be used to recover energy from waste in smallercommunities [87]. Smallest basic incinerators are so called mobile incirenatorsthat can handle between 5 to 120 t of solid waste per day (Source: http://www.sswm.info/content/incineration-small-scale, Accessed Nov 20, 2014). These unitsare used for community purposes, farms, mines, construction sites, hospitals etc.[88]. zBiogas from animal, agricultural, and domestic wastes can be used in biogasplants at homes and are suitable for providing gas and heat for cooking three mealsa day for an average sized family [10]. Domestic-size waste based plants have beenstudied for example in Kenya [89], Rwanda [66] and Cambodia [90].

J.K. Juntunen, S. Hyysalo / Renewable and Sustainable Energy Reviews 49 (2015) 857–870866

business models have gained popularity with technologies thatrequire infrequent operation. Solar PV provides the richest set ofconfigurations and includes several third party, community andend-user driven models. The technology requires relatively littlemaintenance after installation, but in some extreme conditions anactive user can influence output. In cold climate during the winter,the removal of snow from panels becomes important. Similarly,high soiling rate can be an issue is dusty dry areas. In service-based models with technologies requiring frequent operationrequirements, operation maintenance challenges can be addressedby shared responsibilities where incentives for energy users arecreated.

Micro-generation typically provides a competitive energy pricein comparison with external energy sources, i.e. market price.When a (residential) energy user receives locally produced energy(at discount rate), the user also benefits from the high output level.A local ownership option, cash and credit, gives full authority tothe user to control the production unit and full reward tomaximize the production of the unit. Strengers [93] proposesenabling co-management relationships with consumers for peakelectricity demand. Similarly co-management can be expanded toproduction equipment in order to enable the mutual benefits thatmaximize local energy production. However, co-managementapplicability is highly dependent on general skills and knowledgeof the population to operate domestic technologies, which may beinsufficient for example in bottom of the pyramid (BOP) markets.

4.2. Service-based models and limited market demand

Although micro-wind and micro-hydropower can be seen asself-sustaining technologies, they have not attracted third partybusiness models. Khennas and Barnet [94] who researched hydro-power deployment in developing countries explained this as amarket size issue. A third party model is not used because theextent of project developers is largely a function of whether thereis sufficient work for them; i.e. are there sufficient number of newmicro-hydro constructions taking place each year. Natural condi-tions, such as unharnessed rivers, define where it can be deployedat all. In the case of micro-wind and solar thermal, an under-developed market and limited current market size can limitviability of the business, whereas the solar PV market has grownlarge enough to provide companies with economies of scale inoperation and possibility to create profitable business around thethird party ownership model. It should be noted that especially inthe case of a solar thermal collector, a market lease could be anapplicable model if the gained heat production vs. cost of equip-ment ratio is sufficiently high. Because subvention mechanismshave been generally directed towards electricity production, solarPV has been the starting point and entry technology to provideservice-based models such as lease and fee-for-service. In thecountries without government subvention, these models arepractically nonexistent as yet. Nonetheless, service-based modelsof solar thermal collectors appears to be a missing configurationwhich is hard to rationally account for. The concepts of the modelcan be dated back to 2006 [95] and some commercial deploymentshave been planned but commercial providers are still very rare.Similarly, a missing configuration without clear explanation, apartperhaps from a poor fit with extant business models, is thatutilities do not appear to provide fee-for-service solar PV.

Energy Service Company (ESCO) models have been applied tosome heat generating technologies, but the operations are oftendifficult to apply successfully on a small-scale [60]. For heatpumps, micro-ESCO models have been tested but commercialsuccess has been limited to date. However, for biomass systems,third party ownership is an established model and service provi-ders can be found, for example, in the UK.

4.3. Opportunities with community energy

Community energy as a concept consists of a diverse set ofactivities and includes more than energy production [96].Community-energy initiatives can improve energy systems viarenewable energy; energy efficiency, and behavior change [97]. Inthis paper our interest in community activities is solely on energyproduction from renewable sources, and we grouped under com-munity energy initiatives those that have community ownershipand production benefitting multiple households. Micro-generationrefers to small-scale energy technologies and often communityenergy production exceeds the micro-generation scale.

