27 Aug '09: We have accepted a quotation from EvoEnergy for 17 Photovoltaic panels to go on the roof as the first stage in this project. This is a separate wiring/plumbing operation from the Solar geocharging, so the PV installation can go ahead in September. The installation is calculated to be 3.06 KW optimally, equivalent over an average year on a roof of our pitch and orientation to be generating 2270 kWhr/year.
On the new feed in tariffs of next April of 36.5p p/kWhr for retrofit PV, this is equivalent to earning and savings of £1032 a year. We presently burn a precise total of 8500 kWhr per annum. That means we would still be needing to buy power from the grid, costing us £1100 /annum. So from the start of April, we would nearly be electricity neutral, ie earning the same as we spend. If Solar earth charging cuts that amount by only 10%, that will make us electricity negative, i.e. minus quantity electricity bills.
The grid electricity we get is from Good Energy, which is 100% renewables. Even before April 2010, Good Energy have a scheme to offer preferential tariff of 15p/kWhr before April 2010.
All this does not make the house carbon zero in the true sense, but it does if you allow in the mathematics of tariffs and offset.
We have had approval for a grant from the Low Carbon Buildings programme. For anybody reading this, please note that we are in a very beneficial timeframe. If you have PV installed now you qualify for a grant that is not likely to be available when the new Feed in Tariff starts in April 2010.