Forum home The potting shed

Greenhouse + solar power

kevkeelykevkeely Posts: 3
edited November 2021 in The potting shed
I have a 10 X 8 greenhouse in my back garden.
I also have a 4 X 250 watt solar array on my roof.  New build.
We never registered the panels to the national grid. Been wasted for 3 years.....
Is there any way I can use this wasted power in the greenhouse?  Grow lights? Heating?
Would the cost of energy storage ( batteries) and grow lights not be feasible?



  • raisingirlraisingirl Posts: 6,428
    Is there a reason you haven't grid-tied them?
    “Light thinks it travels faster than anything but it is wrong. No matter how fast light travels, it finds the darkness has always got there first” 
  • Bit of a mixture.  Rented out for a while.   Plus the paperwork was o ballache.  Plus the revenue went down.  So can't be bothered for a few pounds.   Would be happier to use the energy in my gardening 😉
  • I'm slightly confused - do you have an inverter? What are the panels currently connected to?
  • Currently connected to the national grid.  But we didn't register them.  So they are generating power, just don't get paid for the energy.  If there is an inverter, don't know if it's usable for DC?  Would maybe need a different one for DC?
  • steephillsteephill Posts: 2,634
    One use might be to get hold of an old night storage radiator and feed that from your panels to create a frost free greenhouse. You would probably need to replace the heating coils with a sealed alternative like those used in propagators for soil warming.
  • StephenSouthwestStephenSouthwest Posts: 440
    edited November 2021
    So I'm guessing you're using some of the energy and thinking what to do with the rest, which is currently being used by the grid, but you're not being paid for it.
    I'm thinking that if you have MSC certification, you could sell it to Octopus on Agile Outgoing, though if I remember rightly, you would need to have them as a supplier. This independent website gives some info on that (and worth using their referral link if you decide to go down that route):
    Or if you have an immersion heater, you could install a diverter to automatically heat your hot water from the excess solar, or to power a night storage heater, either in the house or the greenhouse. The diverters are not cheap however - eddi is the one we use which works well.
    House battery systems can be quite expensive, in the thousands generally.
    I can't help thinking that you're currently supplying electricity to your home and to the grid - none of it is being wasted, and it sounds like you're thinking of diverting it to the greenhouse without that being driven by a need for electricity in the greenhouse - one perspective could be that this would be more wasteful!
    Another possibility is to consider using the excess solar to drive an ASHP - this would turn each kW you generate into something like 3 or 4 kW of heat. Not cheap but there are grants I think.
    ...or if you're ever thinking of replacing a car, look for an BEV to use the solar excess...

    Your inverter is turning the DC generated by the solar into AC for the house system. Technically it's possible to use the solar DC to directly charge batteries, but that's way outside my experience.

Sign In or Register to comment.