Power Systems & Energy Course Large-Scale Wind Integration: Power System Operations Jason MacDowell Overview of Power System Operations © 2016 General Electric International, Inc All rights reserved Not for distribution without permission Impact of High Wind Penetration on System Operation and Power Markets • Emerging issue in many parts of the world as wind power becomes a significant portion of the overall generation mix • Many lessons learned in Europe (painful but valuable) • Discuss results from detailed analysis of several regions in North America (mostly from Western USA, New York, and California) • Share ideas on how to evaluate and quantify the impact of wind power on the overall power grid • Share lessons learned – and advice looking forward • Start with basic concepts of grid operation and how wind power fits in © 2016 General Electric International, Inc All rights reserved Not for distribution without permission What is a Control Area? FERC Definition An electric power system or combination of electric power systems to which a common automatic control scheme is applied in order to: • match, at all times, the power output of the generators within the electric power system(s) and capacity and energy purchased from entities outside the electric power system(s), with the load in the electric power system(s); • maintain, within the limits of Good Utility Practice, scheduled interchange with other Control Areas; • maintain the frequency of the electric power system(s) within reasonable limits in accordance with Good Utility Practice; and • provide sufficient generating capacity to maintain operating reserves in accordance with Good Utility Practice © 2016 General Electric International, Inc All rights reserved Not for distribution without permission © 2016 General Electric International, Inc All rights reserved Not for distribution without permission Control Area Obligations • Meet its area instantaneous demand, Interchange Schedule, Operating Reserve, and reactive resource requirements • Provide its frequency bias obligations • Balance its Net Actual Interchange and Net Scheduled Interchange • Use tie-line bias control (unless doing so would be adverse to system or the Interconnection reliability) • Comply with Control Performance and Disturbance Control Standards • Repay its Inadvertent Interchange balance How is this done? How are grid operations affected by wind power? © 2016 General Electric International, Inc All rights reserved Not for distribution without permission California Load – Average Day in July 2003 50 Load 45 45 40 40 35 Cumulative MW 35 GW 30 25 20 Gas Turbine Variable Imports Pump Storage Hydro Hydro 30 Combined Cycle 25 Fixed Imports 20 Steam 15 15 10 10 Biomass Geothermal 5 0 Hour 12 18 Nuclear More Flexible for Dispatch 50 24 © 2016 General Electric International, Inc All rights reserved Not for distribution without permission System Operation Process - Overview Day Ahead • • • Prepare load forecast (Total MW load for each hour of the day) Commit units that will run to serve the load (accounts for uncertainty) Preliminary dispatch schedule for each unit (by hour) Units with long startup times are “committed” for operation during the next day Hour Ahead • • Perform hour-ahead load forecast Adjust hourly dispatch for committed units as required to match actual load Real Time • • • Load-following (typically, dispatch is adjusted at 5-minute intervals) Adjustments based on “economic dispatch”, using marginal costs or competitive bids Regulation (fast adjustments of MW to regulate frequency and intertie power flows) © 2016 General Electric International, Inc All rights reserved Not for distribution without permission Conceptual Timeline for Day-Ahead Unit Commitment Day of Operation 35 Load GW 30 25 20 15 -24 am Load + Unit Data Received 12 am -18 -12 -6 Hours 12 pm 12 am Morning Load Rise 11 am Unit Commitment Completed SCUC 12 am 18 24 pm Peak Load 12 pm 12 am GFS Updates (6-hr period) Wind Forecast 29 hrs 