Define the duty first
Peak support, solar shifting, generator optimisation, short-duration resilience and longer backup are different jobs. Each creates a different relationship between battery power, battery energy and control strategy.
ENGINEERING GUIDE / BATTERY STORAGE
Size battery power and battery energy separately.
Battery storage is defined by both power and energy. The correct configuration depends on what the battery is expected to do, how long it must do it and how often that duty repeats.
Power answers how much
A battery rated at 500 kW can provide up to that level of instantaneous support subject to inverter and operating limits. Power rating is therefore linked to the size of the load event or dispatch contribution the battery must cover.
Energy answers how long
A 1 MWh battery could theoretically support 500 kW for two hours before losses and operating limits are considered. Usable duration depends on allowed state-of-charge range, efficiency, reserve margin and degradation strategy.
Cycle strategy affects value
Frequent cycling can create more savings but also changes thermal duty, degradation and replacement assumptions. The financial model should use the expected operating pattern rather than an idealised one-cycle-per-day assumption unless that is the actual dispatch plan.
Integrate with the wider plant
Storage controls must coordinate solar output, firm generation, grid availability, load priority and protection. The battery should be treated as part of the power system rather than an isolated container with a headline MWh figure.
ENGINEERING BASIS / PUBLIC NOTE
Built from operating questions, not equipment catalogues.
This page explains the engineering logic used to frame an early power decision. Final sizing, commercial terms and detailed design depend on verified project data, site conditions and formal engineering work.
- Technical content owner
- Mergen Power
- Market focus
- Nigeria
- Public contact
- info@mergenpower.com
- Page updated
- 7 August 2026
FIRST DECISION BASIS
Inputs that materially change the answer.
These are the early inputs Mergen would normally test before treating a configuration as a credible project basis.
01Required battery kW
02Required duration
03Cycle frequency
04State-of-charge window
05Load or solar profile
06Control objective
PROJECT QUESTIONS
Questions owners and project teams ask.
How long will a 1 MWh battery last?
Duration depends on discharge power and usable energy. At a simple 500 kW discharge, 1 MWh is two theoretical hours before losses, state-of-charge limits, reserve and degradation allowances are considered.
Should storage be sized from solar capacity or from load?
The duty should drive the size. Solar output matters when the battery is shifting or firming solar energy, but the required kW, kWh and control logic still need to be reconciled with the load and reliability objective.
Why is usable battery energy lower than the nameplate figure?
Operating limits normally preserve a state-of-charge window, and conversion losses, reserve, temperature and degradation allowances can reduce the energy available for the intended duty.
What data is needed for an initial battery assessment?
Load profile, peak demand, current generation or grid supply, solar profile if applicable, required duration, cycling expectation, critical-load requirement, energy cost and the intended commercial objective are key inputs.
START WITH THE LOAD
Bring the operating problem.
Send the State or FCT, demand, operating hours, current supply and reliability requirement. Mergen can use that as the first engineering basis.