How is Renewable Energy Stored?

As we continually rely on clean and renewable energy sources, such as hydro, thermal, wind and solar, new challenges are presented with the impact their intermittent flow has on the grid. Storage of energy to reliably cover the times the sun isn’t shining and the wind isn’t blowing requires a realistic solution.

The electricity grid requires supply and demand to be equal and constant adjustments to the supply are needed to mirror anticipated and unexpected changes in demand. These changes in demand consist of conditions like our typical daily routines, storms, equipment overloads and increased usage from sudden extreme temperature change.

Energy storage is an imperative piece of the delicate balancing act required to maintain the grid. Now, more than ever, the quest to create a more flexible and reliable grid is a challenge.

So How is Energy Stored?

• Batteries – Though batteries have been around for a quite some time, their technology has recently advanced due to the increasing use of electric vehicles. There are many types of batteries that have large-scale storage abilities and are excellent for storage because they can be located anywhere. Batteries increase the stability of the grid because they can be placed near consumers to provide power or near facilities, such as wind farms, for storage.
• Compressed Air Energy Storage – This method improves upon the efficient conventional gas turbines by compressing air during low demand times and storing it in underground caverns. When there is extra demand on the grid, air is pulled from the caverns and fired with natural gas in a combustion turbine to generate electricity. 
• Flywheels – A flywheel is a cylinder-shaped device that contains a large rotor inside a vacuum. It spins at a very high speed, pulling electricity from the grid and storing it as rotational energy. It releases energy back to the grid by slowing the rotor and running on inertial energy.
• Pumped Hydroelectric Storage– One of the oldest forms of energy storage is the pumping of water into higher elevation reserves or behind hydroelectric dams during low usage. Water then flows into the turbines, during periods of high demand, adding more capacity to the grid when needed.
• Thermal Storage of the Sun’s Heat – Uses power from the sun by capturing the heat and storing the energy in water, molten salts or other liquids. This can later be used to generate electricity, which enables the use of solar energy even when the sun isn’t shining.
• Thermal Storage by Freezing Water – Another thermal storage technology includes freezing water at night when electricity usage is low and using the ice during the day to condense air conditioning system refrigerant. The electricity consumption is shifted from the daytime when the grid demand is highest to a time when there’s less demand and electricity costs are lower.

What are the Benefits of Energy Storage?

Stored energy’s largest benefit is that it’s discharged to the grid rapidly as opposed to energy derived from fossil fuels, which takes significantly more time. Quick responses create more stability for the grid during times of unexpected increase in demand.

Storage is also crucial the farther away a home or business is from the grid. There is a higher probability of disruption in electricity flow for those in rural areas versus in metropolitan areas, which means storage facilities are necessary to ensure power stability for outlying areas.

Now What?

As use of renewable energy continues to expand, there are several ways to take control of your own energy spend. Do-it-yourself energy audits are a good start. Updating old appliances and machinery, as well as installing smart thermostats to control unnecessary use of temperature control when you’re not at your home or business can help. 

Check out AEP Energy’s renewable energy supply price plan for your home or business! This plan allows you to match 100% of your electricity usage with Renewable Energy Certificates (RECs), which supports renewable energy resources.

Learn more about AEP Energy’s renewable energy supply price plan by visiting our website.

Sources:
https://www.energy.gov/oe/activities/technology-development/energy-storage

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