When energy output from micro-generation is distributed tomultiple households, the technical capabilities of distributionbecome essential. In electricity distribution micro-grids can beused, but in heat distribution heat losses can be significant therebycreating limitations9 in community production. Solar thermalcollectors and biomass, are used in community-scale deployments.The visions for using the district heating network for transmittingsolar heat imply models of distributed privately owned collectorsand third party owned distributed solar heat generation. To makethese models viable may require regulatory forced unbundling ofheat production and distribution ownership in a company level ina similar manner that has been done in electricity generation anddistribution earlier.

To date community-scale experiments with ground source heatpumps have remained mostly trials, and present a missing con-figuration. Shared collector fields, potentially heated with solarcollectors in the summer, as well as trials with seabed heat fordistrict wide heat pump installations, point to the technical formsthis can take [28]. Similarly, multiple heat pump combinations inshopping malls provide excellent examples for how the technol-ogy could be managed at a community-scale. In terms of businessmodels, only cash/credit has been available to date, but due totheir easy maintenance and the capacity of being monitoredremotely, other business models could suit community groundsource heat as well.

Finally, we may note that sources to date have not addressedcommunity energy possibilities from the point of view of separatingownership, operations and maintenance, and networking, with distantproximity and close proximity combinations (distant proximity net-working being ruled out due to technical limitations, naturally). Anexample would be third party lease of biomass generation equipmentto a community, which could mitigate the third party barriers inoperation and maintenance of e.g. pellet systems.

5. Policy implications of missing configurations

Analysis of missing configurations revealed three key limitingfactors: technological limitations, limited market demand, and chal-lenges in distribution in the community energy context. Innovationand energy policy mechanisms can used to facilitate all these items.

The cost efficiency of energy technologies is highly dependenton the cost involved during the operation phase. New innovationsespecially addressing the issues of the maintenance and operationof equipment could open new service models for micro-generationtechnologies that have not attracted service business models sofar. We suggest that local innovation trials may [97,98] supportmanufacturers efforts to find new solutions to drive heat basedmicro-generation technologies, in particular, towards a more self-sustaining or remotely controlled operation.

9 Centralized community production unit feeds heat to households insurrounding area.

J.K. Juntunen, S. Hyysalo / Renewable and Sustainable Energy Reviews 49 (2015) 857–870 867

A diverse socio-technical configuration choice set also includesservice-based models. Fee-for-service or leasing can boost marketdevelopment in multiple ways, as has been evident with solar PV.They remove the need for upfront capital investments from con-sumers, and thus have the potential to increase the popularity ofsmall-scale renewable technology in general. In addition, servicecompanies can gain economies of scale in sourcing of equipment,installation and operation, and maintenance. Moreover, end of life-cycle and recycling services can be organized in a professionalmanner. Service-based models can address component quality con-cerns, because this model allows companies to purchase equipmentin volume and use low-cost finance to spread customer costs overthe lifetime of the equipment. It also appears to promote innovation,as in the case of solar utility companies, which can have enoughresources for R&D investments and are large enough to use negotiat-ing power with suppliers [99]. Especially in the developing countriesthird party ownership and credit models are having special impor-tance to increase affordability among the poorer segments of themarket, where lack of capital and loan guarantees are an issue. Inthese markets leasing and fee for services are particularly important[9,54,55]. Household’s knowledge and capability for taking care ofoperation and maintenance of micro-generation technology mightbecome an issue, which support idea of service-based models. In fact,in the countries where adult illiteracy rate is high the lack of skilledand motivated local human resources to build, operate and managemay represents a major barrier even for the corporate driven models[100].

In the early market phase where the limiting market size doesnot attract sufficient commercial vendors, subvention is an impor-tant driver to support market takeoff. Especially FIT tariffs have beenused widely to support electricity generation from solar. FIT for heatproduction, such as solar thermal collectors, is less used with a fewexceptions (e.g. Spain). Also in developing countries main renewablefocus has been in solar PV deployments. Our review echoes earlierresearch by Karezeki [6] and calls for expanding policy supporthorizons for various renewable technological options. Efficientmicro-generation technologies for the use of biomass, for examplecrop residues, would, ensure that scarce biomass resources areeffectively utilised. In addition to eco-efficiency increases moreadvanced micro-generation would alleviate the negative impactsthat burning biomass can affect on women and children’s health.Increased productivity level in basic energy generation could alsoimprove women’s participation possibilities in different economicactivities other than household work. Furthermore, in regardsenergy policy and supporting mechanisms of renewable micro-generation, attention in developing countries should be paid notonly to solar PV but also to solar thermal, windpumps, micro-hydropower. We emphasize the importance within technology andinnovation policy, both in developing and advanced industrialcountries, to drive development towards carbon emissions reductionand remain technology agnostic so as to allow winning innovationsto come about on multiple fronts.