44 hrs © 2016 General Electric International, Inc All rights reserved Not for distribution without permission What happens when Wind Generation is Added? Note that this example assumes a large amount of wind generation 50 Load Wind 45 40 35 12.5 GW wind generation on a system with about 55 GW peak load GW 30 25 20 15 10 0 12 Hour 18 24 © 2016 General Electric International, Inc All rights reserved Not for distribution without permission 10 Operating Cost Benefits in WECC 50 Operating Costs ($ Billions) 40 30 20 10 No Wind Preselected Wind 10% Wind 20% Wind 20/20% Wind 30% Wind In-Area Scenario, SOA Forecast © 2016 General Electric International, Inc All rights reserved Not for distribution without permission 31 Incremental Operating Cost Benefits in WECC 90 Value of Wind Power, $/MWh (Decreases slightly as wind penetration increases) Savings ($/MWh) 85 80 75 70 Preselected Wind 10% Wind 20% Wind 20/20% Wind 30% Wind In-Area Scenario, SOA Forecast © 2016 General Electric International, Inc All rights reserved Not for distribution without permission 32 Grid maneuverability decreases as wind penetration increases I10R 15,000 I20R 15,000 10% Wind Energy MW Range or MW/min Rate 5,000 -5,000 Ramp Up (MW/min.) Ramp Down (MW/min.) Range Up (MW) Range Down (MW) -10,000 -15,000 -20,000 -25,000 4/10 20% Wind Energy 10,000 5,000 -5,000 -10,000 -15,000 Ramp Up (MW/min.) Ramp Down (MW/min.) Range Up (MW) Range Down (MW) -20,000 4/11 4/12 4/13 4/14 4/15 -25,000 4/10 4/16 4/11 4/12 4/13 4/14 4/15 4/16 I30R 15,000 Week of April 10, Spring Season • Load levels are typically low • Wind generation is typically higher in spring than other seasons • Wind plant output is typically greater at night • Grid has difficulty operating at “minimum load” 30% Wind Energy 10,000 MW Range or MW/min Rate MW Range or MW/min Rate 10,000 5,000 -5,000 -10,000 -15,000 Ramp Up (MW/min.) Ramp Down (MW/min.) Range Up (MW) Range Down (MW) -20,000 -25,000 4/10 4/11 4/12 4/13 4/14 © 2016 General Electric International, Inc All rights reserved Not for distribution without permission 4/15 4/16 33 Dealing with Uncertainty • Basic options are to increase reserves or demand response • Increasing reserves – Commit additional generation so that load will never be interrupted – Need to it 100% of the time, because you not know when the reserves will be required • Demand response – Interrupt or reduce load occasionally, as need arises – A paid ancillary service © 2016 General Electric International, Inc All rights reserved Not for distribution without permission 34 Contingency Reserve Shortfall 1,200 60 Curtailed Energy (GWh) 1,000 50 800 40 600 30 400 20 200 10 Contingency Reserve Shortfall (GWh) Curtailed Energy (GWh) Contingency Reserve Shortfall (GWh) No Wind 10% Wind 20% 20/20% Wind Wind +0% +5% +10% +15% +20% +25% 30% Wind & Increased Reserves as % of Wind Forecast © 2016 General Electric International, Inc All rights reserved Not for distribution without permission 35 Cost of Increasing Reserves 100,000 Average cost of increased reserves ($/MWh) 80,000 Incremental cost of increased reserves ($/MWh) 60,000 40,000 20,000 +5% Wind Forecast +10% Wind Forecast +15% Wind Forecast +20% Wind Forecast +25% Wind Forecast © 2016 General Electric International, Inc All rights reserved Not for distribution without permission 36 Dealing with Wind & Solar Variability • Balance of generation portfolio (i.e., dispatchable generation) must respond to variations in net load – Room to maneuver up or down, i.e., range (MW) – Speed to maneuver up or down, i.e., ramp rate (MW/min) • Additional duty will have associated O&M costs • Markets should encourage BOP generation to maintain and/or increase flexibility – Decrease minimum turndown – Increase ramp rate capability – Decrease minimum down time – Increase quick start • Operating procedures should mitigate impact – Sub-hourly schedules © 2016 General Electric International, Inc All rights reserved Not for distribution without permission 37 Benefits