MW to MWh calculator

Power × duration = energy. Convert either direction at any duration, then size the site from the result.

Convert
Duration
Energy capacity400 MWh100 MW × 4h

MW is the rate the system can charge or discharge at; MWh is how much energy it stores. Energy = power × duration at rated output.

How it works

  1. 1
    Pick the directionMW → MWh when the project is specified by power, MWh → MW when it is specified by energy.
  2. 2
    Set the durationHours at rated output. 2 and 4 hours cover most grid-scale BESS; 1- and 8-hour durations are included for shorter and longer builds.
  3. 3
    Size the site nextWith the MWh known, the land area and equipment calculators turn it into acres and an equipment list.

Frequently asked questions

What is the difference between MW and MWh?

MW (megawatts) is power — the rate at which the system charges or discharges. MWh (megawatt-hours) is energy — how much the system stores. A 100 MW / 400 MWh BESS can deliver 100 MW continuously for 4 hours.

How do you convert MW to MWh?

Multiply power by duration: MWh = MW × hours at rated output. A 50 MW system with 2-hour duration stores 100 MWh; with 4-hour duration, 200 MWh. The reverse is MW = MWh ÷ hours.

What does 100 MW / 400 MWh mean?

A system rated to charge or discharge at 100 MW, storing 400 MWh — a 4-hour duration (400 ÷ 100). Both numbers together specify a BESS; either one alone does not.

What durations are common for grid-scale BESS?

Most current grid-scale procurements specify 2-hour or 4-hour systems; longer durations appear where capacity markets or resource adequacy rules reward them. Physically, duration is set by how many DC blocks share each PCS — the same 6.25 MWh containers serve either duration.

Does duration change the equipment on site?

The energy fixes the DC block count. The duration sets the power rating and shifts some PCS & MV skid formats — a Twin cluster takes a 40 ft skid at 2 hours and a 20 ft skid at 4 hours — so a 2-hour system of the same energy carries more PCS capacity, not more containers.

Related

BESS land area calculatorTurn the MWh into acres, calibrated against real layouts.BESS equipment calculatorDC blocks, PCS & MV skids, and E-house for the capacity.The layout modelHow power, energy, and equipment become a packed site layout.

With the capacity settled, the layout tool turns it into a site layout: draw the boundary and the solver packs equipment, roads, fence, and gate.

Start a layout