Attacks the demand charge directly
Solar reduces energy charges. Storage is what reduces the dollars-per-kW line, which on some commercial bills is the larger of the two.
Solution
Battery storage and demand management
A battery is rated in two numbers that do different jobs. Usable energy in kWh decides how long it can run. Continuous power in kW decides how much it can shave. Buying the wrong one of those is the most expensive mistake in commercial storage.
- Typical range
- 100 kWh to 4,000 kWh usable
- Built for
- Cold storage, processors, pump stations, critical facilities
Overview
What this actually involves
On a commercial tariff, a large slice of the bill is not energy at all. It is a demand charge, billed in dollars per kW against your highest 15-minute average demand in the month. One compressor start on a hot afternoon can set that number and you pay for it across every day of the billing period.
Solar alone does not fix demand charges reliably, because your peak can occur at 7pm when the array is finished for the day. Storage does, if it is sized correctly: the battery discharges into the peak, the meter sees a flatter curve and the demand charge falls.
The second job is arbitrage. Under a commercial time-of-use tariff, energy in the 4pm to 9pm peak window costs substantially more than energy at noon. A battery charged from midday solar and discharged into the peak window moves kWh from cheap hours to expensive ones, every single day.
The third job is resilience. Refrigerated storage, irrigation controllers, process tanks and server rooms do not tolerate an outage gracefully. We separate those circuits onto a backup panel and size the battery against their real running and surge loads rather than the whole building.
Scope of supply
What is included
- Interval-data analysis of twelve months at 15-minute resolution to find the true demand peaks and their causes
- Demand-shaving model: kW of discharge needed, for how many minutes, how often per month
- Time-of-use arbitrage model against your actual tariff periods and seasonal rate changes
- Critical-load schedule: every backed-up circuit with running watts, starting surge and hours per day
- Battery sizing in usable kWh and continuous kW, with round-trip efficiency and depth of discharge stated
- Inverter and transfer equipment selection, protective relaying and NEC 706 compliance
- Fire-code review: NFPA 855 separation distances, ventilation, detection and the local fire marshal's requirements
- Cycling strategy programmed, reviewed after 90 days of live data and retuned
Sequence
How it runs
- 01
Bill and interval forensics
We take your last twelve bills apart line by line and load the interval data. Most of the answer is already in there.
- 02
Sizing in kW and kWh
Two independent numbers: the power needed to shave the peak and the energy needed to hold it. Both are modelled, neither is guessed.
- 03
Siting and fire review
Indoor or outdoor enclosure, clearances, ventilation and an early conversation with the local fire marshal.
- 04
Install and integrate
Battery, inverter, critical-load panel and controls, then commissioning against the modelled dispatch schedule.
- 05
Tune on real data
After 90 days we compare modelled and actual demand reduction and retune the dispatch thresholds.
Why it works
What you get out of it
Moves kWh from noon to the peak window
Charge cheap, discharge expensive, every day, automatically, with no change to how the facility operates.
Keeps the critical circuits alive
Refrigeration, controls and process loads ride through an outage on a properly sized backup panel.
Storage-specific incentives may apply
California's Self-Generation Incentive Program has historically supported commercial storage. Amounts and eligibility change: treat any figure we show as a sample and confirm current terms.
What moves the price
Cost and schedule drivers
| Factor | Effect on the project |
|---|---|
| Peak shape | A short sharp peak needs kW. A long broad peak needs kWh. The shape decides the money |
| Tariff spread | The wider the gap between off-peak and peak energy rates, the more each stored kWh is worth |
| Critical load list | Every circuit added to the backup panel raises both the kW and the kWh you must buy |
| Motor starting surge | A compressor can draw several times its running current for a few seconds, which sets the inverter class |
| Fire code and siting | NFPA 855 clearances and the local fire marshal's position can decide indoor versus outdoor and the enclosure cost |
Often paired with
Related solutions
Answers
Battery storage and demand management: common questions
Not covered here? Our engineers answer directly, not through a call centre.
Ask a question(661) 555-0183kW is a rate of power, like the speed of a tap. kWh is a quantity of energy, like the water in the bucket. A battery rated 250 kW / 500 kWh can deliver 250 kW for two hours, or 125 kW for four. Demand charges are billed against kW. Energy charges are billed against kWh.
For the critical-load panel, usually yes for hours. For the whole facility, usually no. A 500 kWh battery serving a 150 kW facility load lasts a little over three hours. That is why we build a critical-load schedule first.
Yes, with the right inverter architecture and an islanding-capable system. That is a design decision that must be made up front, not retrofitted.
Commercial lithium iron phosphate systems are commonly warranted for roughly ten years or a stated throughput in MWh, with an end-of-warranty capacity figure. Daily arbitrage cycling counts against that throughput, so we model the cycle plan against the warranty rather than assuming one fits the other.
Bring us the bill before you bring us the roof
Every project starts with twelve months of interval data and a load shape. The array comes after that, sized to what you actually use.
CSLB #1071482 (sample). Prevailing wage on public works. Engineers answer, not a call centre.