FLEXIBILITY: KEY TO UNLOCKING POWER SYSTEM TRANSFORMATION

Transcription

1 FLEXIBILITY: KEY TO UNLOCKING POWER SYSTEM TRANSFORMATION Prospects for Solar PV and Storage Technologies in the Future Energy Landscape Singapore

2 OUTLINE About 21CPP Power System Transformation: US Snapshot Background on RE Integration and Flexibility 21CPP-IEA Power Plant Flexibility Study Summary

3 21CPP OBJECTIVES: POWER SYSTEM TRANSFORMATION

4 21CPP WORK STREAMS Annual Program of Work Includes: Thought-Leadership studies that focus on generic power system transformation topics across the world In-country technical assistance, often as part of a larger development assistance effort, focused on policy, regulatory, and technological progress; grid integration studies often highlight this work. Information exchange, capacity building, fellowship programs, and other exercises to share lessons-learned and knowledge transfer.

5 U.S. POWER GENERATION DYNAMICS 2000 Annual U.S. Net Generation by Fuel Coal 1400 Terawatt-hours Petrol Geothermal Biopower Hydro Natural Gas Nuclear Wind Solar

6 U.S. POWER GENERATION DYNAMICS 2000 Annual U.S. Net Generation by Fuel 1800 Coal Terawatt-hours Nuclear Hydro Natural Gas Non-Hydro RE Petroleum

7 U.S. POWER GENERATION DYNAMICS 2000 Annual U.S. Net Generation by Fuel Coal Terawatt-hours Nuclear Natural Gas All RE Petroleum

8 U.S. POWER GENERATION DYNAMICS 2000 Annual U.S. Net Generation by Fuel Terawatt-hours Coal Zero Carbon (burner-tip) Natural Gas Petroleum

9 BACKGROUND ON RE INTEGRATION AND FLEXIBILITY Source: California ISO

10 GRID OPERATIONS: A MATTER OF BALANCE Supply Supply Components Demand Components Storage Renewable Generators Conventional Generators Storage Electric Vehicles Building End Uses Demand Supply and demand are both variable. The power system keeps these in balance at all times.

11 WIND AND SOLAR ADD VARIABILITY TO THE SUPPLY SIDE Source: NREL Report No. FS-6A

12 ACCESSING FLEXIBILITY IS A KEY OBJECTIVE OF RE INTEGRATION Physical power system: generators, transmission, storage, interconnection Institutional system: operations (e.g., scheduling, dispatch, forecasting), market rules, collaboration with neighbors Focus of most grid integration efforts Physical system Market and institutional filter Power system operation, reliability, cost Power system operation (and grid integration) relies on both

13 FREQUENTLY USED OPTIONS TO INCREASE FLEXIBILITY Source: Cochran et al. (2014). Flexibility in 21 st Century Power Systems.

14 FREQUENTLY USED OPTIONS TO INCREASE FLEXIBILITY

15 21CPP-IEA POWER PLANT FLEXIBILITY STUDY Released at CEM 9 (May 2018) in Copenhagen

16 ADVANCED POWER PLANT FLEXIBILITY CAMPAIGN Campaign Co-leads Non-government partners Participating CEM Members Now 14 partner countries and 14 industry and NGO partners membership has increased throughout the duration of the campaign

17 RELEVANT DIMENSIONS FOR UNLOCKING SYSTEM FLEXIBILITY Technical, economic and institutional policy layers mutually influence each other and have to be addressed in consistent way to enhance power system flexibility.

18 FLEXIBILITY NEEDED ACROSS A WIDE- RANGE OF TIME SCALES Timescale Issue Short-term flexibility Subseconds to seconds Address system stability, i.e. withstanding large disturbances such as loosing a large power plant Seconds to minutes Address fluctuations in the balance of demand and supply, such as random fluctuations in power demand Medium-term flexibility Long-term flexibility Minutes to hours Hours to days Days to months Months to years Manage ramps in the balance of supply and demand, e.g. increasing electricity demand following sunrise or rising net load at sunset. Decide how many thermal plants should remain connected to and running on the system. Managing scheduled maintenance of power plants and larger periods of surplus or deficit of energy, e.g., hydropower availability during wet/dry season Balance seasonal and inter-annual availability of variable generation (often influenced by weather) and electricity demand System flexibility addresses a set of issues, spanning timescales from subseconds to years.