Finally, let us address financing issues that can support theproliferation of micro-generation technologies. Cash, credit, or com-munity ownership options give high autonomy and control toproduction for individual users or groups. These options are applic-able especially among wealthier segments in the developing coun-tries and developed countries. For financial institutions there is spaceto develop new financing instruments (credit schemes) in order toremove the upfront payment10. There are also possibilities to developother types of mechanisms as an example of Francisco DeVries, alsoknown as Property assessed clean energy (PACE), from California

shows. In this Sustainable Energy Financing District, the municipalitytakes part in financing by issuing bonds whose proceeds couldfinance the upfront costs of photovoltaic systems. The participatinghomeowners could use the money they save on their utility bills topay a tax assessment, thereby achieving payback. Unlike in third-party financing, the ownership of the energy production unit restswith the building owner under this model [52,101]. In CaliforniaPACE model has been expanded from initial solar PV technology tocover also HVAC systems, and energy efficiency renovations such asmore efficient windows11. In principle the same model can beutilized for all renewable micro-generation technologies.

6. Conclusions

There is a range of options to deploy micro-generation. In thisstudy we developed the socio-technical framework for renewablemicro-generation and used it to make visible the currently existingand missing configurations in small-scale decentralized energyproduction. Micro-generation takes three main ownership models;consumer (household), community, and company ownership. Weshowed how the versatility of socio-technical configurations withinthese ownership models has, to date, varied significantly betweentechnologies. Some configurations appear to be impossible due tophysical limitations, such as distribution limitations in heat produc-tion because of heat losses, but most configurations are a result of acombination of social, technological and economical factors.

Earlier literature has recognized the impact of various factors onhow socio-technical configurations emerge and diffuse in thelocal marketplace. Within the micro-generation sector, the choicebetween alternatives is a reflection of consumer involvement in theacquisition process, and that variation or a combination of thesemodels is possible [36]. In addition, both politico-institutional andsocio-institutional forces have an impact on the choice between thesemodels as explanations of the variation in level of the activity andbusiness model choice between countries, ventures, and technologies[61]. Our contribution is to extend this thinking and show thatdifferences in technological characteristics, which have a directimpact on operation and management needs, play a key role insocio-technical configurations and enable or hinder proliferation ofcompany-driven models and servicetization of micro-generation. Wesuggest that particular attention should be paid to innovations thatimprove reliability, increase maintenance-free operation times andprovide remote monitoring and maintenance. This applies to heatproducing technologies in particular. Alternative possibilities mightalso emerge from improved ease of use (usability) and the organiza-tion of the operation and maintenance at the site of use or atcommunity level so that operations and maintenance could be leftto consumers whilst the ownership and distribution of heat mightreside with a third party operator. We can also recognize technolo-gies, such as solar thermal collectors, that could well meet operationalrequirements of service-based models, but which have not yetattracted business interest. At the policy level, there is space todevelop new mechanisms for small-scale heat production in mannersimilar to that which has been used to support the scale up ofelectricity micro-generation in manymarkets. In developing countriesspecial focus should be put on expanding energy policy measuresfrom solar PV to other renewable micro-generation technologies.

The present study concentrates on current ways of organizingaround micro-generation technologies. Its temporal context is con-fined to the operation of micro-generation when a certain organiza-tional set up around a technology has been already established. Our

10 Financial institutions may not consider micro-generation products to bevalid for collateral security, which increases interest rate in the credit pricing.

11 Movers in the Spread of California’s PACE programs (Source: Cleantechnica,https://cleantechnica.com/2014/11/26/movers-in-the-spread-of-californias-pace-programs/, accessed 27 Nov. 2014).

J.K. Juntunen, S. Hyysalo / Renewable and Sustainable Energy Reviews 49 (2015) 857–870868

contribution opens several avenues for further research on socio-technical configurations. It points out that academic research onmicro-generation technologies and related business models requiresfrequent updates to avoid falling behind the rapidly developing field.It also underscores new points of focus such as how installationwork is organized before the socio-technical configuration of energyproduction has taken its organizational form, or how configurationtrajectories have developed over time. There are significant country-specific variations in micro-generation technology diffusion. Forexample, supporting mechanisms play a crucial role in the earlydevelopment of servicetization. In this study FIT and other support-ing mechanism were excluded in order to be able extensively coverselected dimensions. Servicetization may also hinder the develop-ment of local energy autonomy from a user perspective, even if itmay also provide a boost for market development and lead toincreasing popularity, lower prices and reliability of equipment forautonomous consumers in the long run.

