How Portuguese Electricity Tariffs Change Solar Payback

The bill items that matter Look for contracted power, energy price by period, fixed charges, taxes and whether the plan has simple, bi-hourly or tri-hourly periods. Solar usually offsets daytime kWh first. If your expensive period is evening, a solar-only system may help less than expected unless loads can move or storage is justified.

A simple homeowner exercise Take twelve months of bills and mark daytime-flexible loads: pool pump, dishwasher, EV charging, water heating, laundry and air-conditioning pre-cooling. Then ask the installer to model savings under your actual tariff and under one alternative tariff. ERSE points consumers to its energy price simulator for comparing offers, which is useful before final system sizing.

Why incentives should not drive the design The Fundo Ambiental lists support notices, but availability changes. A system should make operational sense without a promised future grant. If support appears, it can improve the return; it should not justify a poor roof layout or oversized battery.

Questions for the quote review - Which tariff did the savings model use? - What happens if I change supplier? - Are taxes and fixed charges included correctly? - How much production is exported? - Does the quote separate gross production from bill savings?

Bottom line Before comparing panel brands, compare assumptions. A modest system matched to a real tariff and flexible loads can outperform a bigger system sold with vague savings numbers.