Advancements in Grid Integration of Wind and Solar Power in the Western Interconnect World Renewable Energy Forum Forum Moderator, Brian Parsons May 17, 1:15 2:30 NREL is a national laboratory of the U.S. Department of Energy, Office of Energy Efficiency and Renewable Energy, operated by the Alliance for Sustainable Energy, LLC.
Three Electric Grids (Interconnections) in the U.S. Each interconnection must be balanced loads = generation 2
The West Has Only Two Large Markets (ISOs) 3 Map from the ISO/RTO Council
4 The West Has Many Small Balancing Areas Map from the ISO/RTO Council
5 WECC Territory Has Abundant Renewable Resources Photovoltaic Solar Resource Annual Average Wind Speed at 80 m Current legislated renewable portfolio standards in WECC result in around 11% wind and solar electricity by 2020.
Complex Regulatory, Planning, and Operational Frameworks Prudency, cost recovery, and cost allocation are state public utility commission jurisdictional. FERC regulates interstate commerce and, thus, wholesale bulk transactions Specific generator interconnection studies evaluate incremental upgrade needs Mostly contract path transmission rights Balkanized balancing area operations increase balancing challenges 6
Panel participants Brian Parsons NREL Debra Lew NREL Stephen Beuning Xcel Energy Bradley Nickell Western Electricity Coordinating Council (WECC) Victoria Ravenscroft Western Interstate Energy Board 7
How Do Wind and Solar Impact the Grid? Debbie Lew, Greg Brinkman, Eduardo Ibanez, NREL Steve Lefton, Nikhil Kumar, APTECH Gary Jordan, Sundar Venkataraman, GE Jack King, REPPAE WREF May 17, 2012 NREL is a national laboratory of the U.S. Department of Energy, Office of Energy Efficiency and Renewable Energy, operated by the Alliance for Sustainable Energy, LLC.
Western Wind and Solar Integration Study (WWSIS) What are the impacts of 35% wind and solar on the power system and conventional generators? Gas turbine PV CSP hydro Combined cycle Phase 1 report: http://www.nrel.gov/do cs/fy10osti/47434.pdf wind coal nuclear The worst week of three years 9
Wear and Tear Costs 10
11 Wear and Tear Cost Data Data results from analysis of APTECH on 400 coal and gas plants: Costs of hot, warm and cold starts Costs of ramping down to minimum output Forced outrage rate impacts Long term heat rate degradation Costs for 7 types of plants Coal small subcritical Coal large subcritical Coal super critical Gas combined cycle Gas large frame combustion turbine Gas aeroderivative combustion turbine Gas steam Plus best in class units
12 Cost of Cold Start-up Cold Start Cost Lower Bounds-Includes Outliers (Maintenance and capital cost per MW capacity) 400 300 200 100 0 1: Coal - Small Sub Critical 2: Coal - Large Sub Critical 3: Coal - Super Critical 4: Gas - CC [GT+HRSG+ST] 5: Gas - Large Frame CT 6: Gas - Aero Derivative CT 7: Gas - Steam Source: Steve Lefton, Intertek-APTECH, NREL Subcontract.