Acknowledgements

The researchers have received funding for the present workfrom Fortum Foundation (Grant number: 201200215) and MarcusWallenberg Foundation (Grant: “Climate change and the socialconstruction of a market for new energy solutions in Finland”).

References

[1] Akorede MF, HizamH, Pouresmaeil E. Distributed energy resources and benefitsto the environment. Renewable Sustainable Energy Rev 2010;14:724–34.

[2] Wolsink M. The research agenda on social acceptance of distributed genera-tion in smart grids: renewable as common pool resources. RenewableSustainable Energy Rev 2012;16:822–35. http://dx.doi.org/10.1016/j.rser.2011.09.006.

[3] Allen SR, Hammond GP, McManus MC. Prospects for and barriers to domesticmicro-generation: a United Kingdom perspective. Appl Energy 2008;85:528–44.

[4] Watson J, Sauter R, Bahaj B, James P, Myers L, Wing R. Domestic micro-generation: economic, regulatory and policy issues for the UK. Energy Policy2008;36:3095–106. http://dx.doi.org/10.1016/j.enpol.2008.04.028.

[5] Thiam DR. An energy pricing scheme for the diffusion of decentralizedrenewable technology investment in developing countries. Energy Policy2011;39:4284–97. http://dx.doi.org/10.1016/j.enpol.2011.04.046.

[6] Karekezi S, Kithyoma W. Renewable energy strategies for Rural Africa: is a PV-led renewable energy strategy the right approach for providing modern energyto the Rural Poor of Sub-Saharan Africa? Energy Policy 2002;30:1071–86.

[7] Chakrabarti S, Chakrabarti S. Rural electrification programme with solarenergy in remote region—a case study in an Island. Energy Policy2002;30:33–42.

[8] Urmee T, Harries D, Schlapfer A. Issues related to rural electrification usingrenewable energy in developing countries of Asia and Pacific. RenewableEnergy 2009;34:354–7. http://dx.doi.org/10.1016/j.renene.2008.05.004.

[9] Mainali B, Silveira S. Renewable energy markets in rural electrification:country case Nepal. Energy Sustainable Dev 2012;16:168–78. http://dx.doi.org/10.1016/j.esd.2012.03.001.

[10] Sovacool BK. Design principles for renewable energy programs in developingcountries. Energy Environ Sci 2012;5:9157. http://dx.doi.org/10.1039/c2ee22468b.

[11] Walker G, Cass N. Carbon reduction, the public and renewable energy:engaging with socio-technical configurations. Area 2007;39:458–69.

[12] Bijker WE, Pinch TJ, Hughes TP. The social construction of technologicalsystems: new directions in the sociology and history of technology. MIT;1987.

[13] The governance of large technical systems. In: Coutard O, editor. London:Routledge; 1999.

[14] Elzen B, Geels FW, Green K. System innovation and the transition tosustainability: theory, evidence and policy. Cheltenham, UK: Edward Elgar;2004.

[15] Frei CW. What if…? Utility vision 2020 Energy Policy 2008;36:3640–5.[16] Wolfe P. The implications of an increasingly decentralised energy system.

Energy Policy 2008;36:4509–13. http://dx.doi.org/10.1016/j.enpol.2008.09.021.[17] Small F, Frantzis L. The 21st century electric utility: positioning for a low-

carbon future. Boston, MA: Ceres; 2010.[18] Richter M. Business model innovation for sustainable energy: German

utilities and renewabe energy. Luneburg: Centre for Sustainability Manage-ment (CSM) Leuphana Universitat Luneburg; 2011.

[19] Houwing M, Ajah AN, Heijnen PW, Bouwmans I, Herder PM. Uncertainties inthe design and operation of distributed energy resources: the case of micro-

CHP systems. Energy 2008;33:1518–36. http://dx.doi.org/10.1016/j.energy.2008.07.003.

[20] Smith A, Stirling A. The politics of social–ecological resilience and sustain-able socio-technical transitions. Ecol Soc 2010;15:11.

