Energy storage and its role in Germany s Energiewende

Transcription

1 Energy storage and its role in Germany s Energiewende Central results of an actual study (BMWi, FA 43/12) Dipl.-Ing. Andreas Becker Japan, Nov

2 Energie-Forschungszentrum Niedersachsen Energy Research Center of Niedersachsen Our partners: Fields of research: 2

3 Content Introduction / Motivation Key results / Executive summary Detailed presentation of selected technical aspects Fields of application and storage technologies Assignment and evaluation Supporting secure grid operation Detailed presentation of selected economical and legal aspects Costs for operational security in Germany Responsibilities concerning the operation of storage systems 3

4 Operational Security terms and definitions Definition according to entso-e: Operational Security means the Transmission System capability to retain a Normal State or to return to a Normal State as soon and as close as possible, and is characterized by thermal limits, voltage constraints, short-circuit current, frequency limits and stability limits. In practice: No special indicator / index exists describing the actual level of Operational Security. entso-e: european network of transmission system operators for electricity 4

5 TSO s responsibility to ensure system security 13 Abs.1 EnWG: If system security is endangered, TSO s have to deploy necessary remedial actions affecting grid and market operation (including Redispatch and Counter-Trading). 13 Abs.2 EnWG: If system security is still endangered, TSO s have to deploy advanced remedial actions : To force changes in power generation Selective load rejection and changes in cross-border-transits Quantities of measures according to 13 Abs.1 Number of hours Quantities of measures according to 13 Abs.2 Number of hours TSO: Transmission System Operator Source: 50Hertz, Tennet 5

6 Power generation from renewables until 2017: Estimate of usable energy amount from storage utilization GWh/a Theoretical amount of energy Theoretische from renewables EEG-Menge 35 TWh in 2017 can made available by use of storage devices Usable amount of energy Nutzbare EEG-Menge from renewables without storage integration Source: Volkswagen AG 6

7 Short version key results Principally, storage units have the capability to contribute to system reliability even with a high share of fluctuating energy. The need for storage units is dependent on the further development of renewable energy sources and other flexibility options such as the grid expansion. There is no ideal, unique storage technology. Various storage technologies depending on the location and application purpose - such as short and long-term storage - are needed. Numerous suitable storage technologies are still in the development stage (long term research and development). Concerning their timewise availability and costs, no reliable statements can currently be made. 7

8 Classification of relevant storage technologies 8

9 Potential fields of application for storage systems In the future all system services actually provided by conventional power plants have to be supplied by new components. Electrical grid inertia Elimination of rotating masses of generators and turbines Old NPP-generators as rotating masses, phase shifter Voltage control and mains protection Provision of reactive power and short circuit power Added value of storage systems? Potential fields of application Primary-, Secondary- and Tertiary-Control Balancing short-term fluctuations in seconds to hours frequency control, grid stability Seasonal balancing Utilizing potential national energy surpluses Addition / Alternative to cold reserve? Source: EFZN / Becker 9

10 Assignment of storage technologies for possible application areas Active power supply inertia Primary control Secondary Minute reserve Seasonal balancing control Flywheel storage Superconductive magnetic storage Super Caps / double layer capacitor Battery / Redow flow battery Pump storage power plant Compressed air storage (adiabatic) ++ (++) + (-) ++ (+) ++ (+) - (-F) chemical energy carriers F F F F F Electrolysis -- ++F negative CR ++F negative CR ++F negative CR ++ Reconversion to electricity ++ CCGTpower plant ++ CCGT-power plant ++ CCGT-power plant ++ CCGT-power plant ++ CCGT-power plant Demand Side Management Generation Management Flexible power plants CCGT: CR: combined-cycle gas turbine control reserve 1 : bigger storage capacities might be feasible abroad F: additional research required in particular 10

11 Load duration and residual load curves in 2032 for different regions Source: EFZN / Nakhaie 11

12 Engel, BSW Solar Distributed storage in combination with photovoltaics Useful operation modes relieve the electrical grid Charging in case of high energy infeed Reducing power Infeed Reduction of power infeed leads to an increase of local grid capacity 6 a.m. 12 p.m. 6 p.m. Distributed storage in combination with photovoltaics contribute to: Local voltage control in low voltage grids Global frequency control in the integrated European network Reduction of power gradients for conventional power plants Reduction of peak demand in the evening (subst. of peak power plants) 12

13 Costs of ancillary services Largest share: Balancing markets Increasing costs for Redispatch and Countertrading Black start capability shows a very small proportion of total costs (approx. 8 Mio. ) Costs of reactive power are continously decreasing since 2007; Volume in 2011: 27 Mio. Source: BNetzA Monitoringberichte 13

14 Responsibilities for the storage operation from a legal perspective Different kinds of storage operation Restrictions in relation to grid and storage operation General regulations for informational, accounting, legal, operational and ownership unbundling are to be used. Storage systems used by grid operators In general, grid operators can own a storage system to fullfil their duties (according to 3 Nr. 31 EnWG for gas storage) No unbundling in relation to the grid operation is required However, separate legal provisions have to be considered, especially for procuring balancing power So far, no assignment for grid operation seems to be possible Allocation of storage systems to energy generation or to sales/trade activities Unbundling requirements shall apply to the activities in question Storage operation as independent activity Storage devise is provided to third parties for their own purposes Unbundling requirements shall apply to other activities, partially less extensive than to energy generation or sales/trade activities 14

15 Thanks for your attention! Contact: Energie-Forschungszentrum Niedersachsen Andreas Becker Am Stollen 19A Goslar Telefon: ( ) Telefax: ( ) Internet: 15

16 Backup 16

17 Short version key results - complement Existing barriers, such as compensation arrangements in accordance with 12 of the EEG should be eliminated. Another critical point is the issue of exemptions from power grid charges. In connection with the unbundling rules for storage it is to clarify whether the energy storage can also be classified as a generation. Furthermore it should be clarified how the operation of power-to - gas -facilities could be classified. Financial government fundings for storage should be considered only as the last option, due to efficiency and cost reasons. Undesirable technical developments ("lock -in" effects) caused by one-sided funding of individual technologies must be avoided. 17

18 Level of Operational Security Theory: Determination of an optimal level would be desirable but not known Praxis: No special indicator / index exits describing the actual level of Operational Security Possible Indikatoren DISQUAL-Index Describing aspects of security of supply (e. g. SAIDI), still on a high level in Germany Number of short breaks According actual surveys (VIK) distinct rising tendency Power feed-in management pursuant to EEG Normaly regional problem in distribution networks Necessary engagements according 13 EnWG Redispatch, Countertrading, etc. 18

19 Analysis of existing barriers Unfavourable structures in the status quo Regulation 12 EEG und unlimited priority feed-in Quality element within the incentive-based regulation >3 minutes industry's investment dilemma Prices to marginal costs do not cover the long-term average cost Elimination of midday peak demand Abuse of foreign systems as an external effect Cost recovery by loading third-party networks (Installation of phase shifting transformers) Missing markets for systemically relevant services (e.g. inertia) Investment risks and waiting for bigger market reform 19

20 Short version key results 2/2 In order to ensure system security, the operational mode of storage units have to be adapted with regard to grid stability. Today s framework and the current market design do not provide sufficient long-term incentives for the use of system-stabilizing technologies. A vast reformation of the market design is essential to enable market-oriented and system-stabilizing use of storages and other flexibility options. 20

21 Measures for the utilization of surplus power by the example Strong-Wind-Region (2032) Source: EFZN / Nakhaie, Becker 21