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CeeBee
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« Reply #3 on: January 17, 2012, 09:20:52 AM » |
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Hi
I changed to E7 some years ago - SSE changed the meter for free - I seem to have done OK out of SSE for meters, as I got a free export meter as well, but I don't think they are offering the latter any more.
You have to be certain that E7 is going to benefit you - perhaps at least around a third of your consumption during the cheap 7 hours - do the maths*. It's marginal in my case - relies on the assumption that the greenhouse heaters will use a fair bit in the small hours of the morning when it's cold, but gives me chance to run the washing machine then as well if I want. It slightly complicates the issue of whether to use power when the PV is generating - with a flat rate, then you definitely might as well use your own PV, whereas with E7, if you're going to turn on a load which exceeds the PV generation (not difficult) such that at least some of it is imported at the high rate, then you might be better allowing your PV to export and using the energy at night.
Swapping suppliers shouldn't be a problem, but I don't believe that the FITs payment will automatically transfer with it - the original lot would continue to pay you until a change was explicitly requested, indeed you could change the FIT payment to another company which wasn't the supplier.
3.1p/kWh for export: it's said to be approximately the base bulk price for electricity - i.e. you wouldn't get any more than that if you could sell it separately (as if you ran a power-station or something). The rest of the inflated price for import is to cover distribution, administration, profits, etc.
* The maths if anyone wants a bit of help. Say daytime units cost P pence, E7 cheap units cost E pence, and flat rate units would be F pence. Say you use a proportion N (a number between 0 and 1) of your energy in the cheap period, and therefore (1 - N) in the expensive.
The cross over point is when you're paying the same on either regime: i.e. F = P * (1 - N) + E * N, or rearranging that N = (P - F) / (P - E).
So if for example P was 15p, E was 5p, and F was 12p, then N = (15 - 12) / (15 - 5) = 3 / 10 = 0.3 i.e. you benefit if you use more than a proportion of 0.3 of your energy in the cheap period. Complicated standing charges or initial units that cost more will make it near impossible to calculate properly - luckily I'm with Ebico that have neither of those.
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