[21] Fleck J. Configurations: crystallizing contingency. Int J Hum Factors Manuf1993;3:15–36. http://dx.doi.org/10.1002/hfm.4530030104.

[22] Hyysalo S. Health technology development and use: from practice-boundimagination to evolving impacts. London: Routledge; 2010.

[23] Frantzis L, Graham S, Katofsky R, Sawyer H. Photovoltaic business models.Colorado: National Renewable Energy Laboratory Golden, CO; 2008.

[24] Nimmons J, Taylor M. Utility solar business models: emerging utilitystrategies & innovation. Solar Electric Power Association (SEPA) Publication;2008.

[25] Duncan R. Renewable energy and the utility—the next 20 years. RenewableEnergy World 2010.

[26] Richter M. Utilities’ business models for renewable energy: a review.Renewable Sustainable Energy Rev 2012;16:2483–93. http://dx.doi.org/10.1016/j.rser.2012.01.072.

[27] Schoettl J-M, Lehmann-Ortega L. Photovoltaic business models: threat oropportunity for utilities? In: Wüstenhagen R, Wuebker R, editors. Handbookof research on energy entrepreneurship. Cheltenham, UK: Edward Elgar;2011. p. 145–71.

[28] Walker G, Cass N. Public roles and socio-technical configurations: diversityin renewable energy deployment in the UK and Its Implications. In: Devine-Wright P, editor. Renewable energy and the public from NIMBY to participa-tion. London: Earthscan; 2010. p. 43–56.

[29] Dudhani S, Sinha AK, Inamdar SS. Assessment of small hydropower potentialusing remote sensing data for sustainable development in India. EnergyPolicy 2006;34:3195–205. http://dx.doi.org/10.1016/j.enpol.2005.06.011.

[30] Kosa P, Kulworawanichpong T, Srivoramas R, Chinkulkijniwat A, HorpibulsukS, Teaumroong N. The potential micro-hydropower projects in NakhonRatchasima province, Thailand. Renewable Energy 2011;36:1133–7. http://dx.doi.org/10.1016/j.renene.2010.09.006.

[31] Thornton A, Monroy CR. Distributed power generation in the United States.Renewable Sustainable Energy Rev 2011;15:4809–17.

[32] IEA.. Review of small scale waste conversion systems. International EnergyAgency; 2004.

[33] Biffa Waste Services. Future perfect—an analysis of Britain’s waste produc-tion and disposal account, with implications for industry and governmentfor the next twenty years. Bucks, UK; 2002.

[34] Iakovou E, Vlachos D, Toka A. A methodological framework for integratingwaste biomass into a portfolio of thermal energy production systems. In:Karagiannidis A, editor. Waste to energy: opportunities and challenges fordeveloping and transition economies, London. London: Springer; 2012.p. 59–82.

[35] Peterson D, Haase S. Market assessment of biomass gasification andcombustion technology for small-and medium-scale applications. Colorado:National Renewable Energy Laboratory Golden, Colorado; 2009.

[36] Sauter R. Socio-technical implications of domestic microgeneration technol-ogies in the UK electricity system. Int J Environ Technol Manage2008;9:204–19.

[37] Bracken LJ, Bulkeley HA, Maynard CM. Micro-hydro power in the UK: the roleof communities in an emerging energy resource. Energy Policy2014;68:92–101. http://dx.doi.org/10.1016/j.enpol.2013.12.046.

[38] Sauter R, Watson J. Strategies for the deployment of micro-generation:implications for social acceptance. Energy Policy 2007;35:2770–9. http://dx.doi.org/10.1016/j.enpol.2006.12.006.

[39] Rae C, Bradley F. Energy autonomy in sustainable communities—a review ofkey issues. Renewable Sustainable Energy Rev 2012;16:6497–506. http://dx.doi.org/10.1016/j.rser.2012.08.002.

[40] Christensen CM, Rosenbloom RS. Explaining the attacker’s advantage:technological paradigms, organizational dynamics, and the value network.Research Policy 1995;24:233–57.

[41] Poyry Management Consulting Oy. Aurinkolammon liiketoimintamahdolli-suudet kaukolammon yhteydessa Suomessa; 2013.

[42] Juntunen JK. Domestication pathways of small-scale renewable energytechnologies. Sustainability 2013 ForthcomingScience, Practice, and Policy2013 Forthcoming.

