Solar solutions
An array sized to the roof is a product. An array sized to your load profile, your tariff and your storage is an engineering decision. We only do the second one.
Complete guide
A photovoltaic cell converts photons into a flow of electrons across a semiconductor junction. Modules aggregate cells into a DC source; an inverter converts that DC into grid-synchronous AC. Everything else in a solar installation exists to make that conversion safe, measurable and durable for thirty years.
Annual irradiance across southern Europe ranges from roughly 1,400 to 2,000 kWh per square metre. Production is the product of that resource, the array's rated capacity and a performance ratio that accounts for temperature, soiling, cabling, inverter efficiency and downtime. We model at hourly resolution, not with annual averages.
Monocrystalline PERC remains the value baseline. TOPCon has largely replaced it in new projects for its lower degradation and higher bifaciality. Heterojunction (HJT) leads on temperature coefficient, which matters in hot climates where cell temperature routinely exceeds 60 °C. Half-cell architecture reduces resistive loss and improves partial-shade behaviour in every technology.
String inverters are the most efficient and cheapest option on a clean, single-orientation roof. Power optimisers add module-level MPPT and monitoring where shading or multiple orientations exist. Microinverters remove the DC string entirely, which suits complex roofs and installations where rapid shutdown at module level is a requirement.
South-facing at 30–35° maximises annual yield, but east–west arrays often deliver better economics because production aligns with morning and evening consumption. Shading is the single most destructive and most underestimated factor: we survey the full solar horizon and simulate obstruction losses month by month before finalising the layout.
Sizing follows the load, not the roof. We analyse a year of consumption data, model self-consumption at each candidate array size, and identify the point where additional capacity stops improving the return. Where a battery is included, that inflection point moves substantially upward.
Survey, structural verification, design, permitting, mounting, module installation, DC and AC electrical works, protections, commissioning, grid registration and handover. Most residential installations are one to three days on site within a three to six week end-to-end process.
DC and AC surge protection, string fusing where required, accessible DC isolation, firefighter rapid shutdown, correctly rated AC protection, RCD selectivity and a measured earthing and equipotential bonding scheme compliant with IEC/EN standards and the Spanish REBT.
Per-string and per-phase monitoring with automated underperformance alerting. Annual inspection covers connectors, torque values, protections and thermographic scanning. Cleaning is scheduled against measured soiling loss rather than a fixed calendar.
Payback in southern Europe currently sits between five and nine years for well-sized residential systems, and three to six years for commercial systems with high daytime load. We model with real degradation, real tariff escalation assumptions and a discount rate, and we identify every applicable subsidy, tax deduction and grant.
Energy payback time for a modern module in southern Europe is under eighteen months against a thirty-year service life. A typical 8 kWp residential array avoids roughly three tonnes of CO₂ per year.
Interactive
Adjust the inputs to see production, savings and payback update in real time.
Estimate annual production, savings and payback for a rooftop array. Figures use an 82 % performance ratio and a 62 % self-consumption rate — conservative, realistic defaults.
Send us a year of electricity bills and a photo of your roof. We return a full engineering proposal with modelled production, savings and payback.
