Energy storage enables renewable energy sources like solar and wind power to be available when needed, not just when sunlight or winds blow. Similar to your phone or electric car battery, commercial and utility-scale battery energy storage systems (ESSs) are charged using electricity from the grid.
ESSs help lower end-user demand charges while supporting a smarter, more resilient electricity grid as clean energy sources expand.
Battery Storage
At present, most commercially deployed battery energy storage systems (ESSs) consist of lithium-ion batteries – the kind you might find powering your phone or electric car. These technologies are ideal for balancing intermittent renewable sources like solar and wind to meet electricity demand while providing grid services such as ancillary services and operating reserves as well as providing other utility benefits like transmission/distribution investment deferral/congestion relief/local resource adequacy.
ESSs have also proven useful in lowering end-user electricity demand and associated charges through utility demand-side management programs, and in increasing grid resilience by discharging quickly to prevent outages. Furthermore, these systems can also be integrated into microgrids to provide these same services to communities far removed from the main grid; such as islands or remote regions.
Due to their costly construction and maintenance requirements, most people don’t want power lines near their homes; intelligently placed ESSs can add capacity and resilience on an existing electric grid without adding new lines – hence our term “Non-Wires Alternative”.
Hydrogen Storage
Hydrogen storage offers long-duration energy storage with the potential to supply hours of power. Pumped hydrogen and compressed-air systems support diurnal storage at various operational costs depending on system size and system type; hybrid battery, fuel cell and metal hydride setups may also be utilized for longer duration energy storage needs. Hydrogen can be stored as gas in high-pressure tanks (350-700 bar) or created via electrolyzing water to produce hydrogen gas that can then be converted back into electricity through fuel cells.
Hydrogen energy storage and transport have become essential elements of solar- and wind-powered microgrids, providing rapid response to changes in electricity demand while supporting grid stability with functions such as voltage and frequency regulation. Furthermore, hydrogen helps extend renewables’ benefits into remote and off-grid locations through innovations like leak-reducing pipeline materials; modular systems shipped in shipping containers for quick installation; and stations adapting with existing natural gas pipelines using blending technology.
Fuel Cell Storage
Fuel cells offer superior energy efficiency compared to batteries for powering portable electronics and some electric vehicles, and can operate on multiple scales: from small portable systems that supply off-grid electricity for cellphone towers through forklifts in warehouses to megawatt-scale power plants that deliver clean electricity sustainably.
Hydrogen fuel cells generate electrical power by converting chemical energy directly into heat and electricity without emitting greenhouse gases or other pollutants, offering quiet, scalable solutions without producing noise and fumes like generators do – they replace generators which emit noise as well as toxic fumes – and can be powered either by natural gas, alternative fuels/biofuels, hydrogen or any combination thereof depending on the system requirements.
Plug’s zero-emission fuel cell systems have been utilized as backup power generation for telecom networks, materials handling equipment in warehouses and major wineries, transportation to reduce “middle mile” emissions (57% of greenhouse gas pollution within the U.S.), as well as to reduce “middle mile” emissions (57% of total U.S. greenhouse gas pollution). Unlike batteries, fuel cells don’t degrade over time or lose performance, and can easily be refueled via hydrogen pipelines similar to filling a gas tank.
Thermal Storage
Thermal energy storage allows individuals or communities to store heat or cold at one time for use at another. This could involve anything from creating ice cubes in your refrigerator at night and using them for cooling in the day to more complex ground-based thermal batteries that store seasonal heat underground by injecting and expel it over an annual cycle.
Thermal storage technology can be applied in various settings ranging from local markets (like supermarkets) to utility scale, providing grid services such as frequency regulation. Furthermore, its deployment helps accelerate clean energy integration by decreasing peaker plant requirement.
Back-up power and smart electricity management systems that optimize renewable energy usage for cost and efficiency can also provide back-up power, as well as increasing deployment of fluctuating renewable sources thereby increasing system reliability.