What about storing off-peak night-time electricity as well?

The most common form of cheaper night-time electricity is known as Economy 7, but at present (April 2022) many supplies have removed these tariffs.   Octopus and Ovo also have interesting tariffs intended for owners of electric vehicles. For example, the Octopus Go tariff is currently 7.5p per kWh for the four hours between 00:30 and 04:30. If you have a battery with capacity at least as large as your use on a winter’s day, you could be able to use very little peak electricity any season.  Using our example, we assume that we use 1,020kWh direct from our solar panels [...]

By |2022-05-23T14:03:28+01:00May 23rd, 2022||

What if I add a battery to store excess solar electricity?

Experience suggests that with a 10kWh battery you may be able to use about 70% of the 3,400kWh you produce even if you use only 30% directly, i.e. an extra 1,360kWh. Then, your battery will save you 1,360kWh at 30p, i.e. £408 pa. Assuming the battery costs £5,000 the payback time is a bit over 12 years, longer than the currently expected lifetime of the battery. 

By |2022-05-23T14:02:39+01:00May 23rd, 2022||

What is the payback on solar panels producing 3,400kWh pa without Smart Export Guarantee (SEG)?

Let’s assume that you pay 30p per kWh for grid electricity (typical domestic electricity unit price from April 2022) and use 30% of what your panels produce, i.e. about 1,020kWh. Then you will save just over £300 pa and your £6,000 will take 20 years to pay off. If you use 45% the payback period comes down to 15 years and for 60% it’s 10 years. Quotes from some installers will make assumptions about inflation rates and will get smaller payback periods. You have to make your own judgement on how much weight to give to this but there seems [...]

By |2022-05-23T14:00:52+01:00May 23rd, 2022||
Go to Top