Is all my solar electricity being exported?
Posted by Chris Rudge on 10 October 2013 at 9:22 am
Q: I suspect that all the generation from my 3.12 kW Solar photovoltaic panels is being exported as since installation almost 2 years ago my electricity bills have increased rather than reduced despite over 5,000 kWh being generated. How can I check this is the case?
A: Any power being generated by your PV system will be available for use in the premises 'at the point of generation'. This means the generated power is only available as it is being generated, otherwise it is exported. The fact that your generation meter has clocked up over 5,000kWh shows the system is sending power somewhere.
There are a couple of instances in which the power will seem not to be available due to installer error:
1) If somehow the installer has connected the PV onto the wrong side of the import meter, your bills would be unaffected though you would still be using the generated power. In theory this should not occur due to meter seals, etc but we have seen some underhand practices simply to make wiring easy for the installer. One scenario that we've seen is using the outside Meter Box to house the PV mains interface.
2) The installer has connected the PV onto another supply. For example the flat downstairs, etc. This could occur in a multi occupancy building quite easily.
Another aspect to think about is whether you have installed additional electrical devices in the house since the PV installation.
Or is could simply be, that like most other electricity companies, your supplier has been turning up the unit costs over the last few years. Certainly, a couple of years ago I was on 12p a unit. Now I'm on nearer 15p a unit with a larger standing charge too!
Note from Editor: In addition to what Chris has said, I'd like to add a bit about how active you are in using solar generated electricity. There is often an assumption that because the assumed export for the purposes of the feed-in tariff is 50%, that most people will use the other 50% at home. However, my impression is that this won't be the case for most people. We have a much smaller PV system than you (2.1kWp), and I work at home, and we try to put washing machine and dishwasher on when the sun is shining, yet we only use 35% of the electricity we generate. If you are out during the day, and don't put appliances on to run during daylight hours, then you will use less.
More information on solar PV and meters on YouGendibytes via Compfight cc
About the author: Chris Rudge is a qualified electrician who specialises in renewable energy.
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