19 POLICY GUIDELINES FOR FLEXIBILITY DEPLOYMENT Power plant flexibility can be rolled out successfully by following a set of best practice policy guidelines.

20 CONSIDERATION #1 ASSESS Building up a flexibility inventory can allow policy makers to see what options are available today and how to plan for future flexibility requirements

21 CONSIDERATION #2 ENGAGE Domestic and international stakeholder engagement can help build momentum for embedding flexibility in modern power systems

22 CONSIDERATION #3 ENHANCE Enhancing system-wide flexibility requires coordinating technical options from operational changes to demand-side measures

23 CONSIDERATION #4 UNLOCK Review must-run requirements for power plants Oversee the review of electricity and fuel contracts to enhance flexibility through contract flexibility Allow VRE participation in reserve provision Generation/Load (MW) Dec 00:00 31 Dec 06:00 31 Dec 12:00 Core RE2 31 Dec 18: Dec 00:00 31 Dec 06:00 Plant and contract flex RE2 31 Dec 12:00 31 Dec 18:00 NUCLEAR COAL BIOMASS_WASTE OtherGas CCGT HYDRO SOLAR WIND OCGT DIESEL VRE curtailment Load Net Load Unlocking flexibility from existing assets can be a cost-effective approach but should be informed by cost-benefit analyses

24 CONSIDERATION #5 -- INCENTIVIZE In liberalized markets Improve wholesale market design Implement market instruments for all relevant system services Introduce capacity mechanisms that value flexibility In regulated markets Allow cost recovery for retrofit investments Provide incentives that allow for resilient, high-flexibility components in new power plants Introduce fair remuneration that accounts for the system value of flexibility

25 CONSIDERATION #6 ROADMAP Encourage the inclusion of flexibility assessments in planned system adequacy assessments Request state-of-the-art decision support tools for long-term planning purposes Encourage the integration of generation and transmission investment planning Assess costs and benefit of demand-side resources and electricity storage options Long-term system transformation is an iterative process that requires regular evaluation and update of system planning

26 MOORFLEX: FLEXIBLE COAL AND CO- GENERATION Measures Results Co-generation plant located in Hamburg with 827MWe capacity. Plant was unable to obtain sufficient revenue from base-load operation under current market conditions. Reduction of minimum stable output levels from 35% to 26% Optimization of control loops and operation modes Retrofitting with flue gas dampers to regulate cooling Reduction of minimum stable output level lead to reduced number of start-ups and shutdowns associated with increased costs Faster ramping rates: able to ramp at 48MW/min and up to 90MW/min under special conditions Improved start-up: Warm-cold 20% faster Warm 42%-50% faster Hot 40 46% faster Source: Case-study provided by MHPS, March Vattenfall (2016) Increasing power plant flexibility can enable existing assets to remain profitable despite changing market conditions.

27 LA CASELLA: CCGT REFURBISHMENT FOR INCREASED FLEXIBILITY Built in the 1970s as an oil-fired plant for baseload operation. Converted to a CCGT with four 370MW units between 2000 and First intervention in 2008, second in 2014 to adapt to new market requirements: competition and reserve provision. 1 st set of measures Results Exploration of plant s real limits and constraints Equipment modernization and partial automation Update to operational procedures 2 nd set of measures Optimisation of combustion behaviour at low loads Study of component limits under increased stress conditions, particularly HRSG unit. Measurement and redesign of turbine to reduce rotor stress Start-up time improvement: Warm 50% faster Cold 20% faster Reduced minimum stable level from 230 MW to 170 MW and faster ramping Ability to provide reserve and meet emissions requirements Reduced damage to equipment in the face of faster ramps Data availability and experiences have been deployed across ENEL s fleet Source: ENEL Improving plant performance is an iterative process that extend the plant s lifetime, while ensuring that changing market requirements and regulations are upheld.