[43] Sovacool BK. Expanding renewable energy access with pro-poor publicprivate partnerships in the developing world. Energy Strategy Rev2013;1:181–92. http://dx.doi.org/10.1016/j.esr.2012.11.003.

[44] Walker G. What are the barriers and incentives for community-ownedmeans of energy production and use? Energy Policy 2008;36:4401–5.

[45] Diaz-Rainey I, Tzavara D. Financing the decarbonized energy system throughgreen electricity tariffs: a diffusion model of an induced consumer environ-mental market. Technol Forecasting Soc Change 2012;79:1693–704. http://dx.doi.org/10.1016/j.techfore.2012.05.012.

[46] Ross SJ, McHenry MP, Whale J. The impact of state feed-in tariffs and federaltradable quota support policies on grid-connected small wind turbineinstalled capacity in Australia. Renewable Energy 2012;46:141–7. http://dx.doi.org/10.1016/j.renene.2012.03.019.

[47] Boon FP, Dieperink C. Local civil society based renewable energy organisa-tions in the Netherlands: exploring the factors that stimulate their emer-gence and development. Energy Policy 2014;69:297–307. http://dx.doi.org/10.1016/j.enpol.2014.01.046.

J.K. Juntunen, S. Hyysalo / Renewable and Sustainable Energy Reviews 49 (2015) 857–870 869

[48] Derrick A. Financing mechanisms for renewable energy. Renewable Energy1998;15:211–4.

[49] Dornan M. Solar-based rural electrification policy design: the renewableenergy service company (RESCO) model in Fiji. Renewable Energy2011;36:797–803. http://dx.doi.org/10.1016/j.renene.2010.07.015.

[50] Drury E, Miller M, Macal CM, Graziano DJ, Heimiller D, Ozik J, et al. Thetransformation of southern California’s residential photovoltaics marketthrough third-party ownership. Energy Policy 2012;42:681–90. http://dx.doi.org/10.1016/j.enpol.2011.12.047.

[51] Friebe CA, von Flotow P, Täube FA. Exploring the link between products andservices in low-income markets—evidence from solar home systems. EnergyPolicy 2013;52:760–9. http://dx.doi.org/10.1016/j.enpol.2012.10.038.

[52] Hess DJ. Industrial fields and countervailing power: the transformation ofdistributed solar energy in the United States. Global Environ Change2013;23:847–55. http://dx.doi.org/10.1016/j.gloenvcha.2013.01.002.

[53] JCCM Huijben, GPJ. Verbong. Breakthrough without Subsidies? PV businessmodel experiments in The Netherlands Energy Policy 2013;56:362–70. http://dx.doi.org/10.1016/j.enpol.2012.12.073.

[54] Lemaire X. Fee-for-service companies for rural electrification with photo-voltaic systems: the case of Zambia. Energy Sustainable Dev 2009;13:18–23.http://dx.doi.org/10.1016/j.esd.2009.01.001.

[55] Lemaire X. Off-grid electrification with solar home systems: the experienceof a fee-for-service concession in South Africa. Energy Sustainable Dev2011;15:277–83. http://dx.doi.org/10.1016/j.esd.2011.07.005.

[56] Liu X, O’Rear EG, Tyner WE, Pekny JF. Purchasing vs. leasing: a benefit-costanalysis of residential solar PV panel use in California. Renewable Energy2014;66:770–4. http://dx.doi.org/10.1016/j.renene.2014.01.026.

[57] Mainali B, Silveira S. Financing off-grid rural electrification: country case Nepal.Energy 2011;36:2194–201. http://dx.doi.org/10.1016/j.energy.2010.07.004.

[58] Nieuwenhout FDJ, Van Dijk A, Lasschuit PE, Van Roekel G, Van Dijk VAP,Hirsch D, et al. Experience with solar home systems in developing countries:a review. Prog Photovoltaics: Res Appl 2001;9:455–74.

[59] Obeng GY, Evers H-D. Impacts of public solar PV electrification on rural micro-enterprises: the case of Ghana. Energy Sustainable Dev 2010;14:223–31. http://dx.doi.org/10.1016/j.esd.2010.07.005.

[60] Okkonen L, Suhonen N. Business models of heat entrepreneurship in Finland.Energy Policy 2010;38:3443–52.

