Energy storage provides an essential bridge towards a world dominated by renewable electricity sources. It facilitates electric vehicle usage as well as off-grid solar home operations efficiently.
IRENA’s Energy Storage Cost-of-Service Tool 2.0 offers an accessible and quick way of assessing the cost-effectiveness of various Energy Storage technologies. Energy storage technologies may include Electrical Energy Storage or Thermal Energy Storage systems.
Battery Storage
Battery Energy Storage Systems (ESSs) are essential tools in the transition towards renewables, helping to balance out fluctuations between electricity generation and demand. Delivering their full rated power for durations up to 4 hours at any one time, these ESS are often co-located with photovoltaic or wind projects for optimal use.
ESS systems provide numerous advantages that increase power grid efficiency while simultaneously lowering electricity costs for consumers. By helping manage energy supply and demand spikes and valleys more effectively, they replace many fossil-fuel fired plants which normally operate during these times, ultimately leading to reduced bills and saving consumers money in energy costs.
Dependent upon their technology, these systems may also provide ancillary services to ensure a reliable and cost-effective electricity grid. Furthermore, these energy flexibility services such as ancillary services programs, grid support operations, local resource adequacy capabilities may open revenue opportunities as well as reduce or avoid costly upgrades to poles, wires and substations.
Hydroelectric Storage
Pumped hydropower storage is currently the dominant form of grid-scale energy storage. Like batteries, pumped hydro relies on using a lower reservoir at one elevation to pump water up through an elevated power station and generate electricity during times of high demand.
Pumped storage power plants offer several distinct advantages over batteries; unlike batteries, they can recycle water multiple times over an extended period, providing consistent output throughout. Furthermore, pumped storage plants offer other ancillary services like network frequency control and reserve services.
Pumped hydro can respond much more rapidly than other forms of storage, making it ideal for load balancing at large nuclear or thermal generating stations, so as not to overproduce during peak hours.
Pumped hydro storage (PSH), first employed nearly 100 years ago, remains one of the primary forms of storage on today’s grid with approximately 23 gigawatts (GW) currently operating across 43 PSH sites in the US alone.
Flywheel Storage
Flywheel systems utilize surplus electricity to accelerate their rotor to high speeds, then retain this rotational energy much like how figure skaters speed up their spin by pulling in their arms. When necessary, this kinetic energy can then be turned back into electricity.
Temporal’s flywheel systems are frequently employed as uninterruptible power supplies (UPS). One of their initial clients was a hospital in Mississauga which uses their UPS to protect radiology suites against voltage sags and outages.
Large flywheels can help regulate power coming onto electricity grids from intermittent generators such as wind turbines. By storing energy in giant, solid steel flywheels weighing 4,000 kilograms until needed, large flywheels ensure efficient and reliable grid operations; additionally, they may also be used to incorporate renewables into micro grids in remote islands or regions like Alaska or Canada.
Thermal Storage
Energy storage enables us to temporarily reserve heat or cold energy for use at a later date. Examples include rechargeable batteries that store chemical energy to power mobile phones; pumped-storage hydroelectric dams; thermal storage such as molten salts that efficiently store and release large amounts of heat to generate electricity; and ice thermal storage systems (like those utilized by Duquesne University) that reduce daytime air conditioning demands by temporarily reserving it in reserve.
Energy storage provides power grids with the means of mitigating fluctuations between supply and demand, frequency regulation and voltage control as well as frequency response services. Energy storage becomes even more essential as we move further from the electrical grid, such as rural communities, islands or microgrids; the updated spreadsheet-based Energy Storage Cost of Service Tool can assist in analysing different ESS configurations while providing an understanding of their techno-economic characteristics in order to find cost-effective options.