Deeming export of electricity for feed-in tariff
Posted by Cathy Debenham on 25 October 2010 at 9:05 am
Deeming is usually associated with the proposed renewable heat incentive, but it is also used in the feed-in tariff to estimate the amount of electricity that is exported to the grid by microgeneration systems.
We recently received the following question: "It would be interesting and informative to find out how many people who have schemes under MCS have been able to get export meters fitted. Which electricity companies have done this and which have 'deemed' 50% off total generation as exported. Little has been written on 'deemed export' electricity, its legislative orgins, and likely future changes in this area."
I asked Ofgem what the situation is - and the answer is that installations of over 30kW must have an export meter. If they are less than 30kW it's optional, but if you do have an export meter you must use it. If you don't, the amount exported will be 'deemed' at 50% for solar PV, wind turbines, and anaerobic digestion; and at 75% for micro hydro.
At the moment it's not the utility companies that define whether or not you have an export meter. It's something which you can arrange with your installer. My solar PV system was installed in February with both generation and export meter (it cost an extra £42 + VAT). I've got a 2.1kW array of solar PV and am exporting more than half of what's generated despite working from home.
However, these rules are likely to change once the general shift to smart meters gets under way. Smart meters will include functionality to measure electricity generated and exported. I understand that some utility companies are installing smart meters now for customers who have microgeneration, even though the government is still consulting on the roll out of smart meters an there isn't yet an agreed standard. If you utility is one of these, do tell us how you're finding the smart meter in the comment section below.
NB: Since writing this blog, I have learned more about the situation - Domestic size installations can only claim the export tariff based on a meter reading if the meter is installed by their electricity supplier, and has an MPAN number. Click here to read more.
Photo by Marco Lazzaroni
If you have a question about anything in the above blog, please ask it in the comments section below.
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