[61] Provance M, Donnelly RG, Carayannis EG. Institutional influences on businessmodel choice by new ventures in the microgenerated energy industry.Energy Policy 2011;39:5630–7. http://dx.doi.org/10.1016/j.enpol.2011.04.031.

[62] Rai V, Sigrin B. Diffusion of environmentally-friendly energy technologies:buy versus lease differences in residential PV markets. Environ Res Lett2013;8:014022. http://dx.doi.org/10.1088/1748-9326/8/1/014022.

[63] Richter M. German utilities and distributed PV: how to overcome barriers tobusiness model innovation. Renewable Energy 2013;55:456–66. http://dx.doi.org/10.1016/j.renene.2012.12.052.

[64] Walker A. Financing distributed generation. Energy Eng 2002;99:21–47.[65] Watson J. Co-provision in sustainable energy systems: the case of micro-

generation. Energy Policy 2004;32:1981–90.[66] Landi M, Sovacool BK, Eidsness J. Cooking with gas: policy lessons from

Rwanda’s national domestic biogas program (NDBP). Energy Sustainable Dev2013;17:347–56. http://dx.doi.org/10.1016/j.esd.2013.03.007.

[67] Smith A, Kern F, Raven R, Verhees B. Spaces for Sustainable Innovation: SolarPhotovoltaic Electricity in the UK. Technological Forecasting and Social Change2014;81:115–30. http://dx.doi.org/10.1016/j.techfore.2013.02.001.

[68] Pollitt M. Does electricity (and Heat) network regulation have anything tolearn from fixed line telecoms regulation? Energy Policy 2010;38:1360–71.http://dx.doi.org/10.1016/j.enpol.2009.10.070.

[69] Buchan, D. The Energiewende-Germany’s Gamble; 2012.[70] Foxon T, Gross R, Chase A, Howes J, Arnall A, Anderson D. UK innovation

systems for new and renewable energy technologies: drivers, barriers andsystems failures. Energy Policy 2005;33:2123–37.

[71] Adebayo E, Sovacool BK, Imperiale S. It’s about dam time: improvingmicrohydro electrification in Tanzania. Energy Sustainable Dev2013;17:378–85. http://dx.doi.org/10.1016/j.esd.2013.03.003.

[72] Jiayi H, Chuanwen J, Rong X. A review on distributed energy resources andMicroGrid. Renewable Sustainable Energy Rev 2008;12:2472–83. http://dx.doi.org/10.1016/j.rser.2007.06.004.

[73] Asmus P, Lauderbaugh A, Lawrence M. Forecasts for commercial/industrial,community/utility, campus/institutional, military, and remote microgrids:2013–2020. Boulder, CO: Navigant Research; 2013.

[74] Hong GW, Abe N. Sustainability assessment of renewable energy projects foroff-grid rural electrification: the Pangan-an Island Case in the Philippines.Renewable Sustainable Energy Rev 2012;16:54–64. http://dx.doi.org/10.1016/j.rser.2011.07.136.

[75] Oliver M, Jackson T. The market for solar photovoltaics. Energy Policy1999;27:371–85.

[76] Verbong GPJ, Beemsterboer S, Sengers F. Smart grids or smart users?Involving users in developing a low carbon electricity economy EnergyPolicy 2012.

[77] Steinheimer M., Trick U., Ruhrig P. Energy communities in smart markets foroptimisation of peer-to-peer interconnected smart homes. In: 2012 Eighthinternational symposium on communication systems, networks & digitalsignal processing (CSNDSP), Poznan University of Technology, Poznan,Poland; 2012, 1–6.

[78] Zahedi A. Maximizing solar PV energy penetration using energy storagetechnology. Renewable Sustainable Energy Rev 2011;15:866–70. http://dx.doi.org/10.1016/j.rser.2010.09.011.

[79] Chen H, Cong TN, Yang W, Tan C, Li Y, Ding Y. Progress in electrical energystorage system: a critical review. Prog Nat Sci 2009;19:291–312. http://dx.doi.org/10.1016/j.pnsc.2008.07.014.

[80] Díaz-González F, Sumper A, Gomis-Bellmunt O, Villafáfila-Robles R. A reviewof energy storage technologies for wind power applications. RenewableSustainable Energy Rev 2012;16:2154–71. http://dx.doi.org/10.1016/j.rser.2012.01.029.

[81] Evans A, Strezov V, Evans TJ. Assessment of utility energy storage options forincreased renewable energy penetration. Renewable Sustainable Energy Rev2012;16:4141–7. http://dx.doi.org/10.1016/j.rser.2012.03.048.

