This guide covers solar plus storage in plain terms. For a commercial building owner, solar alone saves money on energy. Adding storage can save on something just as costly: demand charges.
What demand charges are for solar plus storage
Many commercial utility bills include a fee based on the highest power draw in a billing period. A short spike can set the charge for the entire month. Batteries can discharge during those peaks and lower the bill.
What solar plus storage does
Solar produces energy during the day. Batteries store extra solar power or charge from the grid when rates are low, then supply the building when rates are high. The system can also keep critical loads running during an outage.
Questions to ask for solar plus storage
What is the rate structure? How much roof or land is available? What incentives apply? How will the system be maintained and monitored? A good installer will model the building load before sizing equipment.
Who it suits
Warehouses, cold storage, manufacturing, schools and hospitals often have the load profiles and roof space to benefit. As battery prices have fallen over the past decade, the business case has improved for a wider range of buildings.
Why add storage to solar for solar plus storage
Solar produces most when the sun is high, but building demand often peaks later in the day. A battery stores midday output and releases it when electricity is most expensive or when the grid is stressed. That can reduce demand charges, which make up a large part of many commercial bills.
Questions to ask before you buy
Look at your load profile, your utility rate structure, available incentives and roof or land space. Ask installers for a modeled savings estimate based on your actual interval data, and compare more than one quote. Check warranty terms, expected battery life and what happens during an outage.
Resilience is part of the value
A system designed with backup in mind can keep critical loads running during an outage. For a business where downtime costs real money, that peace of mind can matter as much as the monthly savings.
Related reading
For more, see our guides on the business case for efficiency upgrades and batteries and the grid. For background from an outside source, visit the U.S. Department of Energy.
