Short answer: commercial and utility storage is specified around what the battery is for — peak shaving, backup, self-consumption, or grid services — and sized on two separate axes: power (kW/MW) for how fast it charges and discharges, and energy (kWh/MWh) for how long. Scaled-up LiFePO4 systems, from stackable C&I units to liquid-cooled 20-ft containers, cover the range from tens of kWh to multiple MWh.
Step 1 — Define the use case
- Peak shaving / demand charge reduction — discharge during costly demand peaks. Needs enough power to cut the peak and enough energy to cover its duration.
- Backup / resilience — keep operations running through outages. Size energy to critical loads × required hours.
- Self-consumption — store on-site solar surplus for later use.
- Grid services / arbitrage — shift energy to high-price periods.
Most C&I projects combine two or more; size for the binding one.
Step 2 — Size power and energy separately
Power and energy are different specifications:
| Axis | What it sets | Driven by |
|---|---|---|
| Power (kW / MW) | How fast it charges/discharges | Peak load, demand-charge cut |
| Energy (kWh / MWh) | How long it can sustain that | Duration of the peak or outage |
A project cutting a short, sharp peak needs high power but less energy; one covering a long evening needs more energy.
Step 3 — Demand the right safety and integration
- Automotive-grade LFP cells with long cycle life and high usable depth of discharge.
- Multi-level safety — smart BMS, gas detection, aerosol suppression and explosion venting on container systems.
- Thermal management — liquid cooling keeps cell temperatures even (small ΔT) for life and performance.
- Certifications — the marks your market and financiers require.
Step 4 — Plan for scale
Choose a platform that scales with the project: stackable units for smaller C&I sites, and 20-ft liquid-cooled containers (up to several MWh each, paralleled) for large C&I and utility installations.
COTECH Solar's storage spans stackable home and C&I systems to liquid-cooled 20-ft containers up to 5 MWh. See Energy Storage or discuss your project with our engineers.
FAQ
How do you size a battery for peak shaving?
Size on two axes: enough power (kW/MW) to cut the peak demand, and enough energy (kWh/MWh) to sustain that reduction for the length of the peak. Analyse the site's load profile to find how high and how long the peaks are, then specify accordingly.
What's the difference between power and energy in a storage system?
Power (kW/MW) is how fast the battery can charge or discharge; energy (kWh/MWh) is how much it can store and therefore how long it can sustain that power. A system cutting short peaks needs high power; one covering long durations needs more energy.
What safety features should utility storage have?
Look for automotive-grade LFP cells, a smart battery management system, and multi-level protection — gas detection, aerosol suppression and explosion venting — plus effective thermal management (liquid cooling) and the certifications your market and financiers require.