Chair of Energy Economics, Prof. Dr. Möst

Prof. Dr. Dominik Möst, Berlin, October 2014

www.ee2.biz

Economics of Energy StorageThe Role of Storage in

Energy System Flexibility

TU Dresden, Chair of Energy Economics, Prof. Dr. Möst 3

Storage applications –its the competition what matters …

• Energy arbitrage

• Ancillary services

• Avoidance of renewable curtailment

• Generation, transmission & distribution grid deferral

• End user application

• Managing energy costs and RE-feed-in (also P2H)

• Emergency application

• Electric Mobility

TU Dresden, Chair of Energy Economics, Prof. Dr. Möst 4

Agenda for today …

How to determine the economic need of

additional storage power plants?

1. From a system perspective

• Which technologies are required in the future?

(also depends on the assumptions made)

• What need for energy storages, especially electricity storage exists?

Use of energy system models or bottom-up electricity market model!

2. From a market based view

• Is the power plant economic at todays market prices?

• What is my expectation about future market prices?

• How will the market look like and where are which incentives?

Expectation about price developments and use a model optimizing the

plant dispach at exogenous prices!

TU Dresden, Chair of Energy Economics, Prof. Dr. Möst 5

Simple peak load model

Technology 1

(Peaker) Technology 2Technology 3

(Base-load)

Time [h]

Costs

[€/MW]

P inst, 3

P inst 2

Load duration curve

[MW]

Time [h]

P inst, 1

t1 t2 t3

Cvar1*t1

Cvar2*t2

Cvar3*t3

Cfix1

Cfix2

Cfix3

But where can a storage plant

be sorted in?

• Is a storage plant investment

cheaper than a gas turbine?

No!

• Is a storage plant operation

cheaper than a gas turbine?

Yes!

• Storage power plant makes

arbitrage between low base-

load and high peak load prices

• What will change in the future?

8760 h

Storage plant ?

CST

TU Dresden, Chair of Energy Economics, Prof. Dr. Möst 6

What is the residual load curve and how do renewable sources affect

the residual load curve?

Residual load = Demand – Renewable feed-in

… has to be satisfied by flexible (in general conventional capacities)

How will residual load changein 2020 / 2030 due to RES-E?

• Peak: nearly no change

• Off-peak: increasing amount ofhours with surplus energy

Load duration curve[MW]

Time [h]

TU Dresden, Chair of Energy Economics, Prof. Dr. Möst 7

System perspective

Adaptation of „optimal“ capacity?

Technology 1

Technology 2Technology 3

Time [h]

Costs

[€/MW]

P inst, 3

P inst 2

Load duration curve

[MW]

Time [h]

P inst, 1

t1 t2 t3

Cvar1*t1

Cvar2*t2

Cvar3*t3

Cfix1

Cfix2

Cfix3

Necessary generation portfolio –

what will change?

• Reduction of base-load and

mid-load

• Increase of peak-load

• Increase of storage power

plants

What to do with the surplus?

• Store

Decreases variable production

costs (as surplus will probably

be „cheap“)

• Export

• Demand Side Management (Smart Market)

• Curtail surplus8760 h

Storage plant ?

CST

TU Dresden, Chair of Energy Economics, Prof. Dr. Möst 8

The integration of renewable energy sources (RES) significantly influences the

residual load:

Number of hours with negative residual load rises

Surplus of RES feed-in increase

Level of maximal negative residual load grows

What to do with the surplus?

• Store, export or curtail?

„Real“ data for Germany:

Hours with surplus renewable feed-in will increase

-70

-50

-30

-10

10

30

50

70

90

GW

w/o RES feed-in with RES feed-in

-70

-50

-30

-10

10

30

50

70

90

GW

w/o RES feed-in with RES feed-in

German load duration curve in 2010 German load duration curve in 2030

TU Dresden, Chair of Energy Economics, Prof. Dr. Möst 9

Electricity system model ELTRAMOD to analyse the interdependence

between storage need, grid extension and renewable curtailment

Model purpose

• Fundamental system analysis

• Integration of renewable energy sources (RES)

in the European electricity market

• Flow calculation based on Net Transfer Capacity (NTC)

• Trade-off between grid and storage extensions

• Optimal dispatch of power plant capacity

Main characteristics

• Bottom-up electricity market model

• Temporal resolution of 8760 hours

• Calculation of the cost-minimal generation dispatch and investments in additional

transmission lines and storage facilities

• Country specific times series of wind and PV feed- in

TU Dresden, Chair of Energy Economics, Prof. Dr. Möst 11

Removing the feed-in obligation and its impact on grid and storage

extension

Also for keeping up obligation feed-in a RES surplus supply will occur

The shifting to curtailment schemes has got a low impact no integrated RES generation

=> However: significant difference for grid and storage extensions settings

Central statement:

From the economic point of view it is not optimal to integrate every available unit of RES.

RES should be demanded for system stability and further market integration.

