Tuesday, 16 August 2011

The last major eco project

The final frontier has finally been breached in terms of making Banceithin as sustainable as possible. We have always purchased our electricity from Ecotricity on an 100% green tariff, but we have also always wanted to generate a large proportion of our own energy. The cost of installing a wind turbine or solar panel array was out of our reach and, until we had completed the refurbishments, we didn’t want to risk spending our last bit of capital, but with the majority of work at Banceithin completed I started to look into micro generation again.

The UK government have introduced a tariff scheme for small producers of electricity to encourage more people to install micro generation systems. The tariff pays you a set amount for every kW hour of electricity you generate, which is index linked for 25 years. You also get a dramatically reduced leccy bill, and if you produce more energy than you use, your energy supplier will pay an addition unit rate. All in all it added up to a ‘no brainer’ - with our savings earning under 2% in any bank account, a micro scheme should return between 8-12%. With these facts in hand, we then had to choose which technology would be best suited for us. I always had a romantic notion that a wind turbine would be best for us here in Wales, but on further investigation, the cons quickly outweighed the pros.


  1. We visited a 4 kW turbine near us during a windy day, and were amazed how noisy it was, a really steady high frequency whirr.
  2. Having moving parts, a wind turbine would need more maintenance.
  3. Wind turbines, and especially their installation, are more costly than photovoltaic panels.
  4. The feed in tariff for wind turbines is less than for solar PV.
  5. You need planning permission for wind turbines, and that is a sensitive subject around here…. Solar panels below 4 kW don’t need planning permission in England and Wales.


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The main reason not going for solar initially was that we just thought it seemed ridiculous here in Wales, but these modern panels still produce even when it’s cloudy (though admittedly not as much). Maybe it’s something to do with the fact the panels are manufactured in Wales!

So it doesn’t take a genius to figure out that we plumped for the wind turbine…… no no, just joking. We went with a local company, who did our electrical work here on the cottages, for the provision and installation of 22 solar panels with a maximum capacity of 3.96 kW hours. We’ve had them installed on the wood shed which is south facing, and the contractor increased the angle of elevation of the panels from the paltry 6 degrees of the shed roof, to 15 degrees, which increases the performance of the panels, and allows the self cleaning coating to work.


The 22 panels on our wood shed.


The ‘Sunny Boy’ inverter (no really, that's what the manufacturer calls it, not us!) converts the energy created by the panels into usable 240v AC power fed back to the house, with excess being sent back to the national grid. Unfortunately the Sunny Boy has a digital display which tells you how much power you are creating at that moment, and how much you’ve created in that day. This means I am continually ‘popping’ up the shed to check on how much we have generated and reporting back to 'er indoors. I have been very impressed with the performance so far. We have an average daily usage of 14.5 kW hours, and with the panels in for a couple of weeks now, we have been creating anything from 7 kW hours to 25 kW hours. The 7 kW hours was produced on a dreadful rainy day here, but that was still virtually half of our daily usage….though it is August…..

One of the the best bits about the install is that the contractor has installed lights and some power points to the shed. My work bench now is fully lit and will allow tinkering long into the night!

1 comment:

Andrew P. said...

Looks great and a fantastic use of the flat roof. It would be great to see a chart of your first month's production.

In defence of wind I'd say there are plenty of very quiet small (and big !) turbines with a lot of noise coming from poor maintenance rather than design.

The energy yield ratio of wind projects (the amount of energy produced in proportion to the amount of energy used in production) is around 80 compared to 4 for solar (7 in a sunny country) - see David Mackay's excellent "Sustainable Energy - without the hot air" - free on his website - for the figures. A small turbine in your part of Wales would probably be a more efficient way of producing electricity than solar, particularly in winter, something government didn't really consider with the feed-in-tariff regime

Great to hear your barn is now fully wired - does this mean a heated owl box over the winter ? :-)