I beleive its only export meter if you've got one fitted.

Export metering is only compulsory on systems over 30kW - whether domestic or commercial matters not. Anyone can get an export meter installed if they want (and are prepared to pay for it sometimes), although it may not be to the owners advantage to do so.

Deeming is 50% for everything apart from hydro where it is 75%.

These figures are all laid down by DECC.

A point usually missed in payback calculations is that these figures can be changed at any time. Once SmartMeters are rolled out the deeming should disappear.

Thaanks all. Ted, thanks for conf of the cut-off - one of the set-ups is 50kW.

When I looked for an Electricity suppler only one would fit an export meter on my 11kW system (Gaia wind turbine) and that was SSE and they tried to back out at the last minute. I think they know it must be in their favour to deem the 50% otherwise they would be happy to fit them. Lets face it , if you have PV on your house and are at work all day then you will use hardly any of your generation.
Turns out we export nearly 90% of our generation so we would be giving SSE 40% of generation without an export meter. No wonder they will no longer fit export meters on systems below 30kW!

The rip off for export meters is there but notm quite as bad as Ted had from eon. I have been quoted about £600 pa for a 40kWp system. As we buy a lot of juice through the same people I am working on getting that down to a realistic figure. But if you think it is bad for elec metering don't go into getting new gas meters for industrial use. Gas is too cheap per kWh so they make it on the costs of installing and letting you have access to the stuff for the larger than normal consumer. Then when you don't use what they think you may use they bill you some more for not using it!

SMART METERS I don't think the gov or the electricity suppliers have actually sorted out the specs for a 'national standard' smart meter. If what I have read so far is correct, there do not seem to be great advantages to the average domestic consumer in getting a meter which only tells the electricity supplier how much you are using on a short timeframe. It saves the individual meter being read and you get an up-to-date bill, but if the van-driving meter reader is reading all the other meters around you, there is no great saving in costs. If we ever get a smart grid, then I can see that a smart meter in each household and business telling a smart grid what is happening could allow far greater control of production, distribution and pricing. If I'm around to see it, I will be impressed! (or very old )

50% Deemed Export My 4kW PV system exports more than 50% of production, based on a couple of months running. When I get a few more figures, I'll sit down and work out whether to ask about having an export meter fitted (or installing a stored DHW water system with an immersion heater). I suspect it won't be worth it.