In brief · Dutch commercial installations
Size the problem first, then the battery.
kW measures charging or discharging power at a particular moment. kWh measures the amount of energy a battery can store. A system needs enough instantaneous power and usable stored energy to meet its purpose. The right size varies considerably between peak shaving, increasing solar self-consumption and energy-price optimisation.
What is the difference between kW and kWh?
Suppose your company temporarily needs 30 kW more than the power you want to draw through its connection. If that peak lasts two hours, the theoretical energy needed to cover that part of the demand is 30 × 2 = 60 kWh. This is only the energy balance of the example; it is not a final battery specification.
Real systems must account for available charging and discharging power, conversion losses, usable depth of discharge, temperature, ageing, reserve margins and the next opportunity to recharge. Several peaks within a day may require a different battery size from one isolated peak.
What should the battery actually do?
Peak shaving
The battery temporarily supplies power when several consumers operate at the same time. The essential information is not only the highest peak but also how long it lasts and how often it occurs.
Increase on-site use of solar electricity
A battery can store surplus generation during the day for later consumption. Hourly or 15-minute solar and business demand profiles are important here. A large PV installation does not automatically justify a large battery.
Energy trading and price optimisation
With an appropriate energy contract, price differences may provide value. Before making a business case, include energy and conversion losses, battery wear, taxes, grid charges, possible trading fees and contractual limitations. A gross electricity price spread is not guaranteed net profit.
What information is needed before sizing a battery?
- Existing electrical connection rating, physical limitations and contract conditions
- 15-minute or other suitably detailed electricity consumption data
- Solar PV generation profiles and any export restrictions
- EV charging needs, operating hours, seasonal patterns and expansion plans
- Available space, fire safety requirements, access and desired operational resilience
- The investment objective, expected service life and maintenance strategy
These inputs make it possible to compare realistic alternatives: energy management without storage, a smaller battery combined with controls, larger storage, or adjustments to business processes.
When is a commercial battery financially viable?
There is no universal payback period. Results depend on the number of useful cycles, power peaks actually avoided, the value of additional solar self-consumption, contract terms and total lifetime cost. Degradation, insurance, monitoring and electrical installation modifications must also be considered.
A dependable business case should include at least a base scenario, a sensitivity analysis and stated assumptions about electricity prices and operation. An energy management system (EMS) may be needed to control the battery according to its intended function, but it is not the battery itself.
Frequently asked questions
Can I select a battery based on annual electricity consumption?
No. Annual consumption says little about the height and duration of power peaks. Proper sizing requires demand profiles and a clearly defined use case.
Is a 100 kWh battery the same thing as a 100 kW battery?
No. kWh describes energy capacity; kW describes power. A battery with a 100 kWh energy capacity may have a maximum output power well below 100 kW.
Can a battery replace a larger electricity connection?
In some cases, storage can reduce a power bottleneck or postpone an upgrade. The outcome depends on peak duration, frequency, predictability and opportunities to recharge. The Dutch grid operator's rules and the site's electrical limits still apply.