202101公用事业规模储能部署的四个阶段——美国电力系统中储能作用不断扩大的框架（英）-56页_3mb

Storage Futures Study Summary

Core Content

The Storage Futures Study (SFS) is a multiyear research project by the National Renewable Energy Laboratory (NREL) that explores the role and impact of energy storage in the U.S. power sector. The study presents a conceptual framework based on four phases of storage deployment, which helps utilities, regulators, and developers understand the evolving role of storage in the power system and the need for careful cost analysis to ensure optimal deployment.

Main Points

• Current Storage Landscape: The U.S. electricity system currently has about 24 GW of stationary energy storage, with most being pumped storage hydropower (PSH). PSH was primarily built before 1990 to provide peaking capacity and energy time-shifting for large, less flexible capacity.

• Phase Framework: The four phases are defined based on storage duration, ranging from shorter to longer durations, and link storage duration to specific grid services. The framework helps to predict future storage deployment and its alignment with different services.

• Phase 1 (Short-Duration Storage for Operating Reserves):

  • Duration: <1 hour
  • Primary Services: Operating reserves (including regulating, spinning, and frequency responsive reserves)
  • Deployment Potential: <30 GW
  • Key Insight: Short-duration storage is cost-effective for meeting operating reserve requirements, especially in restructured electricity markets.

• Phase 2 (Battery Peaking Power Plants):

  • Duration: 2–6 hours
  • Primary Services: Peaking capacity
  • Deployment Potential: 30–100 GW, strongly linked to PV deployment
  • Key Insight: Lithium-ion batteries are becoming cost-competitive for peaking capacity. The value of storage increases with PV deployment, and vice versa, creating a positive feedback loop.

• Phase 3 (Low-Cost Diurnal Storage):

  • Duration: 4–12 hours
  • Primary Services: Diurnal capacity and energy time-shifting
  • Deployment Potential: 100+ GW
  • Key Insight: This phase is characterized by lower costs and improved technology, enabling storage to provide diurnal services. It may include new technologies like next-generation compressed air and thermal storage. Hybrid deployments and shared capital and operating expenses are also likely.

• Phase 4 (Multiday to Seasonal Storage):

  • Duration: >12 hours (days to months)
  • Primary Services: Seasonal energy shifting and support for high RE penetration
  • Deployment Potential: Up to 250 GW or more
  • Key Insight: This phase is the most uncertain, involving long-duration storage technologies such as liquid and gas fuels. These technologies enable seasonal storage and can be used for non-electric applications, making them harder to compare with other storage technologies.

Key Information

• Economic and Technological Drivers: Declining costs of energy storage and the increasing deployment of variable renewable energy (VRE), particularly solar photovoltaics (PV), are key drivers of storage deployment.

• Value Proposition: The value of storage services does not always increase with duration. Some services may have no incremental value beyond a certain point, or the value may increase at a diminishing rate, leading to a decline in economic performance for longer durations.

• Market Conditions: The introduction of restructured electricity markets and new technologies has led to a shift in storage deployment from longer-duration PSH to shorter-duration storage since 2011.

• Future Implications: The framework suggests that future storage deployment will be progressive, with durations increasing as market opportunities for shorter durations are saturated and as VRE penetration increases.

Key Phases and Their Characteristics

Conclusion

The SFS provides a conceptual framework for understanding the evolving role of energy storage in the U.S. power system. It highlights the importance of storage duration in determining the value and economic performance of different technologies and services. The study also emphasizes the need for careful analysis to ensure cost-optimal deployment and the integration of storage with renewable energy and other flexibility resources.

The framework is intended to guide stakeholders in evaluating alternative pathways for storage and other system flexibility resources, especially as the grid evolves and the role of storage as a capacity resource becomes more significant. The study supports the U.S. Department of Energy's Energy Storage Grand Challenge, which aims to accelerate the development and commercialization of next-generation storage technologies.