nuclear power and renewables in low-carbon electricity systems

Nuclear Power and Renewables in Low-Carbon Electricity Systems:

System Effects and System Costs- A case study

A. Voß R. Barth H. Brand J. Apfelbeck

Institute of Energy Economics and the Rationale Use of Energy (IER),University of Stuttgart

8th Meeting of the Working Party on Nuclear Energy Economics15th - 16th May 2012 in Paris

15th May 2012Nuclear Power and Renewables in Low-Carbon Electricity Systems: System Effects and System Costs 2

Issues addressed● What are the total costs of different electricity systems that are

characterized by different shares of renewables as well as of nuclear energy?

● What are the effects of nuclear and renewable power generation on CO2-emissions and wholesale electricity prices?

● What is the interaction of renewables and nuclear energy?


Approach● Case study of an electricity system using the framework context of Germany

as an example

● Analysis of total electricity system costs due to required electricity generation, storage as well as transmission and distribution including:i. Balancing and provision of adequate back-up capacities

ii. Grid connection, extension and reinforcement

iii. Environmental externalities: Climate-change externalities taken into account by a price for the usage of CO2 allowances

● Comparison of scenarios with equal electricity demand and reliability of supply but with differenti. shares of partially fluctuating electricity generation based on renewable energies

ii. installed capacities of nuclear power plants

● Quantitative analyses based on fundamental electricity system modelling


Short model descriptionElectricity Market Model E2M2s● European Electricity Market Model,

stochastic version

● Optimization of investments in power plants based on fossil fuels (and storages)

● In this application given exogenously: Renewable power generation and capacities of nuclear power plants

● Possibility to treat wind supply with stochastic programming

● Provision of power reserve, intertemporal unit commitment

Unit Commitment Model JMM● Joint Market Model

● Optimization of unit commitment and provision of power reserve in hourly time resolution for one year

● Time sequence of wholesale markets (day-ahead, intra-day)

● Possibility to consider short term forecasts of wind generation and electricity demand by means of rolling planning and stochastic programming


12 scenarios considered● Combination of different shares of renewable electricity generation in

the annual electricity demand with different installed capacities of nuclear power plants

Installed capacities of nuclear power plants

0 GW 20.7 GW 41.4 GW

Share of renewable energies

15 % RES-15%_NUCL-0 RES-15%_NUCL-21 RES-15%_NUCL-41





Assumptions for all scenarios● Annual electricity demand (including grid losses, excluding pumping

energy): 550 TWh

● Fuel prices of coal and gas corresponding to projections of World Energy Outlook 2010 “New policies scenario” for the year 2030, CO2-allowance prices: 50 €/t CO2

● No export or import possibilities to neighbouring electricity systems

● Original state of present transmission and distribution grid of the exemplary electricity system sufficient to accommodate conventional and nuclear electricity generation

● Battery storages of electric vehicles available to the electricity system: 48 GW installed power and 48 GWh storage capacity


Installed capacities and electricity generation based on renewable energies

non‐controllable and fluctuating:

Wind offshore

Wind onshore

Photovoltaics

controllable / continuous:

Biomass

Hydro

12 %

13 %

10 %

27 %

19 %

16 %

Percentages: share of generation in annual electricity demand

0

50

100

150

200

250

15% 35% 50% 80%

Installed capacity [GW] / [G

Wp]

0

50

100

150

200

250

300

350

400

450

500

15% 35% 50% 80%

Net e

lectricity

gen

eration [TWh]

12 %

13 %

10 %

27 %

19 %

16 %

5%

10 %

7 %


Demand load and residual load - 50 % share of RES

● Excess renewable power up to 27 GW● Renewable surplus production ~ 2 TWh, about 1 % of the electricity

production by wind and photovoltaics● Storage capacity requirement ~ 250 GWh

-80-60-40-20

020406080

100

0 1.000 2.000 3.000 4.000 5.000 6.000 7.000 8.000

Dem

and

and

resi

dual

load

[G

W]

Hour [h]

Demand load Residual load


Demand load and residual load - 80 % share of RES

● Excess renewable power up to 78 GW● Renewable surplus production ~ 43 TWh, about 13 % of the electricity

production by wind and photovoltaics● Storage capacity requirement ~ 6,4 TWh

-80-60-40-20

020406080

100

0 1.000 2.000 3.000 4.000 5.000 6.000 7.000 8.000

Dem

and

and

resi

dual

load

[G

W]

