Recommended default: 1300 €/kWp, indicative Belgian turnkey cost for a quick community screen.

Cost of the PV system per kWp of peak power, not the total bill. The tool multiplies this by total community capacity: e.g. 1300 €/kWp × 300 kWp = 390 000 €.

Consider installer quotes and whether one plant vs many rooftops changes €/kWp. Optional O&M and subsidy are under Advanced financial assumptions.

Recommended default: 0.35 €/kWh, indicative Belgian household all-in retail price for screening.

Reference price for 1 kWh bought from the grid (what participants would pay without sharing).

Prefer a representative all-in bill price. Consumer savings compare this with the shared electricity price below.

Used for net gain (NPV) only: it converts future yearly savings into today’s money. A euro saved in year 10 counts for less than a euro saved next year.

Ask: “If we do not invest in this community PV, what return could we reasonably expect with the same money?” That return is your discount rate. Examples of “elsewhere”:

• Safe: government bonds, savings accounts, term deposits, often around a few percent (e.g. ~2–4% in quiet periods; higher when interest rates rise).
• Middle: a mix of bonds and cautious investments, often around ~4–6%.
• Riskier: diversified stock markets, long-run expectations are often higher (e.g. ~6–8%+), but not guaranteed year to year.

Recommended default: 5%, middle-ground screening value (not bank or investment advice). Use lower (e.g. 2–3%) for low-risk alternatives; higher for riskier opportunity cost. Higher rate → lower project NPV and often a smaller “best size for money”.

Payback time does not use this rate.

Recommended default: 25 years, common economic / warranty horizon.

Consider a shorter horizon for a more conservative investment screen. Degradation is set under Advanced financial assumptions.

Recommended default: 0.04 €/kWh, low residual injection value for a conservative screen.

Compensation received for PV electricity that cannot be shared locally and is injected into the grid.

Consider your injection tariff (or 0 if none). Shared energy uses the prices in Energy sharing economics below.

Recommended default: 0.19 €/kWh, example shared price between residual export and grid retail.

Price paid by participants for electricity shared within the community.

Consider keeping it below the grid reference so consumers save, and above producer remuneration so the community balance can stay positive.

Recommended default: 0.12 €/kWh, example local remuneration above residual export.

Amount received by the producer for each kWh shared locally.

Consider setting it above residual export (so producers gain vs injection) and at or below the shared price (so the community balance can work).