Energy storage helps match wind and solar output with demand, helping electricity end users avoid peak pricing (price spikes).
Battery Energy Storage Systems are the most scalable grid-scale storage technology, experiencing rapid growth over the last several years and expected to play an ever greater role as we move towards net zero energy production. Other grid-scale storage technologies include pumped hydropower storage and thermal ice storage technologies.
Long-Duration Storage
As battery technology improves and costs decline, many observers are eyeing longer-duration storage solutions as potential sources of high value grid services like frequency regulation and capacity shifting. But cost declines alone may not be enough to motivate this next phase of development – state procurement mandates and reforms to capacity markets will play an integral role in making long-duration storage more widely applicable across a variety of settings.
Long-duration energy storage technology refers to products and methods capable of storing electricity for at least ten hours at once, such as pumped hydro storage (which pump water uphill into reservoirs when electricity prices are low, then uses that water when electricity prices increase), thermal storage technologies that use sunlight to heat or cool tanks or buildings; compressed air energy storage (CAES), which sends pressurized air into built or natural vaults like underground caverns; flow batteries which use chemicals instead of mechanical mechanisms as examples of long-duration energy storage technologies; flow batteries.
Short-Duration Storage
Effective energy storage technologies can balance supply and demand on timescales from fractions of a second to hours, helping balance supply and demand across America and reducing peak-demand power costs for American homes and businesses alike. This keeps electricity prices lower – benefiting all sources of generation including renewable sources like wind.
Battery Energy Storage Systems (ESSs) use electricity from the electric power grid to charge their batteries before discharging to produce electricity as needed. EIA reports both gross and net generation by these ESSs: gross generation refers to how much electricity was produced directly by power cells; net generation refers to how much electricity was actually produced minus how much was needed to charge its batteries.
Flywheels and compressed air storage technologies also play a part in stationary energy storage systems. Flywheels store electrical energy by splitting water molecules into hydrogen and oxygen ions which can then be stored in pressurized containers. In 2022, the United States had four such operational flywheel ESSs, each having approximately 47MW nameplate capacity with 17MWh of energy storage capability.
Fast-Response Storage
Electricity demand has become less predictable over time, due to spikes and drops caused by everything from data centers to weather events. As such, utilities have turned toward energy storage to help stabilize their grid.
Energy storage responds almost instantaneously to fluctuations in energy demand, helping ensure lights stay illuminated, refrigerators stay cold, Wi-Fi keeps working and medical devices can operate seamlessly. Independent power producers and public utilities alike are turning to battery energy storage to enhance grid resilience and stability.
Battery energy storage can help power system operators mitigate the effects of intermittent wind and solar generation by responding to transmission system operator dispatch calls for supply requests (dispatch calls). EIA publishes both gross and net generation figures for energy storage systems; gross generation refers to how much electricity they supply into the grid while net generation refers to what amount is supplied minus what was used to recharge.
Flexible Storage
Businesses using flexible energy storage solutions can leverage them to adapt quickly to changing inventory, needs or seasonal trends without incurring costly upgrades. They’re especially beneficial for companies offering seasonal products or temporary projects which might easily exceed on-site capacity limits.
Energy storage technology can be found across a wide range of settings – including transmission and distribution networks, commercial buildings and residential homes, or co-located with solar or wind power plants – in order to offset their more variable electricity output, providing more consistent production against demand. Its purpose is to balance out their electricity output while smoothing their generation more accurately in tandem with demand.
Storage systems can help decrease end-user demand charges imposed by electricity utilities by reducing high energy consumption during peak demand periods. They can also be combined with microgrids to provide resilience for communities prone to blackouts or disruption from larger electrical grids; such as homes or communities far removed from that network that can’t rely on its local system for power.