of Coal Flexibility Operating Cost Increase ($M) 160 120 80 40 50% Minimum 60% Minimum 70% Minimum © 2016 General Electric International, Inc All rights reserved Not for distribution without permission 38 Impact on Coal of Increasing Penetration 100 8,760 90 7,884 80 7,008 70 6,132 Starts Capacity Factor 60 5,256 Revenue Hours 50 4,380 40 3,504 30 2,628 20 1,752 10 876 Hours of Operation per Unit # of Starts per Unit, Capacity Factor (%), Revenue (k$/GWh) Coal Plants per Unit, Local-Priority Scenario Pre-selected 10% 20% 30% © 2016 General Electric International, Inc All rights reserved Not for distribution without permission 39 Impact on Combined Cycle 100 8,760 90 7,884 80 7,008 70 6,132 60 Starts 5,256 Capacity Factor 50 Revenue 4,380 Hours 40 3,504 30 2,628 20 1,752 10 876 Hours of Operation per Unit # of Starts per Unit, Capacity Factor (%), Revenue (k$/GWh) Combined Cycle Plants per Unit, Local-Priority Scenario ©Pre-selected 2016 General Electric International, Inc All rights reserved Not 20% for distribution without permission 10% 30% 40 Other Trends Requiring Generation Flexibility • Anticipated addition of inflexible generation • New Nuclear • New IGCC • New Geothermal and Biomass • Ongoing loss of flexibility in existing fleet • Retirement of oil steam and small coal • Restrictions on hydro • Restrictions on emissions © 2016 General Electric International, Inc All rights reserved Not for distribution without permission 41 Lessons Learned © 2016 General Electric International, Inc All rights reserved Not for distribution without permission 42 Market evolution: Cost recovery will be based less on energy A/S Wind/solar depress prices A/S Capacity Capacity Energy Energy Source: Rothleder, CAISO 2016 Low VER penetration © 2016 General Electric International, Inc All rights reserved Not for distribution without permission © 2016 General Electric Company All Rights Reserved High VER penetration 43 Lessons Learned Impediments Lack of transmission Lack of control area cooperation Inflexibility due to market rules and contracts Unobservable DGs Inflexible operation strategies during light load & high risk periods System cost • • • • • Unserved Energy RPS miss Higher COE Higher Emission Higher O&M System Cost • • • • • Impediments Enablers • • Forecasting Thermal fleet • • More spatial diversity Renewable + DG + Demand A/S Grid-friendly renewables • – Higher quick starts – Deeper turn-down – Faster ramps Enablers Renewable penetrations, % © 2016 General Electric International, Inc All rights reserved Not for distribution without permission 44 Conclusions • The question isn’t “How much can you install?” • The question is “What you need to to integrate it?” • Modifications to operations, planning, and infrastructure may be needed High penetrations may require: • Cooperation between Balancing Areas • Fleet flexibility • Grid-friendly renewable power plants and controls • Forecasting • Operation strategy, policy, and power markets/mechanisms play an important role Sound policy development strikes a critical balance between the level of regulatory requirements, economic incentives and systemic cost © 2016 General Electric International, Inc All rights reserved Not for distribution without permission © 2016 General Electric Company All Rights Reserved 45 [...]... for distribution without permission 11 For grid operations, wind is “similar” to load 50 • Like load, wind can be forecast a day ahead 45 • Grid operators can plan day-ahead operations base on a load forecast and a wind generation forecast • Uncertainty in the wind forecast adds to the uncertainty in the load forecast • Adjustments are made using hourahead forecasts and real-time data 40 35 30 GW • Dispatchable... to Wind and Solar Wind Variability and Reserves •Variability depends MW level… at medium to high wind speeds, generation and variability high •However, at higher wind speeds, variability is low since generation is maxed using pitch control Wind Reserve Determination