Experience with primary reserve supplied from energy storage system

Transcription

1 1 Experience with primary reserve supplied from energy storage system Rasmus Lærke, Vestas Wind Systems A/S Research and Innovation activities about energy storage integration in the electricity networks: Ongoing activities at national level and future needs Tuesday 26 th January 2016 Helsinki, Finland

2 Content Motivation Application & Installation Test Results Conclusions & Perspectives 2

3 Vestas research programme on energy storage started in 2010: Motivation: Identify value-add from wind power + energy storage. Activities: Identify best match of applications (revenue) and ESS technology. Develop competence on optimal control w.r.t. ES life-time and ratings. Select & qualify suppliers. Verify life-time models. Demonstrate integration, functionality and economy.

4 Wind Power Plant with Energy Storage Energy Storage Management System 4 x 3MW 1.6MW x 0.25h

5 Lem Kær wind farm, substation & energy storage system

6 Forecast Error Reduction Idea: Reduce financial penalties for not meeting generation commitment. Reality: Aggregation of several wind plants over a geographical spread allows similar gains.

7 Ramp Rate reduction / power smoothening (dp/dt control) Idea: For power quality in weak networks, keep output variations from the combined Wind/ESS plant below a threshold. Reality: no payment for service; fast wear-out.

8 Load Shifting Energy Arbitrage Idea: Store energy when price is low and sell when price is high Reality: Tariff cycle: 2 times / 24h - Tariff diff < 20 / MWh Long time between real events Losses in the Energy Storage under charge / discharge and idling.

9 Cost: storage life-time Modelling: Determine ESS ratings to warrant life-time for a given mission profile CAPEX (MW & MWh ratings + fixed cost) OPEX (efficiency + capacity degradation + standby + replacements + availability) The most meaningful single number expressing battery lifetime is the allowed no. of charge/discharge cycles of a given charge depth at a certain temperature.

10 The potential services a Wind Power Plant augmented by embedded Energy Storage can provide Primary Reserve Ancillary services Primary Reserves Secondary Reserves Tertiary Reserves Black Start Load Shifting Energy Arbitrage Transmission Curtailment Forecast Error Reduction Ramp Rate reduction (dp/dt control) Voltage Control Islanding (Transmission deferral) NPV (%) relative to best case (GFR) Results from a 2009 Vestas study on a 66MW wind plant in three different locations (electricity markets).

11 Energy Storage installation ESS1: 53 container 0.4MW / 0.25h LiFePO 4 BMS Air-con Fire suppression Heat exchanger Power electronic converter Transformer 0.48/10kV 10kV circuit breaker ESS2: Power electronic converter Transformer 0.48/10kV Heat exchangers ESS2: 53 container 1.2MW / 0.25h Li 4 Ti 5 O 12 BMS Air-con Fire suppression

12 Power System Stability Source: NationalGrid, U.K.

13 Frequency support. Primary reserve. The Danish TSO, Energinet.dk, defines the primary reserve product as: Regulation must be supplied at a frequency deviation of up to +/-200 mhzrelative to the reference frequency of 50 Hz. This will normally mean in the Hz range. A deadbandof +/-20 mhzis permitted. The reserve must as a minimum be supplied linearly and be fully activated within 30 seconds in the event of a frequency deviation of +/-200 mhz. be able to deliver a constant level of active power (dicharge) for 15 minutes. After another 15 minutes it should be able to repeat the delivery. - Auctions take place at 15h00 the day before delivery, and bids are supplied in 6 blocks of 4 hours each. - Upwards and downwards regulation (under- and over-frequency, respectively) are separate, ie. asymmetrical bids are permitted. - For an ESS up-regulation-only provider, currently no requirements exist to the level and direction of the power flow when not delivering upwards regulation.

