From yearly electricity use to system size, number of modules, roof area and cost. Deutsch: Von deinem Jahresverbrauch zur Anlagengröße, Modulzahl, Dachfläche…
# How many solar modules do I need?
# Start from your yearly electricity use and work out size, modules and roof area.
# Example values, check them for your case.
# Inputs
# 3500 kWh is the household reference of the BDEW Strompreisanalyse
yearlyUse = 3500 kWh
# Share of your use you want to cover with solar
coverage = 70 %
# Full-load hours per year (yearly yield per installed kW).
# Fraunhofer ISE (as summarized by reduco.ai): rooftop fleet average about 922 h, south-facing 935 h (north) to 1280 h (south)
fullLoadHours = 920 h
modulePower = 430 W
moduleArea = 1.9 m^2
# Assumption: check current quotes, prices differ a lot by size and installer
pricePerKw = 1400 € / kW
# Needed system
neededYield = yearlyUse * coverage
neededPower = neededYield / fullLoadHours to kW
modules = ceil(neededPower / modulePower)
# What that means in practice
realPower = modules * modulePower to kW
roofArea = modules * moduleArea
cost = realPower * pricePerKw to €
dailyAverage = realPower * fullLoadHours / (365 days) to kWh / day