By: Phil Worthington
Just over a year ago we had a 4kW solar system consisting of 17 solar panels installed at our family home in Cheshire. This is a brief review of how it's working out for us so far.
Since we live in an old farmhouse (over 250 years old) with a heavy stone roof, we decided against a rooftop installation. Fortunately we have a pretty big garden/paddock so setting aside a small area for ground mounted solar panels wasn't a problem. It did mean a bit of a cost increase for the ground mounting trays and burying a long cable to the house, but overall the system came in at under £8000 for 17x265W panels with power optimisers.
The system has been running without any problems since the end of January 2016. To the end of February 2017 it has generated 3.6MWh of electricity, which is in very close agreement with a www.powermarket.net estimate of 3.1MWh per year for a system of this size in this location, although the cost estimate of installing a similar system now is much lower due to price falls over the last year.
We’ve cut our electricity usage by about half, but unfortunately a lot of our generation is being exported to the grid rather than used by us. We are getting better at putting the washing machine and dishwasher on during daylight hours to make more use of it and minimize our use of electricity from the grid. That’s obviously saving us some money (approx. £300/year) at the moment but as with most UK households, we’ve just been informed that our electricity price is about to rise by 10%, so the financial benefits are likely to get substantially bigger over the 25+ year lifetime of our system.
If we had battery storage the solar panels would more than cover our current electricity usage except during the winter months, with plenty to spare for heating water in the summer. Our house isn’t on mains gas so we have to use an oil boiler for heating and hot water, but during the summer we’ve already cut down our oil usage a bit. Peak generation was around 400kWh in June, July and August 2016, or around 13kWh per day, which is far higher than our usage. With storage, we’d expect to be pretty much self-sufficient for electricity from March-October, and get a useful contribution to our usage outside those months.
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