Methodology and assumptions of the calculations

All forecast calculations and simulators published on heiwit.com are based on the parameters listed below, unless otherwise stated on the individual page. These are scenario assumptions: they are intended to make the estimates comparable and do not constitute a forecast or a guarantee of return.

Economic parameters

Parameter Value
HEIWIT Commission on the cost of the plant 20 %
HEIWIT Committee on Revenue 20 %
Rent for kWp £15
Rent inflation or surface rights 2 %
Insurance cost for kWp £10
Cost of a photovoltaic system for kWp €850
Value of the kWh fed into the grid €0.08
Inflation on the value of the kWh fed back into the grid 2 %
Fixed markup on kWh sold for self-consumption €0.06

Technical and environmental parameters

Parameter Value
kWp units that can be installed per m² 7 kWp
Annual production loss of the photovoltaic system 0.5 %
CO2 saved per kWh 0.48 kg

Production data source

Photovoltaic yield data comes from PVGIS, the European Commission's Joint Research Centre tool. Reference configuration: location Cremona, tilt 35°, azimuth 0°, PVGIS-SARAH2 database.

Limitations of these assumptions

The values above are averages and represent a national baseline scenario. Actual energy yield varies with latitude, shading, and the actual pitch and orientation of the roof; costs vary with the size of the system and the current market; the value of the energy fed into the grid depends on the commercial arrangement chosen. For an estimate specific to your system, the parameters must be replaced with site-specific data.