Methodology • ∆P = Difference between successive 10 min actual Wind output • Wind plant output divided into 30 MW bucket • Standard deviation... due to Wind and Solar Contingency Reserve Requirement TOTAL Reserve Requirement = Reserve requirement due to Solar + Reserve requirement due to Wind + Contingency Reserve Requirement + 30 MW 20 © 2016 General Electric International, Inc All rights reserved Not for distribution without permission Grid Operations with High Penetration of Wind and Solar Power Examples from NREL’s Western Wind and Solar... permission 13 Contingency and Operating Reserves Critical to Power System Operational Security © 2016 General Electric International, Inc All rights reserved Not for distribution without permission 14 Contingency and Operating Reserves Contingency Reserves • MWs to cover for the loss of the largest unit (185 MW Coal Unit) Operating Reserves • • MWs to cover for the variability of wind and solar Spinning Reserves... learning about reserves • Following example from an approximately 1500 MW system with a few very large wind and solar PV projects… Reserves for Wind Development of Study Cases and Data Wind Data Lowest wind tends to be late afternoon in the summer Highest wind tends to be early hours in fall and winter Actual wind power output for year 2019 averaged over each hour for each month 17 © 2016 General Electric... and Solar Integration Study © 2016 General Electric International, Inc All rights reserved Not for distribution without permission 21 Western Wind and Solar Integration Study Scenario Overview Wind and Solar Combinations (% Energy) Baseline: Existing Wind and Solar Generation 10% In-Area: 10% Wind, 1% Solar In Footprint 10% Wind, 1% Solar Out of Footprint 20% In-Area: 20% Wind, 3% Solar In Footprint... TUE JUL 11 WED JUL 12 THU JUL 13 FRI JUL 14 SAT JUL 15 MON JUL 10 SUN JUL 16 Study Area Dispatch - Week of July 10th - 20%R 70,000 60,000 TUE JUL 11 WED JUL 12 THU JUL 13 FRI JUL 14 SAT JUL 15 SUN JUL 16 Study Area Dispatch - Week of July 10th - 30%R 70,000 20% Wind Energy 60,000 50,000 40,000 40,000 MW MW 50,000 30% Wind Energy 30,000 30,000 20,000 20,000 10,000 10,000 0 0 MON JUL 10 TUE JUL 11 WED... APR 10 TUE APR 11 WED APR 12 THU APR 13 FRI APR 14 SAT APR 15 TUE APR 11 WED APR 12 THU APR 13 FRI APR 14 SAT APR 15 SUN APR 16 SUN APR 16 GT needed for big forecast error Study Area Dispatch - Week of April 10th - 20%R CC Units Not Running Study Area Dispatch - Week of April 10th - 30%R 50,000 50,000 40,000 40,000 30,000 MW MW 30,000 20,000 20,000 10,000 0 MON APR 10 10,000 TUE APR 11 WED APR 12 THU... MON APR 10 TUE APR 11 WED APR 12 THU APR 13 FRI APR 14 © 2016 General Electric International, Inc All rights reserved Not for distribution without permission SAT APR 15 SUN APR 16 28 Operation with 30% Wind, 5% Solar Requires significant changes to current operating practices used by Balancing Areas • Balancing area cooperation • Generation is committed and dispatched on an economic and regional basis... 10,000 0 MON JUL 10 TUE JUL 11 WED JUL 12 THU JUL 13 FRI JUL 14 SAT JUL 15 SUN JUL 16 © 2016 General Electric International, Inc All rights reserved Not for distribution without permission 25 Area Dispatch - Week of Footprint, July 10th - 30%R30% Wind WeekStudy of July 10th, Study 70,000 Less Combined Cycle Less GT 60,000 50,000 MW 40,000 30,000 20,000 10,000 0 MON JUL 10 TUE JUL 11 WED JUL 12 THU JUL 13 ... permission 11 For grid operations, wind is “similar” to load 50 • Like load, wind can be forecast a day ahead 45 • Grid operators can plan day-ahead operations base on a load forecast and a wind... from Western USA, New York, and California) • Share ideas on how to evaluate and quantify the impact of wind power on the overall power grid • Share lessons learned – and advice looking forward... instantaneous demand, Interchange Schedule, Operating Reserve, and reactive resource requirements • Provide its frequency bias obligations • Balance its Net Actual Interchange and Net Scheduled