How to use this calculator
- Enter annual electricity demand on an MWh basis.
- Select the share of demand the PPA should cover.
- Enter expected capacity factor and total delivery losses.
- Adjust for the share of project output under contract.
#1305 · Energy & Environment Tool
Renewable PPA System Sizing Calculator
Estimate the renewable generating capacity needed to supply a chosen share of annual electricity demand through a PPA. The calculator works backward from the energy target and adjusts for capacity factor, delivery losses, and the portion of project output contracted. Results include required megawatts, target annual energy, expected monthly delivery, and the implied project size for partial-output agreements.
Calculator
Capacity planningFormula
Required contracted MW = target MWh ÷ [8,760 × capacity factor × (1 − losses)]
Equivalent project MW = required contracted MW ÷ contracted share
Equivalent project MW = required contracted MW ÷ contracted share
What the result means
Required capacity is the nameplate megawatts needed to produce the annual energy target under the stated performance assumptions.
Hourly load matching, seasonal production, basis risk, and certificate treatment require a time-series procurement analysis beyond this annual energy balance.
Example calculation
Covering 80% of 100,000 MWh with a 35% capacity factor and 5% losses requires about 27.46 MW of contracted capacity.
Tips for better results
- Use recent normalized annual load data.
- Choose a technology- and location-specific capacity factor.
- Include expected curtailment and delivery losses only once.
- Follow annual sizing with an hourly matching study.
Frequently asked questions
Does this PPA sizing calculation guarantee hourly renewable matching?
No. It balances annual energy only; hourly and seasonal alignment require interval load and generation profiles.
How does a partial contracted output share affect project size?
The required contracted capacity is divided by the output share to show the larger equivalent project nameplate capacity.
Does the renewable PPA system sizing calculation result include taxes or financing?
No. The estimate does not model market settlement or hourly shape risk. Add taxes, financing costs, incentives, and contract-specific charges separately when they apply.
Can I enter decimal values in this renewable PPA system sizing calculation?
Yes. Decimal inputs are supported, and the calculator keeps full precision until results are displayed.
What happens if I enter zero?
Zero is accepted where it represents a valid operating condition. A value that would make the formula undefined triggers an input message instead of showing an invalid result.
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Variables and units
| Variable | Meaning | Unit |
|---|---|---|
| D | Annual electricity demand | MWh/year |
| T | Target coverage | % |
| CF | Expected capacity factor | % |
| L | Delivery and curtailment losses | % |