Energy storage refers to technologies that capture electricity when it is available and release it later when needed. Storage plays a critical role in modern grids by:
- Balancing supply and demand
- Integrating intermittent renewables (wind, solar)
- Providing flexibility for markets and system operators
- Supporting reliability and grid stability
Types of Energy Storage
1. Battery Storage (Battery Farms)
- Large-scale installations of lithium-ion or other battery technologies
- Can store excess electricity from renewables or low-demand periods
- Rapid response makes them suitable for:
- Frequency regulation
- Peak shaving
- Grid support during outages
2. Distributed Storage (EVs, Home Batteries)
- Electric vehicles (EVs) or residential battery systems act as small-scale, distributed storage units
- When aggregated, these resources can provide virtual power plant (VPP) capabilities
- Enables:
- Demand shifting
- Local network support
- Revenue opportunities via participation in Flexibility Markets
3. Other Storage Technologies
- Pumped hydro: Stores energy as potential energy by pumping water uphill, released later through turbines
- Compressed air energy storage (CAES): Compresses air to store energy, releases it later to generate electricity
- Thermal storage: Stores heat or cold to offset electricity use (e.g., heat batteries, ice storage)
Market and Operational Role
- Stored energy can be traded on electricity markets just like generation.
- Example: Buy electricity at low price, release it during peak price
- Provides Ancillary Services such as frequency response and voltage support
- Supports renewable integration by smoothing out variable generation
Interaction with Demand Response
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Storage and DR are complementary:
- DR shifts demand to reduce peaks
- Storage shifts supply to meet peaks
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EVs and other distributed storage can act both as flexible demand and dispatchable supply
Key Takeaways
- Energy storage increases grid flexibility and reliability
- Can be centralized (battery farms, pumped hydro) or distributed (EVs, home batteries)
- Enables trading, revenue generation, and renewable integration
- Works together with DR to balance supply and demand dynamically