14 Board of Directors Bert Nordberg, Chairman Born: 23 March 1956 Nationality: Swedish Resident: Sweden Position: President & CEO, Sony Mobile Communications (Sweden) Test results Jørn Ankær Thomsen Born: 17 May 1945 Nationality: Danish Resident: Denmark Position: Attorney at Law and partner, Gorrissen Federspiel (Denmark) Lars Josefsson, Deputy Chairman Born: 31 May 1953 Nationality: Swedish Resident: Sweden Position: Independent consultant Kurt Anker Nielsen Born: 8 August 1945 Nationality: Danish Resident: Denmark Position: Director Carsten Bjerg Born: 12 November 1959 Nationality: Danish Resident: Denmark Position: CEO and Group President of Grundfos Management A/S (Denmark) Knud Bjarne Hansen* Born: 26 March 1952 Nationality: Danish Resident. Denmark Position: Senior Vice President, Vestas Wind Systems A/S (Denmark) Eija Pitkânen Born: 23 April 1961 Nationality: Finnish Resident: Finland Position: Vice President, Head of Corporate Responsibility, Telia Sonera (Sweden) Kim Hvid Thomsen** Born: 8 August 1963 Nationality: Danish Resident. Denmark Position: Industry technician and Senior Shop Steward, Vestas Manufacturing A/S (Denmark) Håkan Eriksson Born: 8 April 1961 Nationality: Swedish Resident: Australia Position: Head of Ericsson Australia, New Zealand and Fiji (Australia) Michael Abildgaard Lisbjerg** Born: 17 September 1974 Nationality: Danish Resident: Denmark Position: Skilled worker - Production & Shop Steward, Vestas Manufacturing A/S (Denmark) Jørgen Huno Rasmussen Born: 25 June 1952 Nationality: Danish Resident: Denmark Position: President and CEO, FLSmidth & Co. A/S (Denmark) Sussie Dvinge Agerbo* Born: 5 November 1970 Nationality: Danish Resident: Denmark Position: Management Assistant, Vestas Wind Systems A/S (Denmark) *) Elected by company employees **) Elected by Group employees

15 Danish TSO Primary Reserve approval test 15 minute activation >85% round-trip efficiency 1.4MW Power [kw] Power [kw] -1.6MW Discharge SoC1 [%] SoC2 [%] Charge Time [sec] 0 min 15 min 30 min State of Charge SoC [0/00] 90% SoC P_Elspec_ESS1+ESS2+AUX SOC 1 SOC 2 10% SoC

16 Frequency recordings Jan 1 st 2013 May 31 st x 106 No samples vs. frequency (1 sec update) 6 5 Number of samples Frequency Up-regulation Hz Our recordings have shown that continuous periods of 15 minutes of under-frequency (below Hz) only occur in average 50 times per month (ie. <2%).

17 Charging controller

18 Data recorded at site Frequency dev. [mhz] Primary Reserve from Energy Storage. 25th March ES power [MW] min limit reached State of charge Time [h]

19 Data recorded at site Accum. duration of low frequency periods pr. month Calculated energy [MWh] vs. frequency pr. month Recordings from Duration [hours] Energy [MWh] Month > > > > > > >49.86 Frequency [Hz] Month > > > > > > >49.86 Frequency [Hz] Discharged during upward regulation 0.32 MWh/day Charged 0.60 MWh/day Absorbed for auxiliary power consumption 0.35 MWh/day Duration of frequency below 49.98Hz 16% Under-frequency energy demand 0.35 MWh/day

20 Primary reserve tariff evolution in Western Denmark 140 Tariff for ENDK1 primary reserve up-regulation Tariff [EUR/MWh] Days Jan 1 st 2013 May 31 st 2015

21 Net present value of green field investment 0,2 NPV, per-unit vs years ,2-0, ,6 140 Tariff for ENDK1 primary reserve up-regulation ,8 Tariff [EUR/MWh] Days -1

22 Simulation power/energy ratio for primary reserve Simulations are based on 1 year grid frequency data (2012). ESS Capacity (discharge time with ESS full power ) PFR AVA [%] 15 min discharge time 100,00 10 min discharge time 100, min discharge time 100,00 6 min discharge time 100,00 5 min discharge time min discharge time min discharge time min discharge time min discharge time min discharge time min discharge time PFR service availability [%] ESS capacity [min]

23 Wind power plant + energy storage applications Up-regulation by energy storage system Inertial Response + Primary Reserve Down-regulation by wind power plant Power oscillation damping Pref_AWPP_kW P_Elspec_WPP_kW P_Elspec_WPP_kW Power smoothening From : +

24 Conclusions and Perspectives 1. The TSO has approved storage units for primary reserve market participation. 2. Apparently the only installation of its kind in Scandinavia. Commercial operation for 3 years. 3. The 15-minute constant power discharge effectively sizes the capacity. Only used for up-regulation. 4. The observed network frequency excursions are very modest Low utilisation of storage (2%). 5. Effective full-cycle efficiency is 50% (30% incl. aux power losses). 6. Specific algorithm developed and approved for control of storage charging. 7. If symmetric bids are required, SoC controller must be adapted (and business case erodes). 8. Recent reserve power tariff reduction erodes business case. 9. Storage cost reduction required and expected. Thanks to:

25 Conclusions and Perspectives 1. Installed storage capacity may be reduced if requirements were matched to actual frequency excursions. This would increase utilisation rate. Main circuit efficiency should then be optimised. 2. Blending other ancillary services may increase earnings. 3. Wider aggregation of turbines/plants with common storage facility to reduce ratings. 4. Ancillary services market development new technologies new markets 5. Detailed technical performance specifications necessary for any evaluation of feasibility of ancillary service provision from wind power plants - with/without storage! Thanks to:

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