International Colloquium “Renewable Energy Sources: Environmental and Social Issues”

STUDY COMMITTEE C3, System Environmental Performance

International Colloquium

“Renewable Energy Sources:

Environmental and Social Issues”

Oporto (Portugal), 23rd September 2009

The results of the work of CIGRÉ WG C3.05 “Environmental impact of Dispersed Generation (DG)”

Dr. Thomas Smolka, Convener of WG C3.05


1000

Total energy

consumption, EJElectric energyconsumption TWh

500

1998 2000 2010

30,000

20,000

10,000Forecast by IEA

Electric energy

Total energy

Year

Expected energy consumption growth (2000-2020):- total energy: + 2.5 %/a- electric energy: + 3,5 %/a

Adaption of installed power generation and transmission resp. distribution capacity required

Emission and greenhouse-gas reduction in future Energy systems

Limitation of the political-economical dependency on energy imports

Increasing prices of fossil fuels caused by resource limitations and cost-intensive exploration

Ensuring access to cheap and high quality use-energy

Integration of dispersed generation (mainly renewables) in future power grids

Motivation – global trends and prerequisites


Change in Power Generation in each Country Example: Energy Generation Mix Scenarios for Germany in 2030

• Increasing renewable power

• Gas (incl. Biogas) is the dominating energy source

• High increase of Renewables in the system0,00

10,00

20,00

30,00

40,00

50,00

60,00

70,00

80,00

90,00

100,00

Basis Efficiency Nuclear Renewable

Po

wer

Gen

erat

ion

Pro

po

rtio

n [

%]

Black Coal Black Coal CHP Brown Coal Brown Coal CHP

Nuclear Fuel Oil Gas Gas CHP

Hydro Power Wind Power PV Geothermal Energy

others (Biomass, waste)


Climate Change Effects in different Scenarios

• General trend of reduced emissions in all scenarios

0

100

200

300

400

500

600

2010 2020 2030

GW

P in

g C

O2-

eq./k

Wh

Basis

Efficiency

Nuclear

Renewable


Aim of the Working GroupMission

The aim of the working group is to define procedures and methods to evaluate the environmental impact of Dispersed Generation (DG).

The WG shall proceed by developing the steps that follow:

• Collection and analysis of practical experience (from technical literatures and/or “case studies”) about assessments of the environmental impacts of DG and of legislation and technical standards in various countries.

• Synthesis and benchmarking of methods and experiences-> Identification of critical issues.

• Definition of criteria and proposal of a standardized methodology.

• Illustration of methodology in a case study

• Dissemination of conclusions (Target Groups: National and Local Authorities and Agencies, Regulators, Manufacturers, Electric Utilities)


Difficulties in the Definitionof Dispersed Generation

How should DG be defined?


Definition of Dispersed Generation

WG C3.05 defines Dispersed Generation (slightly modified to to CIGRE SC C6, WG 37-23 definition from 1999):

• today not centrally despatched• today not centrally planned• connected to the distribution network (MV, LV)• smaller than 50 MW• based on co-generation units (heat and electricity), renewable energies or

other conventional sources• Examples for DG are micro turbines, internal combustion engines, wind

energy and photovoltaic converters, mini hydropower systems, biomass and waste material power systems fuel cells, etc..


LCA Methodology by ISO 14042ff

RAW MATERIALEXTRACTION

DISPOSAL

PRODUCTION

UTILIZATION

Life cycleof a

product or system

Life-Cycle Assessment approach is a proven methodology for environmental impact assessment of any product or technical system

Work flow

1. Definition of a methodology/model for assessing the environmental impacts of DG

2. Explanation of the procedure by case studies


Impact categories and areas of protection

Resources

HumanHealth

NaturalEnvironment

Climate change

Resource depletion

Land use

Water use

Human toxic effects

Ozone depletion

Photochemical ozone creation

Ecotoxic effects

Eutrophication

Acidification

Areas of protection


Different Approaches for Environmental Impact Evaluation of DG

Component Level• Environmental Impacts of different

technologies (over whole lifecycle)e.g. WEC approx. 20-30 g CO2/kWh

• Results available by LCA studies for all DG technologies

System Level• Operation of DG with other DG units in

distribution networks influenced by centralized power plants

• System aspects on component level view not included e.g.

