How to fill the gap?

Wir schaffen Wissen – heute für morgen

Paul Scherrer Institut, Laboratory for Energy Systems Analysis Christian Bauer, P. Eckle, K. Volkart, W. Schenler

Reducing the carbon footprint of the Swiss power sector:

How to fill the gap?

Reference scenario:

CO ₂ reduction in the Swiss power sector

To be replaced by alternatives with lower GHG

emissions

El ec tric ity gene ration [PJ ]

Research question to be answered

Given (a) certain preference profile(s):

Which will be the preferred options for CO ₂ reduction in the Swiss power sector in the future?

Reference year 2035

Comparing different alternatives according to multiple criteria

Method

Multi-Criteria Decision Analysis (MCDA)

• Comparing various electricity generation technologies

• Taking into account environmental, economic & social evaluation criteria

• Allowing stakeholder interaction by considering individual weighting of criteria/indicators

• using the weighted sum approach

MCDA: How does it work?

Selection of technology options (alternatives) Selection of criteria & indicators

Quantification of indicators for each alternative Normalisation of indicators

Weighting of indicators

Aggregation: Combination of indicator values & weighting factors

→ Ranking of alternatives

Goal: CO ₂ reduction in the power sector

Alternatives for CO ₂ reduction in the Swiss power sector

• Hydro: reservoir & run-of river

• Photovoltaic: mc- & a-Si, roof-top

• Wind: onshore & offshore (import)

• Geothermal: Enhanced geothermal system

• Wood: with & w/o CCS (sustainable forestry)

• Biogas: from organic waste

• Nuclear: EPR

• Natural Gas CC: with CCS

• Hard coal & lignite: with CCS (import)

• Solar thermal (import)

Differing generation potentials need to be considered in conclusions!

online MCDA tool

http://www.mightymcda.net

Selection of indicators

Four main categories:

• Environment

• Economy

• Society

• Security of supply

Selection of indicators

Environment – based on LCIA

• fossil energy demand (CED) [MJ/t CO ₂ avd.]

• nuclear energy demand (CED) [MJ/t CO ₂ avd.]

• metal depletion (ReCiPe) [kg Fe-eq/t CO ₂ avd.]

• ecosystem quality (ReCiPe) [species*a/t CO ₂ avd.]

• GHG emissions (IPCC 2007 + biog. CO ₂ ) [kg CO ₂ -eq/t CO ₂ avd.]

Economy

• CO ₂ avoidance costs [CHF/t CO ₂ avd.]

• capital costs (investments) [CHF NPV]

• fuel sensitivity [share of fuel costs]

• marginal avoidance costs [marginal CHF/t CO ₂ avd.]

Selection of indicators

Society

• conflict potential [ordinal scale]

• direct employment [person*a/t CO ₂ avd.]

• impacts on human health (ReCiPe) [DALY/t CO ₂ avd.]

• expected fatalities (severe accidents) [fatalities/t CO ₂ avd.]

• max. number of fatalities (severe accidents) [max. fatalities/accident]

• waste: chemical & radioactive (LCI results) [m ³ /t CO ₂ avd.]

Security of supply

• share of domestic supply [ordinal scale]

• diversity of resources [ordinal scale]

• reliability [ordinal scale]

GHG emissions from electricity generation (preliminary)

-8.0E-01 -6.0E-01 -4.0E-01 -2.0E-01 0.0E+00 2.0E-01 4.0E-01 6.0E-01 8.0E-01 1.0E+00

Rese rvo ir Run

-o f-ri ve r E P R

NGCC NGCC

-p ost A TR H

2CC

A TR H 2CC

-pre NG CHP

W oo d co m b.

W oo d co m b. -p ost

S NGCC S NGCC

-po st

B iog as CHP P V m ulticr

ist. S i r oo f

P V a m orph

ou s S i r oo f W in d o

nsh ore Ge oth erm

al

W in d o ffsh ore

Con ce ntr.

S olar- th er m . Hard

co al PC Hard

co al PC-po st

Hard

co al PC-oxy Hard

co al IG C C

Hard co al IG

C C- pre Lig nite

P C

Lig nite P C- po st Lig nite

P C- oxy Lig nite

IGCC

Lig nite IGCC

-p re

k g CO 2 eq/k W h

NGCC emission level

Example: impacts on human health (ReCiPe H) (preliminary)

0.0E+00 2.0E-07 4.0E-07 6.0E-07 8.0E-07 1.0E-06

R es erv oir R un-of

-riv

er EPR N GC

C -p os t AT R H 2C C -pre

W ood com

b.

W ood com

b. -pos t SN

GC C

SN GC

C -pos t

Biogas CHP m ult ic ris t. Si roof

orphous Si roof W in d ons hore Geothermal

W in d of fs hore ent

r. Solar-t herm

.

ard coal

PC -pos

t

H ard coal

PC -ox

y

coal IGC

C -pre Lignit

e PC -pos

t

Lignit e PC

-ox y

Lignit e IGC

C -pre

ReCi Pe H [DA LY/k W h]

Example: impacts on human health (ReCiPe H) (preliminary)

best

worst

no rma liz ed DAL Y pe r t CO 2 avoi de d

Weighting of indicators

Stakeholder profiles (exemplary)

1. focus on health & environment 2. focus on economy

3. focus on autonomous electricity supply & social factors

Weighting of indicators: 3 profiles

MCDA results (preliminary): profile health & environment

best

worst

MCDA results (preliminary): profile economy

best

worst

MCDA results (preliminary): profile social & autonomous supply

best

worst

Summary & Conclusions

• MCDA tool allows a transparent & interactive evaluation of technology options

• Considering stakeholder preference profiles & a comprehensive set of evaluation criteria/indicators

• Showing pros & cons of each alternative

• Preliminary MCDA results for CO ₂ reduction in the Swiss power sector

• Hydro shows in general a good performance (BUT: very limited potential)

• Decentralized renewables tend to perform better than fossil power with CCS

• Biomass combustion with CCS turns out to be a good option

• Limited potentials of renewables to be considered → NGCC with CCS

Outlook

• Generation of final indicator results

• Extension to further economic sectors with high potential for CO ₂ reduction: residential, industry, mobility

• Consideration of efficiency measures

• Implementation of stakeholder interaction:

→integration of real preference profiles

Thanks for your attention!

More information:

christian.bauer@psi.ch; kathrin.volkart@psi.ch http://gabe.web.psi.ch/

Research carried out within the project „CARMA“:

http://www.carma.ethz.ch/