Fact Sheet: Energy Storage (2019)

By District Energy posted 03-07-2019 00:00

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Alexandra Zablocki, Environmental and Energy Study Institute

Summary

Due to growing concerns about the environmental impacts of fossil fuels and the capacity and resilience of energy grids around the world, engineers and policymakers are increasingly turning their attention to energy storage solutions. Indeed, energy storage can help address the intermittency of solar and wind power; it can also, in many cases, respond rapidly to large fluctuations in demand, making the grid more responsive and reducing the need to build backup power plants. The effectiveness of an energy storage facility is determined by how quickly it can react to changes in demand, the rate of energy lost in the storage process, its overall energy storage capacity, and how quickly it can be recharged.

Energy storage is not new. Batteries have been used since the early 1800s, and pumped-storage hydropower has been operating in the United States since the 1920s. But the demand for a more dynamic and cleaner grid has led to a significant increase in the construction of new energy storage projects, and to the development of new or better energy storage solutions.

Fossil fuels are the most used form of energy, partly due to their transportability and the practicality of their stored form, which allows generators considerable control over the rate of energy supplied. In contrast, the energy generated by solar and wind is intermittent and reliant on the weather and season. As renewables have become increasingly prominent on the electrical grid, there has been a growing interest in systems that store clean energy

Energy storage can also contribute to meeting electricity demand during peak times, such as on hot summer days when air conditioners are blasting or at nightfall when households turn on their lights and electronics. Electricity becomes more expensive during peak times as power plants have to ramp up production in order to accommodate the increased energy usage. Energy storage allows greater grid flexibility as distributors can buy electricity during off-peak times when energy is cheap and sell it to the grid when it is in greater demand.