Increased Costs ($/MWh renewable) Ceiling on wear and tear costs Apply APTECH upper and lower bounds of wear and tear costs to WWSIS Phase 1 results for ceiling on wear and tear impacts Results show that cycling costs are up to $2 per MWH of renewables produced, or a reduction in value of the renewables of up to 2.4% 2.00 1.80 1.60 1.40 1.20 1.00 0.80 0.60 0.40 0.20 0.00 Increased Cycling Costs I10R I20R I2020R I30R Scenario Lower Bound Upper Bound 13
Emissions 14
Generation (MW) NOx emissions (lbs) Heat Rate (mmbtu/mwh) 15 EPA Continuous Emission Monitors Use measured hourly emissions from each fossil fuel plant in the U.S. for 2008 For each plant: Heat rate (and CO 2 emissions) as a function of generation Emissions (NO X, SO 2 ) as a function of generation Eliminate units with obviously clustered data 250 200 150 100 50 Ft St Vrain CC Unit 3 0 1760 1762 1764 1766 1768 1770 1772 1774 150 100 50 14 13 12 11 10 9 8 7 Front Range CC Unit 2 0 1760 1762 1764 1766 1768 1770 1772 1774 Hour of year Generation Min generation 6 0 50 100 150 200 250 Generation (MW) actual NOx predicted NOx
16 Startups Startup emission penalty in hours of equivalent full-load operation CO 2 NO x SO 2 Coal 1.2 1.0 0.8 Gas CC 0.3 6.1 n/a Gas CT 0.4 1.8 n/a Gas steam 0.9 0.0 n/a
17 WWSIS1 re-analysis Detailed startup, ramping, and part-loading emissions of NO x and CO 2 Generic emission rates applied by category to previously modeled dispatch Startups, part-load and ramping have relatively small impact compared to which unit is on the margin NO x (lbs/mwh) CO 2 (tons/mwh) Assuming flat emission curves 0.422 0.499 +considering partload emission rates +0.031 (+7.3%) -0.006 (-1.3%) +considering startup emissions -0.006 (-1.3%) -0.001 (-0.3%) +considering ramping emissions -0.011 (-2.7%) -0.001 (-0.2%) Total 0.436 (3.3%) 0.490 (-1.7%)
Next Steps 18
Reference Scenario (8% Wind, 3% Solar) 19 19
20 High solar (8% wind, 15% PV, 10% CSP) Wind Capacity (MW) 710 to 1,650 250 to 710 140 to 250 70 to 140 10 to 70 PV Capacity (MW) 104 to 200 64 to 104 36 to 64 12 to 36 0 to 12 CSP Capacity (MW) 186 to 200 142 to 186 105 to 142 84 to 105 64 to 84
High wind (25% wind, 4.8% PV, 3.2% CSP) Wind Capacity (MW) 710 to 1,650 140 to 710 110 to 140 80 to 110 10 to 80 PV Capacity (MW) 75 to 200 50 to 75 25 to 50 8 to 25 0 to 8 CSP Capacity (MW) 150 to 200 105 to 150 100 to 105 95 to 100 66 to 95 21
Hi mix (16.5% wind, 9.9% PV, 6.6% CSP) Wind Capacity (MW) 710 to 1,650 140 to 710 110 to 140 70 to 110 10 to 70 PV Cpacity (MW) 76 to 200 51 to 76 29 to 51 10 to 29 0 to 10 CSP Capacity (MW) 199 to 200 142 to 199 105 to 142 84 to 105 64 to 84 22
Normalized output 23 Aggregation Reduces Variability 1 Normalized daylight profile for increasing aggregation in southern CA PV for a partly cloudy day 0.9 0.8 0.7 0.6 0.5 0.4 0.3 0.2 One Plant Two plants Six Plants 25 plants So. Calif. 0.1 0 6:00 8:00 10:00 12:00 14:00 16:00 18:00
Thank you! Debbie Lew +1 (303) 384-7037 debra.lew@nrel.gov http://www.nrel.gov/wwsis 24
Prepared by Steve Beuning, 303-571-2711 Efficient Renewable Energy Integration World Renewable Energy Forum Denver, Colorado, USA 5/17/2012
Who We Are Xcel Energy NSP-Minnesota PSCo SPS NSP-Wisconsin * Percentages based on 2009 Ongoing Earnings Xcel Energy is dedicated to being an environmental leader at reasonable cost 26,000+ MW of generation Operating in 8 states No. 1 wind power provider No. 5 solar power provider 4000+ MW of wind 1375 MW of wind on AGC Customers 3.4 million electric 1.9 million gas 26
Outline PSCO Renewable Portfolio Overview Comparison of renewable integration costs Public Service of Colorado / Western Interconnection non-netted estimate Grid utilization discussion
PSCo s Wind & Solar Facilities in Colorado (Existing and Planned) ~2,200 MW by 2013 30 MW 550 MW 640 MW ~25 MW owned, rest purchased 35% - 45% Annual Capacity Factor 650 450 MW MW Known energy price Hedge against fossil fuel price volatility 240 MW Includes either PTC or ITC 85 MW of Solar 28
