Well here goes, I've had to use the calculator so hopefully all figures are correct. If you notice any glaring mistakes feel free to let me know, maths has never been my strong point.
The two weeks before we had the panels fitted we consumed:-
How we work out exactly how much we are reducing our electricity cost is a little difficult to calculate as there could be times when we do not use absolutely all of the energy generated. I thought instead, simply as an interesting exercise, I'd contrast last year's readings from our electricity meter against this year's readings.
October 1st Week 2nd Week 3rd Week 4th Week Total Used
2010 183 223 270 237 913
2011 137 119 135 203 594
In short a saving of 319 kWh. All the reduction of kWh usage in this comparison obviously cannot be put down solely to the installation of the solar PV panels, other variable factors should be taken into account. For example; external temperature conditions, general home energy conservation strategies implemented, whether we were home in the evenings etc. Still I like the figures.
One last little thing. I still haven't got used to seeing how our home energy monitor now sometimes goes down when we switch a light on. That's simply because when we are generating more than we are using the monitor reflects the credit available. When we switch something on, the figure on the monitor reduces because that electrical item consumes some of the generated electricity available for free use.
There is a rumour that from December 12th 2011, the tariff payment will reduce to 21p/kWh for solar photovoltaic systems of up to 4kW. I found this information on the energy saving trust website, note that this proposal is not final.
Falling costs in solar installation, (the Government) quoting a fall from £13,000 to £9,000 for an average system since the tariffs began, mean that homeowners should still see a decent rate of return on their investment, quoting figures of around 5% return. But that's well shy of the 10% return owners are currently getting. In short if you are considering it ACT NOW.
Bear in mind too that it can take some time for your application for FITs to be received by your FIT licensee (FIT electricity supplier). It will of course always be after the date on which your PV system is installed.