28 KYUSHU: FLEET COORDINATION FOR INCREASED FLEXIBILITY With 6 GW installed PV capacity, 16 GW peak load and 8 GW minimum daytime load, Japan s southern-most main island, Kyushu, has the highest VRE penetration in Japan. 6 dispatch rules developed by the Japanese Organization for Cross-regional Coordination of Transmission Operators: Avoid generation from reservoirs and PSH during daytime. Prioritise electricity surplus absorption by PSH. Reduce thermal plant output to minimum stable levels. Export surplus electricity through cross-regional interconnectors. Reduce biomass power plant output. Curtail solar PV and wind as a last resort. Source: Kyushu EPCO Avoiding thermal generation shutdown is crucial as their start-up times range between 2 and 8 hours At sun-down solar PV output decreases at ~1.3GW/hour High solar PV penetration highlights the importance of improving forecasting Introducing protocols for coordinating power plant response to manage VRE variability can be useful in maintaining system stability at high VRE shares.

29 MAIN FINDINGS Across power systems with economic dispatch, increasing VRE penetration is redefining the way conventional assets operate The case-studies show that there is a range of technically and economically feasible solutions to improve plant flexibility and reduce VRE curtailment Regulation and market rules are crucial in unlocking flexibility across all technologies Generation technologies vary in their ability to provide flexibility across time-frames Main technical parameters Minimum stable output Reduces plant shut-down and costs Ramp rate and start-up Improve response time to VRE variability Minimum up and down times Improved scheduling flexibility

30 FLEXIBLE THERMAL GENERATION BUSINESS AS USUAL ALREADY TODAY Conventional electricity generation in Germany in November Other Pumped storage hydro 50 Natural Gas GW Hard coal Lignite November 2017 Nuclear Source: Agora (2018b), Die Energiewende im Stromsektor: Stand der Dinge 2017 The significant share of relatively inflexible generation, coupled with high VRE variability, make flexibility a priority for the operation of Germany s power system

31 CAMPAIGN CONTINUATION: NEW FOCUS ON SYSTEM FLEXIBILITY Continuation of the APPF campaign with a wider scope on power system flexibility 3 deep-dive workshops

32 KEY MESSAGES Power plants are one option to provide system flexibility, but many other options are available in modern power systems. Experience and examples highlighted in the report establish that many, if not all, power plant technologies can operate flexibly and across multiple timescales of power system operation. The role of existing thermal power plants is transitioning in many modern power systems toward more flexible modes of operation and, at times, reduced operating hours. Significant system flexibility lies latent in many power plants; global experience suggests a range of known strategies are available to unlock that flexibility, many of which are non-technical. Generators that were initially designed and operated as inflexible have been successfully engineered into highly flexible assets Incorporating regular flexibility assessments into planning and strategy dialogues is key. Established decision support tools can be used to assess flexibility requirements, understand the value of proposed changes, and plan for the future.

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34 TEN STEPS FOR FLEXIBILITY AT THE POWER PLANT LEVEL 1. Raise the awareness for flexibility: Provide background information about the need for flexibility, explain the necessity and impact on the O&M of the plant, and initiate training programs. 2. Check the status of the plant and identify bottlenecks and limitations with respect to flexible operation: Consult with OEMs to assess the influences of low load operation and temperature and pressure gradients on main components and equipment. Ensure smooth operation of all control loops. 3. Plan and execute test runs to evaluate the plant flexibility potential. Create transparency about the plant performance with respect to minimal load, start-up and cycling behavior in the current setup. Identify constraints and process limitations as well as improvement potential. 4. Optimize the information and communication system: This is the most cost-effective way to enhance the flexibility of the plant. A certain level of automation is a prerequisite for tapping this potential. 5. Implement mitigation measures to manage the consequences of flexible / cycling operation. This includes a reassessment of all O&M procedures. The use of appropriate condition monitoring systems is essential. 6. Optimize combustion: Stable combustion is the key aspect to ensure minimum load operation. 7. Optimize start-up procedures: Check start-up related temperature measurements and consider replacement; automate start-up procedures. 8. Improve the plant efficiency at part load and the dynamic behavior of the plant: Use the potential of the water-steam cycle and enhance the performance of important equipment and components, e.g. fans or feed water pumps. 9. Improve the fuel quality: The better the fuel quality the better the combustion process. 10. Consider storage options to enhance the overall flexibility performance of the plant. This refers to battery or thermal storage systems.