1/1/2011 2/1/2011 3/1/2011 4/1/2011 5/1/2011 6/1/2011 7/1/2011 8/1/2011 9/1/2011 10/1/2011 11/1/2011 12/1/2011 1/1/2012 2/1/2012 3/1/2012 4/1/2012 PSCO Wind as a Percentage of Obligation Load (1/1/2011 thru Present) 60% 10/9/2011 4 AM 55.6% 50% 6/21/2011 4 AM 45.4% 1/22/2012 6 AM 49.6% 40% 30% 20% 10% 0% 29 Hourly Monthly Annual
Renewable integration issues PSCO sees an opportunity to improve renewable integration efficiency in several areas: Reduced curtailments due to minimum load constraints Reduced curtailments due to transmission constraints Reduced cycling impacts on fossil plants Reduced costs for backup generators
Xcel Energy Utility Comparisons Utility and Market Region Wind MW / Utility MW / BA MW Max 30- minute MW negative wind ramp Integration cost per MWH renewable Total annual market cost Market cost per MW of demand PSCo / None 2,168 / 7,500 790 ~$4.50* N/A N/A SPS / SPP 1,100 / 5,500 273 Not Available ~$36M** ~$0.27** NSP / MISO 1,944 / 9,100 / 105,000 560 ~$0.33*** ~$226M**** ~$0.403**** - PSCO wind integration analysis ** - Estimated amounts *** - MISO integration cost per Iberdrola analysis **** - https://www.misoenergy.org/library/repository/communication%20material/financial%20information/2012-2014%20budget.pdf
PSCO integration cost savings: heuristic estimate Difference between high and low cost integration: ($4.50 - $0.33) = $4.17/MWH of renewable production PSCO 2013 forecast volume of renewable production: 7,319,000 MWH Integration savings bogey (not net of market cost): $30,520,230 PSCO 2013 forecast renewable production curtailments: 213,300 MWH Also assume curtailments mitigated by 20% at $55/MWH value, gives bogey adder: $2,343,000 Total integration (not net) benefit bogey: $32,863,230
Flex reserve aspect of EIM benefits: Flex MW BA as a stand-alone utility BA in an EIM with pooled diversity $$$ = savings Wind MW
Grid Utilization in the US Western Interconnection US States have established renewable portfolio standards which will lead to increased renewable energy supply by 2020 Analysis work compares business-as-usual with regional market operations in 2020 Benefit/cost efforts show promise for development of regional market efficiency NREL study estimates substantial annual benefit (not net of cost for market development)
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Western Electricity Coordinating Council Bradley Nickell Director of Transmission Planning WECC Western Interconnection Regional Transmission Expansion Planning (RTEP) World Renewable Energy Forum May 17, 2012 37
WECC Functions WECC s mission is to promote and foster a reliable and efficient Bulk Electric System 38 Non-Planning Functions Compliance Monitoring and Enforcement Standards Development Reliability Coordination Market-Operations Interface Operator Training WREGIS Planning Functions Loads and Resources Assessments Reliability Studies Transmission Expansion Planning
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10-Year Regional Transmission Plan 40 www.wecc.biz/10yrplan
10-Year Regional Transmission Plan Process Inputs Generation, Load, and Transmission Assumptions Public Policy Case Study Results Environmental and Water Information Stakeholder Input/Review Plan Reliability Analysis 41
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Renewable Procurement Trends In and Out of State RPS Energy for 2020 Expected Future WECC Wide: 79% of RPS energy served by in-state resources in 2020 Expected Future State/Province with RPS Goal or Mandate State/Province without RPS Goal or Mandate In-State RPS Out-of-State RPS 43
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10-Year Regional Transmission Plan How is Variable Generation Modeled? Synchronized hourly profiles (wind & solar) Planned VG additions based on extensive data research and stakeholder input Energy is must-take 45
Questions Bradley Nickell Director of Transmission Planning Western Electricity Coordinating Council 155 North 400 West Salt Lake City, Utah 84103 801.819.7604 bnickell@wecc.biz All information on the WECC 10-Year Regional Transmission Plan may be found at http://www.wecc.biz/10yrplan. 46