Making power while the sun shines

It's no secret that I'm keen on self generated energy, energy prices that only go one way and my environmental footprint are things that concern me. However, environmental measures need to make financial sense as well as being something that can be painlessly incorporated into my lifestyle for them to be worthwhile. This puts me between the two camps of the "green" (some of whom are fond of telling me that I should adopt green technologies on ethical grounds without considering any ROI), and the "capitalists" who are only interested in the bottom line. I suspect that most people would be willing to consider greener technologies if my two criteria are met, without the lectures on ethics.

When I moved into my house in late 2009, I did so knowing it would be a good location for a solar PV installation. The first year was spent getting things straight after the move. By the start of 2011 I had started talking to installers about solar panels and working out if they'd be economically viable. They were, just, if I was prepared to wait 8 years for break-even. I concluded that energy prices were only going one way, and using them as a hedge against rising energy bills was enough to make me swallow hard and dust off the cheque book. After meeting with 3 possible installers it was clear that one was head and shoulders above the others and came with recommendations from happy customers I knew, the panels went up onto my roof a few months later.

It turned out I was just in time to register for the generous government FIT scheme that proved very popular. I watched with mild amusement as in the three months between accepting a quote for installation and my installation date my colleagues perception of me went from 'weird greeny' to evil capitalist' solely due to press coverage of the scheme.

Looking back did it make sense? Three years on I have recovered 40% of my initial outlay and my energy bills have reduced significantly. I still expect to reach break-even in year 8. When I was selecting my installers two colleagues from the University were just ahead of me on the curve, having just had their panels installed. One, now retired, invited me to inspect his installation and showed me a neat bit of kit he'd built that would take the excess power generated during the day while he was out and divert it to the immersion heater in the hot water tank. At the time it was a small black box covered in gaffer tape with a blinking red LED. He took this idea away, patented it and now runs Solarcache jointly with the chap who installed both our panels as a retirement business. He's not the only one to have had this idea, and a couple of companies now compete in this space. When my panels were installed his device was not available to buy, and a year later when I enquired a retrofit would have needed extra wiring to the water immersion tank which would have involved tearing up carpets and drilling holes in places I did not want them drilled. By 2013 they had a wireless version, and in March I had one of these fitted. It works splendidly and I am delighted with it. The boiler was turned off just after it was installed and I have enjoyed hot water since then at no additional cost, which is the sort of price I always like.

A couple of weeks ago my retired colleague phoned. Would I like to be a guinea pig for a new version of Solarcache that he's working on? I'd have a prototype swapped for my existing model and in return he'd like me to provide useful feedback and suggestions for improvements. I was up for that, so he came over last Sunday and swapped out my existing device. I like the new version and have sent him a few suggestions already. Without giving away his secrets the build quality of the unit is better, the new UI an improvement and there is more functionality. Hopefully this will help him in what is proving to be a competitive niche market. We also had a discussion about documentation, what he has is already good, but I may be giving him a hand with improving some aspects of that in my spare time if he wants the help.

Does it all make financial sense? Well my fuel bills are lower - usage electricity is down by ~33% from the year before they were installed. It will be interesting to see what effect the Solarcache has on the gas bill after a full 12 months. Generally I am pleased with the system and have adjusted my behaviour to run the washing machine and dishwasher on sunny days when the electricity comes from my panels and not the grid.