Wind Workshop. Technical Characterization: Dependable Capacity & Firm Energy 10:00-10:30am

Transcription

1 Wind Workshop Technical Characterization: Dependable Capacity & Firm Energy 10:00-10:30am

2 Objective of this session: Understand BC Hydro s definitions and calculation methodology of dependable capacity Understand other definitions and calculation methodologies Formulate new approach?

3 Agenda Dependable Capacity Other jurisdictions (PJM,CallSO, NYISO) BC Hydro definition and methodology Geographic Smoothing Firm Energy Other jurisdictions (CallSO, NYISO) BC Hydro definition and methodology Monthly energy profile and coincident peak

4 Capacity Credit PJM From PJM News Release April 24, 2003: -Based on a wind farms actual performance -Calculated as three-year rolling average of a units output during Peak hours(3 pm and 6 pm) during June, July, August -Class average is 20%

5 Capacity Credit California From Study of Renewables Integration Costs for California s RPS (Phase 1) Based on California ISO Plant Information for wind farms in Altamont, San Gorgonio and Tehachapi Calculated as the Effective Load Carrying Capacity (ELCC) of wind farms Wind in the Altamont area contributed ELCC of 26%, San Gorgonio 24% and Tehachapi 22% The California class average is 24%

6 Capacity Credit New York From NYISO/NYSERDA Wind Study Unforced Capacity (UCAP) of wind farms when load exceeds 90% of peak load was used to estimate the ELCC This modified UCAP ranged between 3% and 23% The modified UCAP was low because New York wind farms have low outputs during summer evenings, which are the highest load times in the area

7 Capacity Credit PacificCorp Effective Load Carrying Capability - amount of load that can be supported by a wind unit while holding some risk measure constant (Energy not served) - for 100 MW Wind unit, contribution to load ranged from % - suggested using 20% contribution to load (study based on limited data)

8 Capacity Credit Colorado Colorado PUC s decision regarding Xcel Energy - wind farm provides ~30% equivalent European Wide study by Giebel - suggests ~19% equivalent

9 BC Hydro Definition - Dependable Capacity A generating plants dependable capacity is the maximum megawatt output it can reliably produce when required, assuming all units are in service Reliably Produce: means availability coincident with system peak with high confidence level

10 BC Hydro Definition - Dependable Capacity Dependable Capacity is affected by factors external to the plant I.e. streamflow conditions; fuel supply constraints; wind Not affected by: Forced outages not included - in planning reserves Planned outages not included - assumed to be scheduled around winter peak

11 BC Hydro Definition - Dependable Capacity For annual supply-demand balance: 3 hours in peak load period of weekday during the continuous two weeks of cold weather Pragmatic definition for calculation capacity available during 2 consecutive months of low flow/fuel supply for the period of concern (i.e. 3 hours) based on 85% confidence level.

12 Dependable Capacity - calculation methodology Major Generating Plants with upstream storage: - 85% confidence level of assumed 50 years stream flows Existing IPP projects: - based on actual performance (85% confidence level ) Planned IPP projects: - based on their contracted capacity Projects in Resource Options Database: - some projects have site specific information available (Site C, Rev5), others base on class average Dependable Capacity Factors

13 BC Hydro Methodology for Wind Dependable Capacity Factor = dependable capacity/installed capacity class average percent Used data (Dec & Jan) from BC Hydro monitoring sites Moving minimum across 3-hour intervals (using average hourly data) Determine wind speed that is exceeded 85% of the time Use turbine power curve to determine the power Fraction of this value compared to nameplate capacity is DCF

14 DCF Results for BC Hydro Sites Average 85 % confidence Mt Hays 0.00 Mt Wartenbe 0.00 Aasen 0.00 Bear Mountain 0.00 Sugar Loaf 0.55 Ashcroft South 0.00 Rumble Ridge 0.05

15 Capacity Summary Capacity Equivalent other utilities 0 to 30% California 24% New York 3% to 23% PacifiCorp 20% Xcel 30% Dependable Capacity BC Hydro sites 0 to 55% Class Average 0%

16 Capacity Credit Vancouver Island From BC Hydro Rumble Ridge Meteorological Tower and BC Hydro Load Profile The ELCC of wind farms can be accurately calculated with an Expected Energy not Served (EENS) study Otherwise, the ELCC can be estimated using the modified (UCAP) methodology of the NYISO Study A Rumble Ridge farm with an annual capacity factor of 30% has a 40% capacity factor at times of peak loads The modified UCAP is high because Vancouver Island winds are strongest during winter, when BC loads peak

17 Wind Hydro Correlation Percent of Peak Jun Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May B.C. Reservoir Storage Wind Speed at Port Hardy Peak Load on Vancouver Island

18 BC Hydro Methodology for Wind Using the BC Hydro methodology for wind dependable capacity and Sea Breeze data The dependable capacity of a typical wind farm on Vancouver Island is 3% The dependable capacity of wind farms in a small region of Vancouver Island is 14% The dependable capacity of wind farms over the entire island would be greater still With PJM or NYISO methodology, the capacity credit would be 40%

19 Geographic Smoothing Concept instead of evaluating Dependable Capacity of an individual site, consider for a number of sites Journal of Geophysical Research (May 2003) - power output average over 1, 3, 8 stations - Intermittency of wind energy from multiple wind farms less than from a single farm. Example using BCH data: Rumble Ridge (VI), Mt Hays (Prince Rupert),and Bear Mountain (Peace)

20 BC Hydro Definition - Energy Capability Average energy - expected annual energy for hydro is based on average water conditions average energy for dispatchable thermals incorporates economic dispatch Small hydro, wind, wave etc.: Currently not enough information to discern firm & average in portfolios Firm energy - what a project can generate annually on an assured basis based on historic low water for BC Hydro projects for thermals - based on installed capacity, fuel supply & unit availability

21 Firm Energy other jurisdictions -Only an issue for Hydro systems that are energy constrained. Thermal systems are capacity constrained so do not usually consider firm energy. -BPA : Firm energy based on critical water years -North West Planning Council recently introduced standard to plan for energy based on 85% quantile.

22 Energy Capability of Wind Annual wind farm output has a standard deviation of about 7% 93% of the average annual output is exceeded by 85% of years Since wind has low annual variation, it can serve as energy insurance for the critical water years in the BC Hydro system

23 Monthly Energy Profile and load 12% 10% 8% 6% 4% 2% Peace Van Island Load 0% Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec % of Annual Energy

24 Monthly Energy Profile and load 120% Peace Van Island Load 100% 80% 60% 40% 20% 0% Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec % of of max month

25 Summary of Discussion: Dependable Capacity Firm Energy