Therefore the estimated PV array annual output is 3464kWh
This would attract an annual Feed In Tariff of 12.42p x 3454 = £428.98
Assuming that you use 50% (1648 units) of what your installation generates this is
1648 units you do not have to buy from United Utilities at 14p per unit. This would
save you £230.72 (1648 x 14p) and feed back 50% (1648 units) to United Utilities
at 4.85p/unit £79.92
The energy providers have decided to simply pay 50% of whatever you generate annually
at 4.85p per unit.
This saves them having to keep a check on how much you feed back into the grid.
This makes a total income in year one of £739.62
Assuming installation cost of £5,000 this would make the payback period 6.5 years
Assuming installation cost of £6,500 this would make the payback period 8.4 years
The Performance of solar PV systems is impossible to predict with certainty due to
the variability in the amount of solar radiation (sunlight) from location to location
and from year to year. This estimate is based upon the government’s standard assessment
procedure for energy rating of buildings (SAP) and is given as guidance only. It
should not be considered as a guarantee of performance.
Example 16 panel south Facing Roof with no shading