STORAGE EVALUATION IN CONGESTED GRIDS

Transcription

1 STORAGE EVALUATION IN CONGESTED GRIDS Stefan Kippelt (ie3), Benjamin Böcker (EWL)

2 Introduction Increasing demand for grid expansion measures Feed-in of renewable energy sources (mainly PV and wind) Increasing decentralization of feed-in Today s storage operation primarily driven by Taking advantage of price spreads (Spot market, intraday market, increasing own consumption) Provision of ancillary services (Control reserves, black start capacity etc.) Grid operators begin to investigate BESS for grid purposes stochastics

3 Prequel: ETG Study BESS in Distribution Grids Release of ETG Study Investigation of various application cases of storage systems in distribution grids Own consumption optimization Spot market trading Provision of ancillary services Substitution of grid expansion measures 1400% % 1000% 800% 600% 400% 200% 0% Leitungslänge Q95% Niederspannung 0,4 kv Leitungslänge Q99% Leitungslänge Q95% Mittelspannung 10 kv Leitungslänge Q99% Leitungslänge Q95% Mittelspannung 20 kv Leitungslänge Q99%

4 Prequel: ETG Study BESS in Distribution Grids Release of ETG Study Investigation of various application cases of storage systems in distribution grids Own consumption optimization Spot market trading Provision of ancillary services Substitution of grid expansion measures Key questions: Is a combined storage operation economically efficient? How should these storage operations be compensated? What kind of policy can stimulates an efficient storage operation?

5 Modellig Approach: Storage Evaluation in Congested Grids Economic Setting BESS Market Role Distribution Grid Generation of time series Investment decisions Optimization Model Congestions and free capcity Evaluation of technical measures BESS installation Grid expansion Curtailment Voltage Control menasures

6 Selection of representative distribution grids Selection of Voltage Level Low Voltage Medium Voltage 10 kv & 20 kv Grid configuration Line diameters Line Length Stefan Kippelt Berlin,

7 Frequency of Occurrence CHAIR FOR MANAGEMENT SCIENCE AND Selection of representative distribution grids Selection of Voltage Level Grid configuration Line diameters Häufigkeit 20 [%]% 10 Low voltage Niederspannung 0,4 kv Anteil Kabel Anteil Freileitung Line Length ,5 1 1,5 [km] 2,5 Leitungslänge Line Length Stefan Kippelt Berlin,

8 Grid Capacity in kw Übertragbare Wirkleistung [kw] CHAIR FOR MANAGEMENT SCIENCE AND Limiting Curve Analysis Calculation of a grid s capacity without violation of operatational limits 250,00 200,00 kw 150,00 100,00 x Q 95% Q 99% Example: Low Voltage 0,4 kv NAYY 4x150SE 50,00 0,00-50,00-100,00 Voltage Limits: ± 4% VDE-AR-N 4105 ( 3%-Cirteria ) -150,00 Center of gravity load 50% -200,00-250,00 0,00 0,25 0,50 0,75 1,00 1,25 1,50 1,75 2,00 2,25 2,50 Leitungslänge [km] Line Length in km Center of gravity RES 55% Stefan Kippelt Berlin,

9 Load CHAIR FOR MANAGEMENT SCIENCE AND Generation of Time Series Generation of time series of grid utilization Loads: Low Voltage: Smart-Metering Data Medium Voltage: Standard Load Profiles PV Feed-in: local Weather data Scaling of Loads of Generation Loads: 50 % of max. capacity PV: Variation between 110 % and 250 % of max. capacity max. load t max. back-feed Storage / Curtailment Stefan Kippelt Berlin,

10 Power CHAIR FOR MANAGEMENT SCIENCE AND Evaluation of Investment Alternatives BESS Needed Capacity Needed Power max. Last Alternatives Curtailment Curtailed Energy Costs of compensation Netzausbau Benötigte Leistungskilometer Storage / Curtailment t max. back feed Benötigte Abgänge Spannungsregelung rons / Spannungslängsregler Technisch möglich? Voltage Level Costs 2015 Costs 2023 Life Time 525 /kwh 200 /kwh MS / NS 15 a 125 /kwh 100 /kwh Stefan Kippelt Berlin,

11 Evaluation of Investment Alternatives BESS Benötigte Speicherleistung Benötigte Speicherkapazität Umbau zu Tripelnetz Alternatives Abregelung Abgeregelte Energiemengen Kosten für Entschädigung Line Expansion Required Length Required Feeders Spannungsregelung rons / Spannungslängsregler Technisch möglich? Netzebene Maßnahme Kosten Lebensdauer NS MS Alle ½ P PV ½ P PV Kabel + Erdarbeiten 80 T /km 40 a Umrüstung zur rons 30 T 20 a Kabel + Erdarbeiten 110 T /km 40 a Abgangsfeld 85 T 40 a Spannungsregler 300 T 20 a Abregelung PV aktuell 31 ct/kwh - Abregelung PV ct/kwh - Stefan Kippelt Berlin,