=> Mid term perspective: grid extension and stronger market integration, then storage…

feed-in obligation curtailment

Non integrated RES surplus supply withoutgrid and storage extensions

10.2% 11.9%

Non integrated RES surplus supply with gridand storage extensions

0.9% 3.7%

Additional transmission capacities up to 2050 (NTC)

252.2 GW 143 GW

Additional storage capacities up to 2050 35.7 GW 7.9 GW

TU Dresden, Chair of Energy Economics, Prof. Dr. Möst 12

Impact of RES-E share and CO2-prices

Share of RES-E generation

• Mid-term (< 40%): Nearly no change in storage demand

• Long-term (>60%):

Increase of storage demand, but still moderate

• Long-long-term (>85-90%)

Significant increase of storage demand!

Cost of CO2

• Low CO2-price (<15 €/t): Good for storage power plant (cheap base-load)

• High CO2-prices (>40 €/t): Amount of storage at 50% RES-E at about

todays storage level

=> Storage need is quite sensitive to RES-E share and CO2 costs, but

unfortunately in a cotradicting way!

TU Dresden, Chair of Energy Economics, Prof. Dr. Möst 13

How to determine the economic need of

additional storage power plants?

1. From a system perspective

• Which technologies are required in the future?

(also depends on the assumptions made)

• What need for energy storages, especially electricity storage exists?

Use of energy system models or bottom-up electricity market model!

2. From a market based view

• Is the power plant economic at todays market prices?

• What is my expectation about future market prices?

• How will the market look like and where are which incentives?

Expectation about price developments?

TU Dresden, Chair of Energy Economics, Prof. Dr. Möst 14

Decentral storage options /

End user applications

• Manage energy costs

(= arbitrage)

• In Germany:

Arbitrage possible between approx.

200 €/MWh and 300 €/MWh

Use for own consumption

and save 30 Cent/kWh vs.

feed-in (10 Cent/kWh) => 200 €/MWh

or even loose it => 300 €/MWh

Possibilities to commercialize storage capacities

Central electricity storage options

• Arbitrage

Decreasing price differences

(< 60 €/MWh)

• Ancillary services

Offer capacity

Decentral storage options have about 5 times higher incentives

• but strongly dependend on regulation (grid fees, feed-in tarif, market rules, …)

• Decentral option: strong drivers will lead to market uptake …

• Central option: how will energy prices differences develop?

TU Dresden, Chair of Energy Economics, Prof. Dr. Möst 15

-20

0

20

40

60

80

100

120

140

160

180

200

1 1001 2001 3001 4001 5001 6001 7001 8001

Stro

mp

reis

e [

€/M

Wh

]

2002

2003

2004

2005

2006

2007

2008

2009

Development of electricity prices and price gap

between peak and off-peak prices

2002

2003

2004

2005 2006

2007

2008

2009

Price duration curve 2002-2009

Zeit [h]

0

20

40

60

80

100

120

140

2002 2003 2004 2005 2006 2007 2008 2009[E

uro

/MW

h]

Durchschnittspreis1000-teuersten h

Durchschnittspreis1300-günstigsten h

Standard-abweichung

TU Dresden, Chair of Energy Economics, Prof. Dr. Möst 16

System perspective

Adaptation of „optimal“ capacity?

Technology 1

Technology 2Technology 3

Time [h]

Costs

[€/MW]

P inst, 3

P inst 2

Load duration curve

[MW]

Time [h]

P inst, 1

t1 t2 t3

Cvar1*t1

Cvar2*t2

Cvar3*t3

Cfix1

Cfix2

Cfix3

Extension of renewables

• merit-order effect of renewables

• Pressure on prices, but

„correct“ price signal

• market not in equilibrium

state and overcapacities

are not earning sufficient

money

phase-out of base and mid load

Policy interventions and

introduction of

capacity markets?

8760 h

Capacity phase-out

Surplus

for free?

Higher amount of peaker,

but up to now no price signal

(=overcapacities)

TU Dresden, Chair of Energy Economics, Prof. Dr. Möst 17

Base load units (lignite, coal)

Transition to renewables:

The merit-order effect of renewables (long-term effect)

(without introduction of capacity markets)

Euro

/MW

h

hIn a long-term view, the merit order effect of RES will change the price

duration curve and with it the generation portfolio.

=> Base-peak-spread will increase in the mid to long-term

Peak load units (gas, oil)

Peak price will increase

Base load under pressure(up to you have to pay for

“waste disposal”)

Current prices (under pressure)• RES-E extension underestimated

• Demand overestimated

Past (2006 – 2010)

Today (2011-2020)

Future (2025+)

TU Dresden, Chair of Energy Economics, Prof. Dr. Möst 18

Conclusion

Storage demand is in the short-/mid-term (often) overestimated, while effort

for necessary grid extension is underestimated

Storage demand depends on RES-E share, but also on other developments,

such as CO2-price (unfortunately in contradiction)

In the long-term: storage demand will increase,

especially with RES-E shares > 60%

From load orientation towards RES-E orientation:

market prices under pressure (and this will be the case in the next years)

Role of Europe vs. national strategies?

Fakultät für Wirtschaftswissenschaften, Lehrstuhl für Energiewirtschaft, Prof. Dr. Möst