How can we best use our solar generated electricity?
Posted by Cathy Debenham on 2 November 2012 at 9:34 am
Q: We have just installed PV solar panels, rated at max output of 2.25 kW. Very pleased so far (3 weeks). Careful use of daytime electricity and a woodburning stove for cooking means our energy is only costing an average of around 50p per day. (We collect waste wood to burn and we do most of our cooking on it, including hot water for drinks and washing etc). Need info about how to best utilise the solar generated electricity, preferably storing it as heat in storage heaters or as hot water. Good advice is proving hard to find, there seems to be little expertise around
A: Great to hear that you like your solar panels. How you interact with them can have a significant effect on the return that you will get from them.
The more of the solar generated electricity you can use on site, the better the return. You will get a deemed export of half of what you generate whether you export it or not. You will get just 4.5p per kWh, where you probably pay around 14-16p to import it.
So rule number one is to schedule activities that use electricity while the sun is out. These would include running a dishwasher or washing machine or doing the Hoovering.
I find it helpful to have an energy monitor, that tells me at a glance when my panels are generating more than I'm using. I use Wattson, you can read my review here, but there are others available too.
There are a variety of ways to use excess solar electricity to heat water ranging from manual, to totally automatic. The more automatic, the higher the cost. Click the link above to find out more. We will be reviewing the most popular systems on the site this month, so keep a look out in the blog if you want to read about them.
Using the electricity in storage heaters is problematic. Firstly because you need the heat in winter, when you generate significantly less heat. Secondly as your system will not generate the 3kW needed to do this. Our energy expert advises against - read why here.
If you are prepared to make a fairly hefty investment, there is a new system just launched which allows you to store excess electricity for use in the evenings. The SunBat offers enough power to cope with cooking, lighting, the TV etc.
If you have a question about anything in the above blog, please ask it in the comments section below.
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