Hour [h]

Demand load Residual load


Storage capacity

0

1000

2000

3000

4000

5000

6000

7000

0 1000 2000 3000 4000 5000 6000 7000 8000

Sto

rage

cap

acity

[GW

h]

Hour [h]

80 % share of renewable energies50 % share of renewable energies

● 50 % share of renewables:i. Present German pump storages, planned new pump storages and purchase rights from

abroad offer sufficient storage capacities● 80 % share of renewables:

i. Cost optimal storage capacity of 4.2 TWh with a loading power of 54.8 GWii. Curtailment of fluctuating electricity generation from wind and PV power plants


Power system portfolio

0

50

100

150

200

250

300

350

400

NUCL‐0

NUCL‐21

NUCL‐41

NUCL‐0

NUCL‐21

NUCL‐41

NUCL‐0

NUCL‐21

NUCL‐41

NUCL‐0

NUCL‐21

NUCL‐41

RES‐15% RES‐35% RES‐50% RES‐80%

Net gen

erating capacity [G

W]

Photovoltaics

Wind offshore

Wind onshore

Pump storage

Biomass

Hydro

Natural gas GT

Natural gas CC

Coal

Nuclear

15th May 2012Nuclear Power and Renewables in Low-Carbon Electricity Systems: System Effects and System Costs

Annual electricity generation

12

0

100

200

300

400

500

600

700NUCL‐0

NUCL‐21

NUCL‐41

NUCL‐0

NUCL‐21

NUCL‐41

NUCL‐0

NUCL‐21

NUCL‐41

NUCL‐0

NUCL‐21

NUCL‐41

RES‐15% RES‐35% RES‐50% RES‐80%

Electricity

gen

eration [TWh]

PhotovoltaicsWindPump storageBattery storage, mobileBiomassHydroNatural gas GTNatural gas CCCoalNuclear


Annual total system costs and CO2-emissionsCO2‐Emissions [Mio. t]:

244 121 268 155 69 204 100 46359

0

10

20

30

40

50

60

70

80

90

100

NUCL‐0 NUCL‐21 NUCL‐41 NUCL‐0 NUCL‐21 NUCL‐41 NUCL‐0 NUCL‐21 NUCL‐41 NUCL‐0 NUCL‐21 NUCL‐41

RES‐15% RES‐35% RES‐50% RES‐80%

System

Costs [B

illion €]

Fuel costs Costs CO2 allowancesOther costs, conventional Conventional, investment costsConventional, fixed operating costs RES, investment costsRES, fixed operating costs Storages, investment costsTransmission grid, investment and fixed operating costs Distribution grid, investment and fixed operating costs

102 51 41


Electricity wholesale prices (marginal generation costs)

0

20

40

60

80

100

120

140

160

180

200

0 1000 2000 3000 4000 5000 6000 7000 8000

Electricity

price [€/M

Wh]

Hour [h]

RES‐15%_NUCL‐0

RES‐15%_NUCL‐21

RES‐15%_NUCL‐41

RES‐35%_NUCL‐0

RES‐35%_NUCL‐21

RES‐35%_NUCL‐41

RES‐50%_NUCL‐0

RES‐50%_NUCL‐21

RES‐50%_NUCL‐41

RES‐80%_NUCL‐0

RES‐80%_NUCL‐21

RES‐80%_NUCL‐41


Conclusions● Large shares of renewables, in particular of fluctuating renewables, considerably

increase the total installed power plant capacities.● No substantial reduction of the required conventional power plant capacities due

to renewables.● With nuclear power in the power system, both total system costs and CO2-

emissions are considerably reduced. Whereas electricity generation based on renewables increases system costs.

● It is more cost efficient to curtail electricity generation from wind and PV power plants in order to avoid costs of large storage capacities.

● Costs for reinforcements of both transmission and distribution grids due to the feed-in of renewables far from load centres and at lower voltage levels constitute a significant part of total electricity system costs.

● In the scenarios described, the effect of increasing nuclear electricity generation on the reduction of wholesale electricity prices (based on marginal generation costs) is larger than of increasing renewables.


Thank you for your attention!

Institute of Energy Economics and the Rational Use of Energy, IERProf. Dr.-Ing. A. Voß – [email protected]

Photo credits:© GDF Suez/Electrabel

nuclear power and renewables in low-carbon electricity systems

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