Second Year End Figures Are In...

[MicraShed]

Year One (2012 - 2013) gave a total income from the Norweb Federation of £455
Marry in to this a saving of £80 in gas (based on a reduction in use from 2011-2012) and £90 electricity total income from the system was £625 (12.5% return on investment)

Total Generation was 13 KWh over SAP

Year Two (2013 - 2014) gave a total income from the Norweb Federation of £460
Marry in to this a saving of £95 in gas (based on a reduction in use from 2012-2013) and £110 electricity total income from the system was £665 - (13% return on investment).

Immersun was able to utilise 333KWh - sadly couldnt use more as I physically couldnt use all the water heated.

Total generation was 15 KWh UNDER SAP

I feel my SAP estimates are a tad optimistic as they have me generating 20 KWh in December when the most I have ever done is 4 KWh - 2.5KWp system NW England - SSE facing (tree shade affects it in winter due to sun angle).

 

[Sunshine777]

Not to p*ss into your chips but...

how do you calculate your gas savings as £80 or £95 (2000 kWh or 2376 kWh at 4p/kWh) if the immersun only used 333 kWh of PV?
and the winter of 13/14 was noticeably milder for most parts of the UK than the previous winter

 

[MicraShed]

Im basing my gas savings solely on the difference in gas used between years, and the cost for this gas used (at 11.15p/KWh - Scottish Power inc standing charges) rather than the equiv electricity KWh unit cost.

As I keep month by month figures I know the bulk of my savings have come from when I switched the GCH off and am using only the PV to heat the water, and whilst over winter we used marginally less gas than the previous year, it was only marginally and certainly not as much as you may be thinking.

The figures may not be as great as some peoples installs, but on the whole I am quite happy with the returns so far. I am especially happy with the returns from the Immersun.

 

[The Solar King]

The level of savings is undoubtedly correct, it is how they have occurred that is interesting. I can understand Sunshine 777's incredulity. It is unlikely they are all a result of the PV or the proportional controller.

Time and again there is anecdotal evidence that fitting Renewables leads to the link being made between the light switch and the monthly direct debit. Once this connection happens, behaviour change manifests itself and becomes easy. The fact that monthly records are kept helps to show this (although I don't know how long Micra has kept them). This is one benefit of PV we cannot sell and currently cannot quantify.

 

[MicraShed]

The level of savings is undoubtedly correct, it is how they have occurred that is interesting.

Time and again there is anecdotal evidence that fitting Renewables leads to the link being made between the light switch and the monthly direct debit. Once this connection happens, behaviour change manifests itself and becomes easy The fact that monthly records are kept helps to show this (although I don't know how long Micra has kept them). This is one benefit of PV we cannot sell and currently cannot quantify.

Ive kept monthly consumption records of gas and electricity for five years now, and up to the installation of renewables they were both steadily climbing (gas more than electricity).
I agree that just fitting the PV and Immersun wont have saved all the money - some of it is from changed behaviour ( such as running electrical items in tandem rather than at the same time, reduced energy light fittings, making sure the little darlings are educated about switching things OFF and so on) The PV feeding into the hot water tank means that the tank is running at a higher temp than normal, this means less hot water used for say baths as we use more cold to bring it to the right temp - better insulation has also helped save costs - a few years ago we had building work done which improved the insulation value of the house, there are other small changes too which will have made a difference. The fact that I have used less off the DNO this year despite generating less PV suggests we are getting a bit better at our energy use and not being as wasteful.