← Glossary Definition

BESS (Battery Energy Storage System)

A battery energy storage system (BESS) stores electricity for later use, charging when power is cheap or abundant and discharging when it is expensive or scarce. Commercial and industrial sites use BESS to cut demand charges, shift consumption to off-peak rates, provide backup power, and pair with on-site solar.

For commercial and industrial customers, the strongest BESS economics usually come from demand charge reduction. Utilities bill demand charges based on a facility's highest 15- or 30-minute draw in the billing period, and those charges can account for 30-70% of an industrial electric bill. A battery discharges during those brief peaks, shaving the maximum demand the utility sees without changing how the facility operates.

Other value streams stack on top. Time-of-use arbitrage charges the battery at off-peak rates and discharges at peak rates. Demand response programs pay for capacity the battery can shed on request. Paired with on-site solar, storage captures midday generation that would otherwise be exported at low value and uses it during evening peaks. Backup power during outages adds resilience value that's harder to quantify but often decisive for manufacturers.

Whether a BESS pencils out depends on the site's load profile and tariff structure. Sites with short, spiky demand peaks and high demand charges are the best candidates. Interval meter data reveals the shape of those peaks, which is why analysis starts with granular consumption data. Gravity's energy management product combines interval data with tariff detail from utility bills, so teams can screen a portfolio for the sites where storage delivers the fastest payback.

Frequently asked questions

What is a BESS? +

A battery energy storage system (BESS) stores electricity and discharges it later. Facilities use BESS to reduce demand charges, shift consumption to cheaper rate periods, participate in demand response, back up critical loads, and store on-site solar generation.

How does a BESS reduce demand charges? +

Demand charges are billed on a facility's highest 15- or 30-minute power draw. A BESS discharges during those brief peaks, lowering the maximum demand the utility measures. Since demand charges can be 30-70% of an industrial bill, peak shaving is often the largest BESS value stream.

Which facilities are good candidates for battery storage? +

Sites with short, spiky demand peaks, high demand charges or steep time-of-use rate differentials, on-site solar, or critical loads that need backup power. Interval meter data analysis identifies which sites in a portfolio will see the fastest payback.

Related terms

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