Energy storage enables grid operators to meet electricity supply and demand requirements while increasing power quality, while helping integrate renewables. Energy storage also provides consumers and businesses with lower costs overall.
ESS technologies range from battery energy storage systems, thermal energy storage units and mechanical energy storage (pumped hydro, flywheels and compressed air). Grid batteries operate effectively in various environments from freezing temperatures to desert heat.
Battery or BESS
One of the key challenges of electricity grids around the world is matching supply with demand. This can be especially difficult when transitioning to low-carbon electricity generation such as solar and wind power that only produce power when sun shines or winds blow.
BESS can provide an essential service by storing energy when it is produced and releasing it back into the grid when there is an energy deficit. They’re also essential in terms of improving grid balancing and making renewables dispatchable – meaning green energy can still be utilized when sun or wind don’t shine!
Battery storage systems rely on rechargeable batteries to store energy before converting the direct current stored within them into the alternating current used to power homes and businesses. Modern systems typically employ lithium-ion batteries, which offer longer charge retention than their lead-acid alternatives as well as higher levels of safety with detailed emergency response plans and cutting-edge battery tech that prevent thermal runaway.
Thermal storage
Energy storage systems are neutral technology and fuel, providing benefits to electricity grids regardless of generation technologies. They can optimize supply and demand, shift generation to peak demand periods, alleviate transmission congestion issues, provide grid management services and lower both cost and emissions.
Thermal energy storage typically utilizes sensible heat by changing the temperature of a medium such as water, sand or bedrock – this is the most widely available and commercially viable method. Other technologies use latent heat or chemical reactions to store and release energy; instant cold packs used by skiers contain iron powder soaked with oxygen-free salt that corrodes over time and releases heat as it decomposes.
Energy storage can enhance power quality and reliability for critical infrastructure such as data centers and advanced manufacturing. Furthermore, it can speed renewable integration by smoothing variable output from solar and wind farms while offering behind-the-meter resilience via black start capabilities and emergency backup power in disaster-prone regions.
Thermo-chemical storage
Thermochemical energy storage (TCES) relies on chemical reactions to store and release heat. This provides high energy density with long term storage capability that can easily integrate with renewables or industrial processes. At SRNL we are currently developing advanced reactant materials and control systems for TCES technologies that could enable commercial adoption.
In the charging phase, heat is absorbed by TCES material and converted to energy through endothermic chemical reactions that produce end-products; these end-products can then be separated, stored separately and later combined again when necessary to release energy for use when required.
TCES can provide an attractive solution for off-peak power generation or industrial waste heat reduction at low temperature levels, such as where energy storage is required at lower temperature levels. TCES systems can also serve as backup power in solar power plants when sun or wind resources are in short supply; providing energy back-up on days when these resources cannot provide power directly. Unfortunately, however, TCES systems require advanced reactants, customized reactor designs, and complex control systems in order to work successfully.
Gas storage
Gas storage facilities serve a number of functions. First, they ensure commodity liquidity at market centers by providing additional supplies when demand spikes occur; they also help reduce price volatility and uncertainty; finally they satisfy regulatory requirements by covering winter peak demands when traditional supplies fall short.
Energy storage bolsters a green, resilient grid by increasing efficiency, flexibility and large-scale electrification. It supports both traditional and renewable generation sources while optimizing supply/demand ratios to minimize consumer costs, helping integrate new renewable electricity sources and providing backup power during outages for homes, businesses and critical infrastructure.
Energy storage systems (ESSs) vary in their length of service depending on their type and project; pump hydro, compressed-air storage systems provide diurnal energy storage while battery systems provide short duration energy delivery. By including various energy storage technologies into state and regional energy plans, faster project approval processes and improved grid integration may result.