Solar PV installation, Harpenden, Herts. 2.22kWp system

Having been interested in domestic energy generation for several years, we’ve been watching developments in the various technologies over this time. The wind technologies for the domestic market never lived up to expectations. Our hot water is obtained through a gas combi boiler so solar hot water wouldn’t be financially viable. As for PV, the recent government FiT scheme suddenly made it very attractive. So we started looking into it. We did our research on systems, manufacturers, technologies, searched websites for indicative prices and contacted several installation companies for a chat.

At this point I must warn prospective PV clients about the selling techniques some companies employ. As knowledge grows about domestic PV and the government’s incentives, companies are springing up at a very swift rate to jump on the band wagon. There’s companies sending out reps with little or no knowledge of the technicals, and operating the ‘double glazing’ sales/marketing techniques whereby the price drops 40% over the course of their visit! If you come across one of these techniques, DON’T sign up!! The reputable companies will provide an indicative quote by phone or email and if you’re interested in taking it further, they’ll send out a technical bod for a site visit. The site visit will confirm your property’s orientation, the roof construction, the cable routing, the siting of the electronic boxes, and confirm (or modify) the indicative figures of generation (units and cost benefits) that you’ll have received in your provisional quote. It’s worth bearing in mind that any indicative figures given to you should have been based on the government’s SAP figures, which are generally conservative.

The company we chose was Spirit Solar, based in Reading. They were professional, thorough, knowledgeable and above all fun to deal with. They shared the ‘buzz’ and excitement of ‘green’ energy, which made the whole experience even more pleasurable. The installation went without a hitch and we were generating juice by 4pm on the second day. We do, however, live in a bungalow which made the install relatively easy. There was no need for extra scaffolding and we had given thought ourselves to the cable routing to make things easier.

We’re now one week on from commissioning and all the facts and figures we worked out (and those we were quoted in quotes etc) appear to be on target as expected. And we can’t stop watching the Sunny Beam wireless generation meter!

We have 12 x 185kWp Yingli poly panels with a SMA Sunny Boy 2500 inverter, providing a 2.22kWp system. We face due south-west with no shading. The expected annual output is around 1,750kW – about half of our annual electricity usage. System cost was £10,500.

We anticipate an annual return of around £900 – a combination of Feed-in, export units and the saving on our electricity bill. Guaranteed for the next 25 years, and tax-free!

Steve Bryant. Aug 2010.