– Impacts by Cogenerated heat – Impacts by reduced/increased power

losses– Which scenario of DG in power grids

leads to minimized emissons?• Results NOT available or known over the

whole lifetime of DG in operation in a distribution network

New Analysis on System Level

necessary

Operation of DG in Distribution Networks


Energy - Flows in Distribution Networks

Energy Supply of a Distribution Network (MV/LV)

Thermal and Electrical Energy Demand

of End-Consumer

Dispersed Generation Units

<50MW

Large Power Plant

(Thermal, Nuclear, Hydro,

Solar, Wave Power Plant

etc.)>50MW

Output of the System: Thermal Energy Electrical Energy

Primary Energy Carrier (e.g. Coal, Gas, Biomass, Wind, Sun)

Thermal EnergyHeat Supply System

(Heat Network)

Power Supply System(Power Grid)

High Voltage Network (HV/EV)

Elec. + therm.

StorageElec.

Storage

Elec. Storage



DG Unit<50MW

g CO2/kWhel

g SO2/kWhth

t CO2/a....


Scenario Analysis as Tool in Case Study Analysis

AnalyzingActual Situation

2010

2020

2030

PositiveDesperate Scenario

NegativeDesperate Scenario

Trend Scenario

A

A1

Failure Decision Point / Correction

Scenario Developement of ScenarioChange of Developement

Pathby Failure


Future Topics in Distribution Networks

Assessment of dispersed electric vehicles in distribution networks

• Can electric vehicles offer new ancillary services for the power grid?• How should the vehicles be integrated to ensure a sustainable mobility and higher energy efficiency in future smart grids?


Thank you very much for your attention!

Questions?


Backup


LCA of a Distribution Network with DG

Technical analysis

Software based LCAAsset management & Disposal

Operation

Power Generation, Energy Demand, Transmission losses, SF6 losses, etc.

Service and maintenance

Basic conditions

Installation & Manufacturing

Materials, energy consumption

External conditions

Political demands, generation-mix out of HV

Environmental impacts

Global Warming Potential, Acidification Potential, Eutrophication Potential, etc.


Key questions for a global procedure

How can environmental impacts of dispersed generation in distribution grids be measured (methodology -> Life-Cycle Assessment, Eco-Efficiency)?

How to deal with technical impacts on the system e.g. reduced power losses, cogenerated heat?

Under which conditions has distributed generation (DG) advantages to today‘s power plants (ecological and economical) ?

Does a wide decentralisation lead to less emissions in distribution networks or should the central power generation structure be maintained?


Critical Issues by influencing parameters integrated in the balance object

• DG Technology– Efficiency of current und future DG technologies might be considered due to

long operation times of DG in distribution networks-> time dependence of evaluation -> importance for power grid planning

– Operating modes of DG (heat, power or net optimized operation)– Lifetime of components– Generation costs and CO2 trading

• Impacts on the system level– Power and Heat Reduction out of the overlaying system– Reduced power losses -> reduced emissions?– Efficiency of current und future of large power plant technologies– Allocation

• Consumer Side’s Influence– Uncertainties in heat and power demand of consumers (time dependent)– Influence on energy efficiency programs on consumer behavior


Technical Model of Electrical Energy Supply

Electrical Demand of the End Customer in the Model System

DG based on Renewables

Environmental Impacts of End-Consumers Electricity Demand

Gas Distr.System

DG based on fossil Energy

Carriers

Local Electrical Energy Mix

Balance Object Electrical Energy

Supply of a Distribution Network (MV/LV)

Global Electrical Energy Mix from Large Power Plants of HV power Grid

Primary Energy Carrier (Coal, Natural Gas, Oil etc.)


Renewables (Wind, Sun, Water,

Biomass etc.)


Technical Model of Thermal Energy Supply

Thermal Demand of the End Customer

Heat Mix

Environmental Impacts of End-Consumers Heat Demand

Secondary Energy from Power Plant Fleet

Electr. Power Grid

DistrictHeating System

Heat Pumps/ Direct Electr. Heating

Balance Object Electrical Energy Supply of a Distribution Network (MV/LV)

DG based on Renewables

Gas Distr.System

DG based on fossil Energy

Carriers

Primary Energy Carrier (Coal, Natural Gas, Oil etc.)

Renewables (Sun,

Biomass etc.)

Gas Distr.System

Renewables (Wind, Biomass, Geothermal Sun, Water, Air etc.)

Primary Energy Carrier (Natural Gas)

Documents

International Colloquium “Renewable Energy Sources: Environmental and Social Issues”