Our PV cells installed on the roof

Our Photo-Voltaic cells

At our home we use about 5 KWhours per day. The mains price averages at 0.14 £/KWh so it cost us £0.70/day or £355 per year. I had been sceptical about PV electrical energy. Using our own prices, our 1.8 KW installation with 10 panels of total area 12.8 m² cost £9000 and its estimated yield is 1594 KWh/year. The pay-back time comes out at (9000/0.14)/1594 or 40.3 years, hardly worth it.

However the government has its green targets and energy supply worries and in April 2010 decided to pay home generators a "feed in" tariff of 0.413 £/KWh. This is three times the normal price, and means that the pay back time is similarly reduced to a very reasonable 13.7 years. Putting it another way the income of £1593x0.413 is an 8% tax-free return on our investment.

Following good experiences from our friends we went to The Green Electrician who did an excellent and trouble-free installation for us in just three days finsishing on 15/6/10. They even gave us a bottle of champagne for being their 100th customer.

It has been very trouble free. Indeed sitting there quietly on the roof it is out of site and out of mind.

An update on 12/4/23. The system continues to work fine. What is good news is that our £9000 costs have now all been repaid in about the pay-back time predicted above.