Panels are safe

26 Oct 2011: DNC writes: Some people often ask me, what happens if my panels get stolen, eg off a flat roof?
    I was recently thinking about selling on my PV roof and fitting higher efficiency panels (with liquid cooling), when David Hill of Carbon Legacy pointed out something important, which I recognise as a very good anti theft rule.
   When you have a PV roof fitted, the serial numbers of the panels are registered with OfGem, and that set of numbers is what you use for your Feed in Tariff payments. If those panels turn up elsewhere and someone tries to register them again, they will be flagged up, thus identifying where they got to, and from that, who stole them. The only possible use for second hand panels is for off grid installations. They could not be used for claiming on the Feed in Tariffs. The person buying them would know that they were dodgy and would want to know why.
   For special circumstances, such as you move house and the buyer of the old one doesn't want them, or you have had to replace your panels after a number of years, you would have to make a special case to OfGem to re-register them and re-register at the new location, by the original owner or the executor of the original owner.
   I am quite encouraged by this. It means that if you go on holiday, you feel more confident that your panels are safe, and I am sure that if there are such things as 'panel thieves', they have found this out too. There is more to be made by draining tanks of oil etc. 

Does your meter go in reverse?

19 April : Some people ask if the meter will literally 'go in reverse' if you have a good day of photovoltaic generation.  Mine doesn't, it remains static during the day and only moves forward if we do some ironing or use the kettle a lot, or the heating has to be on. After sunset, it rolls along as a normal one would. Chris Brook of EvoEnergy has provided me with an answer:

"Whether your meter works in reverse depends on the type of meter installed. Old style mechanical meters will run in reverse and people with these will get an extra, though unintended, financial benefit. If you have a more modern electronic meter this will accurately record the units of electricity you import from the grid. It will be stationary if the amount of energy you are producing exceeds your current demand. Your [OfGem] generation meter will tell you accurately how much you have produced. In terms of what you export, this will only be measured accurately if your electricity supplier installs an import/export meter. The only energy provider currently doing this is Scottish and Southern Electricity. Other major providers intend to estimate how much you have exported based on the amount generated. As far as we know most are going with a generous 50/50 estimate.

Energy you produce will flow to its nearest point of use. If there is demand within your home this will be nearest. If you produce more than you currently demand the excess will flow to its nearest point of use via your mains electricity cable. In all likelihood there will be demand from one of your neighbours and this is where the electricity will be used. The electricity flows via the grid to your neighbours."

In this way, there is no transmission loss. There are no substations or transformers to go through, which eat energy at the change over. It is another reason why the generous Feed in Tariff can be justified. For every kilowatt used by your or your neighbours, it is saving the heat equivalent of 3 kilowatts of coal in a distant power station.