9th September 2014
Photovoltaic panels are one of life's mysteries. I helped shift them up the scaffold today before their installation on our south-facing roof. They seem so insubstantial - little more than a sheet of plastic stretched taught over a rectangular frame - and are easy for one person to handle. Three of us had them on the roof in ten minutes. And there they will sit for the rest of our lives, doing seemingly nothing yet churning out most of the power we need for our (ultra-low energy) all-electric house. Genius.
Our panels are supplied by ICB, who also supplied the Alwitra roofing membrane that Steve and Ashton have been installing. They will also be making the cappings for our parapets. They are basically a roofing company with knobs on. Or, rather, they understand that modern roofs tend to have knobs on, such as solar panels, and so people like me appreciate an integrated approach. Happily, they also supply the most efficient PV panels on the market, manufactured by Sunpower, so we can get the very best output from out limited unshaded roof space.
A key issue for any solar panel installation is maintaining the integrity of the weather-proofing of the roof. So: Ashton fixed metal bars wrapped in the membrane onto the existing membrane, drilling through to the wooden deck that I laid last week. Then Steve came behind him and welded the membrane pieces together and covered up the screws so that no rainwater can get into the supports. Then Andy and Al from ICB fixed the frame for the solar panels onto these protected supports. Then we heaved the solar panels up the scaff. Then Andy and Al fitted the panels in less than 60 minutes. If they hadn't been waiting around for 24 hours for a repeatedly delayed delivery, it would have been incredibly efficient.
So there we have it: a 3.6kW (peak) system that will hopefully generate around 2,600 kiloWatt-hours of electricity every year. Not, of course, when we particularly need it. That's always the problem with solar electric: when the sun is shining at its brightest in the middle of summer, I'll be lying on our chamomile lawn with a cold beer and the panels will be producing far more power than is needed to chill the remaining beers in the fridge. So we will be exporting to the grid and running our neighbours' fridges. That's what the grid's for, after all. We'll buy it back in the winter when the sun doesn't shine but many steam puddings are required.
Anyway, cheers! A good day in wonderfully warm late summer sunshine. Perfect weather for having fun up on the roof.