Official PV generation figures
The official figure used for calculating how much electricity will be generated by a PV system is 800kWh per kWp. This works out as follows:
- A 1kWp PV system produces 800kWhs per year
- A 2kWp PV system produces 1600kWhs per year
- A 3kWp PV system produces 2400kWhs per year
- A 4kWp PV system produces 3200kWhs per year
This figure is based on the SAP2005 calculation for energy in buildings document.
Why do we show higher generation figures?
The official figures used are a bit out of date now. PV systems are better now than in 2005.
In our experience, we have found that a well designed, south facing, unshaded PV system will produce 850kWhs per kWp. The figures we have used on our site to calculate savings and earnings we feel are more realistic than the dated offical figures. By using more realistic figures, the Feed in Tariff amount and the electricity saving amount are more realistic. The generation figures we use work out as follows:
- A 1kWp PV system would produce 850kWhs per year
- A 2kWp PV system would produce 1700kWhs per year
- A 3kWp PV system would produce 2550kWhs per year
- A 4kWp PV system would produce 3400kWhs per year
Systems can generate less or more than these figures. A 3kWp PV system that we designed and installed has actually generated 2700kWhs a year, two years running.
Figures on Quotes
Having said that, all quotes we produce must state system generation figures using the official SAP2005 figure. Hopefully these official figures will be updated at some point.