What it does
The levelised cost of energy (LCOE) is the price per MWh at which a power plant would exactly pay back everything it costs over its life, once money in the future is discounted. It lets you compare plants with very different cost patterns: a solar farm that costs a lot up front and almost nothing to run, against a gas plant that is cheaper to build but burns fuel every hour.
LCOE = (capital + Σ discounted yearly costs) ÷ Σ discounted yearly energy
This calculator gives:
- the LCOE per MWh and per kWh, and a shortcut value from the capital recovery factor;
- how it splits into capital, fixed O&M, variable O&M and fuel;
- a tornado chart: the LCOE when each input moves up and down by the same share, biggest effect at the top;
- the cash flow year by year (energy, each cost, discount factor and present values), as a table and a CSV.
How to use it
- Pick an example plant to start from (all made up), then type your own values. Use one currency throughout.
- Capital cost is the overnight cost per kW, spent at year 0. Fixed O&M is per kW per year; variable O&M per MWh generated.
- Fuel: price per GJ of fuel times the heat rate (GJ of fuel burned per MWh of electricity). Set the heat rate to 0 for wind, solar and hydro.
- Capacity factor sets the energy: MW × 8,760 hours × capacity factor in year 1. Output loss lowers it each year (solar panels lose roughly half a percent a year).
- Discount rate: use a real rate if costs are in today’s money, or a nominal rate together with a cost rise equal to inflation.
Energy and running costs are counted at the end of each year; there is no build period, tax, subsidy, debt structure or end-of-life cost.
Worked example
The made-up solar farm: 50 MW, 1,000 per kW, 15 per kW per year fixed O&M, no fuel, 22 % capacity factor, 0.5 % output loss a year, 7 % discount rate, 30 years. It makes 96,360 MWh in year 1 and 2,690,676 MWh over its life (1,139,584 MWh discounted). The present value of all costs is 59,306,781, so the LCOE is 52.04 per MWh (0.0520 per kWh): 43.88 from capital and 8.17 from fixed O&M. The capital recovery factor at 7 % over 30 years is 0.08059, and the shortcut LCOE (no output loss) is 49.60. The tornado shows the capacity factor matters most: ±20 % moves the LCOE from 65.05 to 43.37.
The made-up gas plant comes to 71.05 per MWh, of which 46.42 is fuel, so its fuel price and heat rate top the tornado.
FAQ
Why is LCOE not the whole story? It ignores when the energy comes (solar at noon is worth less than power on a winter evening), grid costs and backup. Use it to compare like with like.
Is my data uploaded? No. Everything runs in your browser and works offline.
For study and planning; check real projects with your own quotes and a qualified adviser.
Where the numbers come from
- Own code: the standard LCOE definition (present value of lifetime costs divided by present value of lifetime energy) and the capital recovery factor, as found in energy economics textbooks.
- Checked against a separate NumPy calculation on the three example plants and five random input sets (agreement to 1 part in 10 billion), and against the annuity formula when there is no output loss or cost rise.
- The example plants (solar, wind, gas) are made-up round numbers for fibub, not market prices, study results or agency figures.
Standard scientific values, such as constants, atomic weights and melting points, are facts found in every textbook; we name where ours were checked. If you are an author or publisher and want a value, a credit or a table changed or removed, tell us and we will act quickly.
Last updated 2026-11-09.