Flexibility options in the electricity system

Dr. G. Papaefthymiou, K. Grave 22/05/2014

Can we achieve 100% renewables? Flexibility options in the electricity system Webinar Leonardo Energy

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Overview

1. Definition of power system flexibility

2. Need for Flexibility

3. Overview of Flexibility Options

4. Mapping of Flexibility Options

5. Conclusions and recommendations

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Overview







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The key physical components of flexibility:

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Demand

Supply

Network

System

System

Demand: partly controllable

Network: ability for spatial matching

System: operational rules

Supply: controllable or intermittent (RES)

Dr. G. Papaefthymiou

> Power systems are designed to ensure a spatial and temporal balancing of generation and consumption at all times.


Definition of Power System Flexibility

> Power system flexibility represents the extent to which a power system can adapt electricity generation and consumption as needed to maintain system stability in a cost-effective manner.

> Flexibility is the ability of a power system to maintain continuous service in the face of rapid and large swings in supply or demand.

> Measures of flexibility: – Ramp rates, minimum up/down times, and start-up/shut-down

times are commonly used indicators of flexibility, measured as MW available for ramping up and down over time

> Role of power networks:

– Key enablers of flexibility, since they define the spatial dimension of balancing and thus to which extent flexibility resources can be shared between adjacent areas.

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Overview








Daily patterns of net electricity demand for different VRES penetration levels

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-20

0

20

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Syst

em N

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eman

d (G

W)

No RES

Hours




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Hourly ramping range of net electricity demand for different VRES penetration levels

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urly

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Hours

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-40

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Spot

pric

e [€

/MW

h]

Gen

erat

ion

/ De

man

d [G

W]

Kernenergie Braunkohle Kohle Erdgas Öl Andere Pumpspeicher Laufwasser Saisonspeicher Wind Solar Unbekannt

Monday Tuesday Wednesday Thursday Friday Saturday Sunday

Nuclear Lignite Oil

Hydro storage Other

Natural Gas Pump storage

unknown Run of River

Export

Wholesale price

Coal

Demand

Oversupply events already happen

Oversupply event:

High RES

Low Demand

CGs at their limit

Source: EEX, ENTSO-E,

the example shows

German ex-post data

for one week in

February 2011



Dynamic range of net electricity demand for different VRES penetration levels

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-60

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0

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Syst

em N

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eman

d (G

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No RES 20% 40% 60% 80%

Hours

BASELOAD

MIDLOAD

PEAK LOAD



Need for flexibility

> Traditional power systems: Need for flexibility because of demand variations and sudden loss of generation units – variability of demand – uncertainty of supply • Flexibility provided by supply side (power plant fleet)

> Introduction of variable RES: – Increasing the need for flexibility: Increase in variability

and uncertainty in the supply side – Reduction of the flexibility potential: VRES displace part

of the conventional generation capacity (impact on portfolios and operational)

• New flexibility options are needed



Impacts of VRES on the flexibility timeline

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Long term planning flexibility Does my system have sufficient resources to manage operational variability?

Operational planning flexibility: How many flexibility resources should be committed to ensure secure operation?

Operational Flexibility: Which are the most economic resources?


Source: H. Holttinen, A. Tuohy, M. Milligan, E. Lannoye, V. Silva, S. Muller, L. Soder, The flexibility workout: Managing variable resources and assessing the need for power system modification, IEEE Power & Energy Magazine, November/December 2013


Overview








Categorisation of flexibility options

System

Energy Storage

Supply

Net-work

Demand



Overview of flexibility options

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Supply

Demand

Energy Storage

System

Net-work

1. Flex Coal, 2. Gas

3. Oil, 4. Biogas,

5. CHP, 6. Nuclear

7. VRES

8. Pump storage,

9. (AA-)CAES

10. Flywheels

11. Batteries

12 Hydrogen (Power to Gas)

13. Demand Response

- Energy intensive industries

- Services

- Smart applications

14. Electric vehicles

15. Heat pumps

16. Resistance heating

17. Network expansion (Installation of lines)

- Add transmission capacity (HVAC /HVDC)

- Increase meshing, alleviate congestions

18. Power flow control (“smart“ devices)

- Flow control devices PST, FACTS, HVDC

19. Market Rules

20. Market integration:

- Expansion of markets

- Expansion of control zones



Overview








Mapping of flexibility options

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Short term flexibility Long term flexibility

Lower ST/MT flex potential, unit commitment constraints

Mid term flexibility

SUPP

LY

Coal

Lower ST/MT flex potential, unit commitment constraints

Lignite

Lower ST flex potential, unit commitment constraints

CCGT Flex mode can be enhanced

Flexible – high variable costs OCGT

High variable costs, limited local supply Biogas

Stochastic behaviour – Perceptual and political concerns(waste of ´free´ energy) VRES APC

Flexible –high variable costs, emissions ICE

Nuclear

Constrained due to primary operation Large CHP

Constrained due to primary operation Micro CHP

DEM

AND

Industrial DR High potential – flexibility constrained by primary industrial process

Small scale DR High potential – flexibility depends on user behaviour

Electric Vehicles

Heat pumps

Electric heating

STO

RAG

E

Pumped Hydro Low potential for extra expansion

AA-CAES Low efficiency, restricted potential for expansion

Very high investment costs Flywheels

Technology development needed for efficiency improvement Batteries

Low efficiency – option for seasonal storage Power to gas

Constrained by transport sector/primary operation

Constrained by heat sector/primary operation

Constrained by heat sector, low efficiency

Red options are small-scale distributed technologies – communication & control infrasturcture key enabler Bold/Underscore options are mature technologies – maturity of most demand and storage options is low



Market barriers


-20000

0

20000

40000

60000

80000

100000

120000

1 5001

Ohne EE20% EE40% EE

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00000

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00000

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00000

0% 2% 4% 6% 7% 9% 11%

13%

15%

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30%

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34%

35%

37%

39%

41%

43%

45%

47%

48%

50%

52%

54%

56%

58%

60%

61%

63%

65%

67%

69%

71%

73%

74%

76%

78%

80%

82%

84%

86%

87%

89%

91%

93%

95%

97%

99%

Grundlasttechnologie

Mittellasttechnologie

Spitzenlasttechnologie

Cost

s [€/

kWa]

time [h] 8760 0

8760 0

Dem

and

[GW

]

0% VRES 40% VRES

Peak load technology

Middle load technology

Base load technology

20% VRES

Residual load curve shifts because of additional VRES

time [h]

Base load technology

Middle load technology

Peak load technology

0% VRES 20% VRES 40% VRES

> VRES have low marginal costs – Downward pressure to electricity prices, – Reduced full-load hours for conventional units

> Still, conventional peak power plants are needed to meet load in times of low VRES generation.

> How to incentivize flexibility? – Supply options are driven by market prices – Flexibility options are driven by market price

variability (spreads)


Overview








The Flexibility Gap


Low High

Existing Supply Flex New Supply Flex

Flex

ibili

ty

VRES

Flex

ibili

tyG

ap

Storage Flex

Demand Flex


Conclusions and recommendations


> A flexibility gap is created by the shift towards high-VRES systems

> New flexibility options in demand and storage require control and communication infrastructure

> VRES control is unavoidable for higher RES shares

> Changing the market is needed for reducing the flexibility gap

> Incentives and systems for demand management are needed

> Extending the market size is a no regret solution

© ECOFYS | | 22/05/2014 27

Questions?

> Dr. Georgios Papaefthymiou Ecofys Germany GmbH Am Karlsbad 11 10785 Berlin Germany E: [email protected] I: www.ecofys.com