12 Übertragbare Wirkleistung [kw] CHAIR FOR MANAGEMENT SCIENCE AND Evaluation of Investment Alternatives BESS Benötigte Speicherleistung Benötigte Speicherkapazität Alternatives Abregelung Abgeregelte Energiemengen Kosten für Entschädigung Netzausbau Benötigte Leistungskilometer Benötigte Abgänge Voltage Control Tab Changing Transformer / Voltage Controller Technically feasible? Stefan Kippelt Berlin, ,00 200,00 kw 150,00 100,00 50,00 0,00-50,00-100,00-150,00-200,00-250,00 0,00 0,25 0,50 0,75 1,00 1,25 1,50 1,75 2,00 2,25 2,50 Leitungslänge [km] Netzebene Maßnahme Kosten Lebensdauer NS MS Alle x Q 95% Q 99% Kabel + Erdarbeiten 80 T /km 40 a Umrüstung zur rons 30 T 20 a Kabel + Erdarbeiten 110 T /km 40 a Abgangsfeld 85 T 40 a Spannungsregler 300 T 20 a Abregelung PV aktuell 31 ct/kwh - Abregelung PV ct/kwh -

13 Modellig Approach: Storage Evaluation in Congested Grids Economic Setting BESS Market Role Distribution Grid Generation of time series Investment decisions Optimization Model Congestions and free capcity Evaluation of technical measures BESS installation Grid expansion Curtailment Voltage Control menasures

14 Optimization Model Objective Function / Overview Minimizing cost for grid and storage operator min C investment + C compensation R market Investment costs for the grid and the storage Grid expansion (binary decision) Storage investment (capacity and volume individually) Compensation for curtailment Additional revenues from spot market trading

15 Optimization Model Main Restrictions Storage operation under grid constraints charging: y S,C t R C t + b grid R ad Storage discharging: y S,D t R D t + b grid R ad + y cur,s t Capacity: R L,S t.. L S t + 1, u S = L S t, u S + y S,C t, u S η S u S y S,D t, u S R V,S t.. L S t, u S V S u S R K,D t, u S.. y S,D t, u S K S u S R K,C t, u S.. y S,C t, u S K S u S

16 Optimization Model Overview Scenario Data Grid Data (local Feed-In) Storage Costs Grid Expansion Costs Market Prices Optimization Model Optimal storage investment and operation Trade-Off: Grid investment, storage investment and curtailment Willingness to pay to the storage operator

17 Scenario Data Base Case Based on NEP 2013, Second Draft (Reference year 2011) scaled up according to 2023B Demand profiles: ENTSO-E, Renewable feed-in: EEX and local weather data (adjusted for changed full load hours) Possibility of curtailment (especially PV) Compensation for curtailment: Current average infeed tariff (33 ct/kwh) Unbundling and contract law Financial framework (interest rate)

18 Costs and Market Base Case Storage Investment: (100 /kw, 200 /kwh, 20 years, 5.7%, 2% fixed o&m) 95% Efficiency Grid investment: 80 k /km (dena distr. grid study) (40 years, 6.4%) Market Spot Price Simulation: Hybrid-Model (EWL) Two Step Simulation Fundamental price and additional stochastics According scenario data Mean Price: 42.6 /MWh (51.1 /MWh in 2011) Number of neg. prices 233h (16h in 2011)

19 Exemplary Result Base Case Key Input Parameters: 0.3 km, 30% Excess Feed-In PV, Compensation ø infeed tariff) Optimal Dimensioning avoid grid expansion and curtailment Usable Capacity 38 kwh 88 kwh Power 38 kw 55 kw Load duration 1.0 h 1.6 h

20 Sensitivities Data Length of lines (low voltage grid) 0.1 km up to 1.6 km, Median: 0.3 km // 95% Quantile: 1,1 km // 99% Quantile: 1,6 km Excess Feed-In PV (in comparison to avoid curtailment) 10% to 150% Market (Sensitivity I): Storage operation for grid purposes only Storage operation for grid purposes and spot markets Compensation Payments (Sensitivity II): Curtailment Compensation Current average of 33 ct/kwh feed-in tariff Current feed-in tariff of 13 ct/kwh Spot price No compensation No curtailment allowed

21 Optimal Decisions Market Sensitivity grid purposes only spot market + grid purposes Optimal Investments: Grid Grid + Storage Storage Storage + Curt. Curtailment only

22 Optimal Decisions Compensation Sensitivity Current average Current spot market + grid purposes Grid Grid + Storage Storage Storage + Curt Curtailment only Spot-Price No curtailment No compensation

23 Summary Optimal investment decision Highly dependent on: grid length and excess feed-in of PV Regulatory framework (unbundling, compensation payments) Value of storages: Storage investment only for grid purposes Only in limited cases (Line length >700m, excess feed-in PV 1.5 to 2.3) Only very small-sizes storages Storage investment for grid purposes and spot-markets leads to more reduced grid expansion costs

24 Outlook Implementation of Reserve Market see upcoming paper More sensitivities calculated: Voltage control storage investment costs Further advantage of storages: Mobility ( Option Value ) Possibility to avoid or shift grid investment Possibility to optimize curtailment payments (grid perspective)

25 Optimal Decision Market Sensitivity (with voltages control) Only grid pursoses spot market / grid purposes Grid Voltage Control Storage Storage + Curt. Curt. only

26 Optimal Decision Li-Ion Costs Low: 100 [ /kw], 200 [ /kwh] High: 120 [ /kw], 500 [ /kwh] Grid Grid + Storage Storage Storage + Curt. Curt. only