5.6 off main-grid systems for access to electricity

Off-main-grid systems for access to electricity

Eng. Stefano Mandelli [email protected]. Lorenzo Mattarolo [email protected]

UNESCO Chair in Energy for Sustainable DevelopmentDepartment of Energy

Outline

1. Technologies and appropriateness2. Centralized Vs off-main-grid electrification3. Introduction to off-main-grid systems generation

technologies

Technologies and Appropriateness

NEW APPROACHImportance of local resources and local human capitalSupported by Schumacher – “Small is Beautiful, Economics as if People Mattered” (1973)Identification of technologies 1. small-scale

2. labour-intensive3. energy efficient4. environmental friendly5. locally controlled

STARTING POINT - THE CONTEXTOver reliance on colonial administrationTop-down approach to economic developmentLow technological capacity development

TOP DOWN

BOTTOM UP

NEW CONCEPT OF DEVELOPMENTTechnology that fits in the country's infrastructure, affordable,easy to properly maintain, not destructive to the environment.(Kaplan, 1994)

SUSTAINABILITY

Importance of boundary conditions• flexibility to adapt to local conditions• not related to a defined technology mix• scaled to the context• tailored to the needed services• accounting the local culture

Appropriate technologies

Economic feasibility• business model enhancing sustainability• counting the coverage and cost

The ‘space pen’ example!

Ownership/commitment• involvement of final users• end-users requirements• installation, management and maintenance• enhancing job creation• strengthening of research institutions to support

local production

Replicability• Increase access to new technologies of scale • Innovative models to scale up technologies• Preserving the environment

Functionality• availability of local materials• impact on human capacity• final user ownership

Appropriate technologies

Impact• Access to modern energy services and electricity necessarily need to be linked to

other social or economic strategy.• The implementation of energy programmes have to be measured over socio-

economic indicators such as: quality of life, education, health, information, agriculture, transport, promotion of small enterprises.

(Asociación Argentina de Energía Eólica )

Centralised generation

Large power plants in central locationHuge transmission and distribution gridsLarge number of consumers

Graphic representation of centralized electrical system

Paradigm of centralised electrical systems

Centralized Vs Off-main-grid electrification

At the beginning of the electrification era• System were decentralized

End of the first era of electrification• System moved to centralised electrical system

Developed versus Developing countries• In Developed Countries area has been electrified by the ‘70.• In Developing countries the issue has not be solved yet (2013)

Little or no autonomy of monopoly enterprises vs governmentWeak financial capacityAid (if any) is used for maintenance rather then capital investment Huge transmission and distribution gridsThe focus is more on urban then rural area (Low interest for utilities)

Liberalised Marked and Competition• Around the ‘80s two mains drivers started the end of the centralised era

• Increase efficiency• Attract private capitals (to reduce public burden)

Centralised generation


Five dimensions are promoting the spreading of decentralised and distributed generation based on Renewable energies1. Technological improvement (technical dimensions)

• increased performance of the small power technologies• development of electronic metering and control equipment• increased consumer demands for highly reliable power supply

2. Environmental concerns (environmental dimension)• growing concern as for the greenhouse gases emissions• public awareness of the impacts of the electric industry• opposition to building new transmission lines

3. Economic opportunities (economic dimensions)• to avoid transmission and distribution related costs• To tackle the current risky nature of large scale plant investments• to reduce power plants costs with combined heat and power generation• to better exploit profit margins within the competitive market

Beyond Centralised generation


Five dimensions are promoting the spreading of decentralised and distributed generation based on Renewable energies4. Political asset (political dimensions)

• to decrease dependence from fossil fuels• to increase primary source diversification (energy mix)• to reduce vulnerability of the supply chain in centralized systems

5. Social issues (social dimension)• increasing public desire to promote “green technologies”• growing interest towards energy autonomy communities and

sustainabilityTwo other issues essential for Developing Countries• Accessibility (socio-economic and technical dimension)• Poverty reduction (socio economic and political dimension)

Beyond Centralised generation


Classification of electrification systems

•Large power plants in central location

•Huge transmission and distribution grids

•Size effect •Large

number of consumers

Centralised systems

Off Main Grid Systems


• DECENTRALISED SYSTEMS• Built by autonomous units (one single source)

• Locally based and Need oriented• Restricted number of consumers

• DISTRIBUTED SYSTEMS• Based on a number of decentralised systems

• Interacting trough a transmission distribution grid• Virtual power plant

Off Main Grid Systems


Decentralised and Distributed generation• Decentralised (single unit single source) can be:

• Consumer/need oriented • Home based system => for household• Community based systems => for community needs• MSEs or SMEs based systems => for micro/small/medium enterprises

• Multipurpose• Micro Grid

• Distributed can be:• Hybrid system (renewable + diesel)• Size is limited < 5 MWel• No connection to the main grid (“off-main-grid” microgrid)

bottom up & top down approach can be mixedA network of smart minigrid that can be connected….

1 source, 1 component, 1 customer

1 source, multi component, multi customer

multi source, multi component, multi customer

Electrification via “off-main-grid systems”

Off-main-grid Systems for rural areas

Off-main-grid systems


Off-main-grid Systems for rural areasGeneration technologies can be identified as follows

Off-main-grid systems generation technologies

Off-main-grid Systems: conventionalConventional systems are mainly diesel-powered generators (gen-sets). Widely used to improve the access to electricity and for emergency.

Advantages- dispatchable on demand- simple technology- require reduced civil work and time for installation- meet low rural power demand- have a low capital cost per kW

Disadvantages- high maintenance and fuel costs (including transportation), - high noise generation, - low efficiency when operating far from nominal conditions (they operates at 20-30%

of the nominal conditions - environmental implications


Off-main-grid Systems: non-conventionalNon-conventional energy systems are Renewable Energy Technologies (RETs) : photovoltaic (PV), wind, pico and micro-hydro (PH, MH) systems. These technologies are selected based on existing practices, policies, and technological maturityAdvantages- Energy security - lower energy prices in the long term:

- efficiency are increasing prices are decreasing- flexibility and modularity, - low maintenance, and reduced environmental impact Disadvantages - aleatory nature of the sources, especially solar and wind, - storage is a mandatory component

- increasing cost, complexity and maintenance)- high dependence on weather conditions (solar, wind), seasonal (hydro, wind

technologies) and daily cycles (solar)

Þ attention to the peak load demand and to the temporal load distribution is required


Off-main-grid Systems: non-conventionalNon-conventional energy systemsbiomass-based technologies are not included even if biomass is considered one of the most important renewable sources in the near future.Two are the reasons:- the minimum plant size for electricity production

- The minimum scale for electricity production from biomass is estimated to be 10-100 kW, fitting the Microgrid scale but not the home-based and community-based typical scale

- The steam cycle technology is available for loads higher than 5 MW, suitable for grid-connected generation plants

- the complexity of the supply chain. - Biomass is largely used on small-scale energy systems for thermal applications, while for

power generation a large-scale combustion/gasification plant is necessary - The extremely complex and multidisciplinary biomass supply chain requires specific deep

analyses that are not tackled in this chapter. - Good management of the whole supply chain is required


Off-main-grid Systems: hybridHybrid systems are often built up with diesel generator technology coupled with RET-based system.

Advantages • high reliability and continuity of supply• reduction of the storage system size• batteries lifetime and operation costs benefit

Disadvantages • higher investment and maintenance costs than pure RET use. • hybrid solution increases the complexity of the system • the management and maintenance of different technologies is required
