Home energy storage battery ratio

How are batteries rated?

Batteries are rated for two different capacity metrics: total and usable. Because usable capacity is most relevant to the amount of energy you'll get from a battery, we like to use usable capacity as the main "capacity" metric to compare storage products. Also, from our energy storage glossary, see how the two terms differ below:

What is battery capacity?

When manufacturers or installers talk about battery capacity (or energy capacity), they usually talk about one of two metrics a battery is rated on: total capacity and usable capacity. We'll get into why those are different further down. For the time being, it's all just "capacity."

What is a battery energy storage system?

A battery energy storage system (BESS) is an electrochemical device that charges from the grid or a power plant and then discharges that energy to provide electricity or other grid services when needed.

How much energy can a battery store?

For most battery systems, there's a limit to how much energy you can store. To store more, you need additional batteries. Even if you don't pull electricity from your battery, it will slowly lose its charge over time.

What is the difference between rated power capacity and storage duration?

Rated power capacity is the total possible instantaneous discharge capability of a battery energy storage system (BESS), or the maximum rate of discharge it can achieve starting from a fully charged state. Storage duration, on the other hand, is the amount of time the BESS can discharge at its power capacity before depleting its energy capacity.

What is the median battery cost on EnergySage?

The median battery cost on EnergySage is $1,133/kWh of stored energy. Incentives can dramatically lower the cost of your battery system.