Tasuvusaeg http://www.eupvplatform.org/fileadmin/Documents/Brochure-indicateurs_26_pays.pdf

http://www.eupvplatform.org/fileadmin/Documents/Brochure-indicateurs_26_pays.pdf


The energy pay-back time (EPBT) of a complete PV system
(not only panels, but also wires and electronic connexion devices)
is, depending on the solar irradiation of its location, in the range
of 19 months (just over one year and a half) to 40 months
(three years and 4 months) for a roof-mounted system, and from
32 months (2 years and 8 months) to 56 months (4 years
and 8 months) for a PV-façade.
Based on a commonly admitted 30 year-long commercial
life cycle, the energy return factor (ERF) is between 8 and 18
for roof-mounted systems, and between 5.4 and 10 for façades.
Varying widely from one country to another, using the energy
production mix from each country, 1 single kW of PV
panels (roughly 10 square meters) can avoid up to 40 tons
of Carbon dioxide (CO2) during its whole commercial life
cycle - 23.5 for a façade

Helsinki
Global horizontal irradiation
956 kWh/m²
Roof-top Façade
Annual output [kWh/kWp] 825 602
Energy Pay-Back Time [years] 3,06 4,19
Energy Return Factor
[number of times] 8,8 6,2
Potential for CO2 mitigation
[tCO2/kWp] 7,780 5,683

In central Europe a 3 kWp rated solar electricity system, with a module area of approximately 27 square metres, would produce enough power to meet the electricity demand of an energy conscious household.