Energy storage systems balance supply and demand in the grid primarily by storing excess electricity when supply exceeds demand and releasing it when demand is higher than supply. This time-shifting capability helps to smooth out fluctuations caused by variable renewable energy sources like solar and wind power, which are intermittent by nature. For example, energy can be stored during times of high solar generation in the day and then supplied back to the grid at night or during disruptions in generation, maintaining a reliable power supply.
More specifically, these systems contribute to grid stability by providing services such as frequency regulation. The grid frequency must be kept within tight limits (around 50 or 60 Hertz) for stable operation; deviations can lead to blackouts or equipment damage. Battery energy storage systems (BESS), in particular, can respond very rapidly to frequency changes by charging when there is excess energy and discharging during shortages. This fast response supports real-time balancing of supply and demand, ensuring the grid remains stable despite increasing shares of renewables.
Types of grid energy storage vary based on the duration of storage needed. Lithium-ion batteries are well-suited for shorter durations (up to 8 hours), while other technologies like flow batteries, compressed air storage, and green hydrogen address medium to long-duration storage requirements. Long-duration storage becomes more critical as renewable energy penetration rises above 80-90%, helping maintain balance over longer periods when renewable output may be low.
In addition to storing energy, other complementary methods to balance the grid include dispatchable power plants that can quickly ramp output, demand response programs that shift load to different times, and inter-regional power exchanges.
In summary, energy storage systems enhance grid flexibility and reliability by:
- Capturing excess electricity during periods of oversupply,
- Releasing stored energy during deficits,
- Providing fast frequency regulation,
- Supporting integration of variable renewables,
- Enabling longer-duration balancing as renewables increase.
This makes storage a key technology for balancing supply and demand on modern power grids transitioning to cleaner energy sources.
Original article by NenPower, If reposted, please credit the source: https://nenpower.com/blog/how-do-energy-storage-systems-balance-supply-and-demand-in-the-grid/
