Insight · September 12, 2026
Demand charges, and what storage changes
In California, demand charges can be 40% or more of a business electricity bill. Storage and operating changes are how large loads push that number down.
A spike in usage does not have to be a spike in the bill, but only if the tariff charges for the spike and the site has a way to miss it.
In California, demand charges amount to 40% or more of many business electricity bills. They are priced off the highest short interval in the billing period, not off the energy used across the month. A cold-storage pull-down, a shift change at a plant, or a charging window for a fleet can set the bill for the next thirty days.
Who feels it
The pattern shows up at sites with at least about $10,000 a month in electricity and a peaky shape. Typical fits:
- Cold storage and produce processing
- Distribution warehouses
- Manufacturing plants
- Grocery chains and large retailers
- Large wineries
- Car dealerships with charging load
A battery the size of one or two parking spaces, able to cover about two to four hours, can charge off-peak or from on-site solar and discharge across that interval. The grid still serves the facility. It just does not see the full peak.
What this is not
This is not a no-cost program, and it is not an offer to own or maintain equipment on a customer’s site. Those models exclude the municipal and public-power customers this practice is built for. The work here is the assessment: the tariff, the interval data, the interconnection, and whether storage, thermal storage, or a change in operations is the cheaper way to cut the demand the utility has to study.
Solar alone often misses the demand charge, because the peak may fall after the array has dropped off. Solar plus storage is what lines the generation up with the interval that sets the bill. On a San Joaquin County agricultural processor, the Stockton rooftop covers 86% of the site’s energy and saves about $230,000 a year, alongside a separate $200,000+ avoided by keeping the existing switchgear and transformer. Energy savings and interconnection savings are different lines. Both belong in the study.
For the utility
A customer who flattens its own peak is asking for a smaller upgrade. That is the large-load version of the same idea: study the net request, not the nameplate, and write the options down before the design is frozen.