Will my Immersun qualify for RHI payments?
Posted by Cathy Debenham on 13 August 2013 at 10:58 am
Q: We have recently installed an Immersun to compliment our solar PV. This is using between 4 and 6 Kw hours per day to heat our water. It was simple to install and much cheaper than our solar thermal panel in our last house. Does the Immersun (or equivalent) qualify for a renewable heat incentive (RHI) payment as they do the same job?
A: The short answer to your question is no. PV switches do not qualify for RHI payments. While they are cheaper for the owner of a solar PV system, they are not cheaper in carbon terms. And the Department for Energy and Climate Change's goals for the RHI are to meet the renewables targets and carbon reduction targets.
There is an argument that while installing a PV switch is within the feed-in tariff rules, it is not in the spirit of the scheme. Everyone with solar PV is paid to export half of the electricity they generate, but if they use it to heat water they are not exporting it.
In addition, by dumping surplus solar generated electricity as heat anyone who normally heats their water using mains gas is increasing their CO2 emissions, and reducing the carbon benefits of their solar PV installation.
This is explained by the Stuart Elmes, CEO of Viridian Solar (manufacturer of solar PV and solar thermal panels) at thesolarblogger:
"The electricity we use is mostly made by burning gas and coal at a relatively low efficiency in a power station. A unit of electricity is not only worth more in pence, it also costs more in carbon dioxide emissions than a unit of gas heating.
"If a unit of electricity is exported from your home, it displaces a unit of electricity used somewhere else on the grid, and prevents the emission of 522 grams of carbon dioxide.
"If instead, a gas-heated home installs one of these switching units and heats water instead of exporting that unit of electricity, it is preventing the use of a gas boiler to provide a unit of heat, and saves only 212 grams of carbon dioxide."
He calculates that over a 25 year lifetime a typical solar PV installation that doesn't use a switching unit would save 5.5 tonnes more carbon dioxide emissions than a system with a switching unit.
On those figures, there's no way that the government is going to incentivise solar switching!
More information about solar switches and the RHI on YouGenCathy Debenham
If you have a question about anything in the above blog, please ask it in the comments section below.
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