2015年-世界发展银行全球_Bringing_Variable_Renewable_Energy_Up_to_Scale___Options_for_Grid_Integration_Using_Natural_Gas_and_Energy_Storage_96页_1mb

Summary of Technical Report 006/15: Bringing Variable Renewable Energy (VRE) Up to Scale

Core Content

This technical report explores the challenges and solutions for integrating high levels of Variable Renewable Energy (VRE), specifically wind and solar, into power grids. It emphasizes the importance of flexibility in managing the variability and uncertainty of VRE and presents two key options for achieving this flexibility: natural gas-fired generation and energy storage.

Main Views and Key Information

1. Introduction to VRE Integration

• Global Context: By the end of 2013, 144 countries had set renewable energy expansion plans, with solar and wind being the most variable renewable sources.
• Drivers for Renewable Development: Countries pursue renewable energy for reasons such as increased energy security, environmental benefits, energy access, industrialization, job creation, and affordability.
• VRE Characteristics: Solar and wind have high variability and limited predictability, which pose challenges for grid operators.

2. Challenges of VRE Integration

• Power System Operator Responsibilities: Operators must balance supply and demand, manage fluctuations, and maintain grid stability.
• Operational and Planning Challenges:
  • At low VRE shares (below 5-10%), variability is manageable with operational adjustments.
  • As VRE shares increase, additional measures are required to ensure grid performance.
• Key Measures for VRE Integration:
  • Supply-side flexibility (e.g., flexible generation technologies).
  • Demand-side flexibility (e.g., demand response).
  • Storage technologies to manage imbalances.

3. Natural Gas as a Flexibility Option

• Flexibility Provided by NG:
  • NG-fired technologies have faster start-up and ramp-up rates compared to coal or nuclear.
  • CCGT (Combined Cycle Gas Turbine) plants are the most common for base-load and non-peak operations.
  • New "fast-acting" CCGTs can reach full load in less than 40 minutes.
• Limitations:
  • NG has limitations in start-up times, ramp rates, and turn-down ratios.
  • Part-load operation increases emissions and maintenance costs.
  • NG generators have a reduced operating life when used for frequent adjustments.

4. Energy Storage as a Flexibility Option

• Storage Technologies:
  • Preferred for time-shifting energy and balancing VRE output.
  • Include pumped hydro, compressed air energy storage (CAES), multiple battery technologies, and thermal storage.
• Rapid-Response Technologies:
  • Flywheels, high-power lithium-ion batteries, and super capacitors are suitable for load following and regulation.
• Limitations:
  • Higher costs and limited operational experience.
  • Uncertainty in long-term performance and maintenance.
• Prospects:
  • Projected cost reductions and growing commercial track record may make storage viable for long-term planning.

5. Planning, Policy, and Regulation Considerations

• Financial Viability of Gas-Fired Plants:
  • High VRE shares reduce utilization of conventional plants, leading to potential write-downs and decommissioning.
  • Flexibility is crucial for maintaining system adequacy and stability.
• Implications for NG Demand:
  • Increased VRE shares may require more flexible gas supply.
  • Coordination between electricity and gas sectors is necessary for supply security.
• Long-Term Planning:
  • Must account for short-term imbalances.
  • Use of advanced modeling can help evaluate VRE impacts and optimize integration strategies.
  • A combination of measures (flexible generation, demand response, storage) is needed for effective VRE integration.

6. Conclusions and Recommendations

• Policy and Planning Focus:
  • Interventions should aim to minimize overall system costs while meeting performance targets.
  • Flexibility requirements should be technology-agnostic unless specific reasons exist for using a particular technology.
• Recommendations:
  • Consider the full range of flexibility options.
  • Implement a comprehensive planning process that includes advanced modeling.
  • Define remuneration mechanisms for flexible capacity.
  • Coordinate planning and infrastructure investments between electricity and gas sectors.

Key Figures and Tables

• Figure 1.1: Countries with Renewable Energy Targets.
• Figure 2.1–2.10: Illustrate VRE variability, integration challenges, and measures.
• Figure 3.1–3.3: Compare NG technologies' performance and start-up times.
• Figure 4.1–4.7: Detail storage technologies, applications, and costs.
• Table 4.1: Energy storage performance metrics.

Acronyms and Abbreviations

• AGC: Automatic Generation Control
• CCGT: Combined Cycle Gas Turbine
• CAES: Compressed Air Energy Storage
• DES: Distributed Energy Storage
• DR: Demand Response
• DSM: Demand-Side Management
• LCOE: Levelized Cost of Electricity
• NG: Natural Gas
• OCGT: Open Cycle Gas Turbine
• PV: Photovoltaic
• RE: Renewable Energy
• TES: Thermal Energy Storage
• VRE: Variable Renewable Energy

Conclusion

The report concludes that while VRE presents significant challenges to grid integration, the use of natural gas and energy storage can help manage variability and uncertainty. A comprehensive and flexible approach, supported by appropriate policy and planning, is essential to achieve cost-effective and reliable integration of VRE into power systems.