[82] Fernandes D, Pitié F, Cáceres G, Baeyens J. Thermal energy storage: how previousfindings determine current research priorities. Energy 2012;39:246–57. http://dx.doi.org/10.1016/j.energy.2012.01.024.

[83] Hadjipaschalis I, Poullikkas A, Efthimiou V. Overview of current and futureenergy storage technologies for electric power applications. RenewableSustainable Energy Rev 2009;13:1513–22. http://dx.doi.org/10.1016/j.rser.2008.09.028.

[84] Taylor, P.G., Bolton, R., Stone, D., Upham, P. Developing pathways for energystorage in the UK using a coevolutionary framework. Energy Policy 2013.doi:10.1016/j.enpol.2013.08.070.

[85] Hall PJ. Energy storage: the route to liberation from the fossil fuel economy?Energy Policy 2008;36:4363–7. http://dx.doi.org/10.1016/j.enpol.2008.09.041.

[86] Nfah EM, Ngundam JM. Identification of stakeholders for sustainable renew-able energy applications in Cameroon. Renewable Sustainable Energy Rev2012;16:4661–6. http://dx.doi.org/10.1016/j.rser.2012.05.019.

[87] Waste to energy conversion technology. In: Klinghoffer NB, Castaldi MJ,editors. Philadelphia, PA: Woodhead Pub; 2013.

[88] Waste to energy: opportunities and challenges for developing and transitioneconomies. In: Karagiannidis A, editor. London: Springer London; 2012.

[89] Bazilian M, Nussbaumer P, Eibs-Singer C, Brew-Hammond A, Modi V,Sovacool B, et al. Improving access to modern energy services: insightsfrom case studies. Electr J 2012;25:93–114. http://dx.doi.org/10.1016/j.tej.2012.01.007.

[90] Buysman E, Mol APJ Market-based. Biogas sector development in leastdeveloped countries—the Case of Cambodia. Energy Policy 2013;63:44–51.http://dx.doi.org/10.1016/j.enpol.2013.05.071.

[91] Vera D, Jurado F, Margaritis NK, Grammelis P. Experimental and economicstudy of a gasification plant fuelled with olive industry wastes. EnergySustainable Dev 2014;23:247–57. http://dx.doi.org/10.1016/j.esd.2014.09.011.

[92] Ellyin C. Small-scale waste-to-energy technologies. Columbia University;2012 master’s thesis.

[93] Strengers Y. Peak electricity demand and social practice theories: reframing therole of change agents in the energy sector. Energy Policy 2012;44:226–34.

[94] Khennas S, Barnett A Final synthesis report prepared for department forinternational development. UK and World Bank, Contract R7215; 2000.

[95] Rodrigues D., Kaufman S. Business prospects for solar water heating fee-for-service operations in Brazil; 2006.

[96] Walker G, Devine-Wright P. Community renewable energy: what should itmean? Energy Policy 2008;36:497–500.

[97] Hielscher S, Seyfang G, Smith A. Grassroots innovations for sustainableenergy: exploring niche-development processes among community-energyinitiatives. In: Cohen MJ, Vergragt PP, Szenjwald Brown H, editors. Innova-tions in sustainable consumption: new economics, socio-technical transi-tions and social practices. Cheltenham: Elgar; 2013. p. 133–58.

[98] Hyysalo S, Juntunen JK, Freeman S. User innovation in sustainable homeenergy technologies. Energy Policy 2013;55:490–500.

[99] Duke RD, Jacobson A, Kammen DM. Photovoltaic module quality in theKenyan solar home systems market. Energy Policy 2002;30:477–99.

[100] Schmidt TS, Blum NU, Sryantoro Wakeling R. Attracting private investmentsinto rural electrification—a case study on renewable energy based villagegrids in Indonesia. Energy Sustainable Dev 2013;17:581–95. http://dx.doi.org/10.1016/j.esd.2013.10.001.

[101] Jenkins M. Miller-McCune: Francisco DeVries Invents a Financing Mechanismthat Makes Rooftop Solar Affordable in Berkeley and Other Cities . ⟨https://renewfund.com/news/miller_mccune_francisco_devries_invents-2448⟩;2009.

J.K. Juntunen, S. Hyysalo / Renewable and Sustainable Energy Reviews 49 (2015) 857–870870