Solar capex and opex calculator

Capex per watt, year-1 opex, LCOE and simple payback for a stated project. Move a cost between lines or years and see what changes.

A design aid, not financial advice. All inputs are in constant (real) USD, before tax, with no incentives and no debt. Capex is paid at year 0. Opex and energy fall at each year end. Defaults are the page example, not market prices.

Presets:

Project and energy

Size (kWdc) Year-1 yield (kWh per kWdc) Degradation (% per year) Life (years, 1 to 50) Real discount rate (%) Energy value (USD per kWh, flat real)

Capex lines (USD per Wdc, paid at year 0)

Modules Inverters Racking and foundations Electrical balance of system Installation labour Interconnection and permitting Developer and EPC overhead and margin Contingency

Opex lines (USD per year, year 1, constant money)

O&M contract and cleaning Monitoring and asset management Insurance Land lease Other annual fee Pay the land lease for the whole life at year 0 (moves it into capex)

One-off replacement

Inverter replacement cost (USD) Replacement year (0 = paid at year 0)

Capex	- USD (- USD per Wdc)
Year-1 opex	- USD (- USD per kWdc-yr)
Lifetime cash cost (undiscounted)	- USD
Capex share of discounted cost	-
LCOE	- USD per kWh
Simple payback at the energy value	-

LCOE = discounted costs divided by discounted energy, as on the LCOE page. Simple payback counts undiscounted yearly cash (energy value less opex and replacement) until it repays the year-0 spend.