I have to admit that things like this make me laugh like a drain :
It has become the home improvement of choice for the environmentally aware, but erecting a wind turbine on the side of your house could create more carbon dioxide than it actually saves, a study into their performance will reveal today.
Clearly, I have a slightly warped sense of humour.
The point is though that the amount of electricity generated, and thus the emissions "saved", is too small. It doesn't make up for the emissions involved in the manufacture of the machinery in the first place. Thus, outside places like Wick (I knew the place had to be good for something), having such a windmill increases, rather than reduces, total emissions. Clearly not what we want to happen at all.
Now of course, given that David Cameron is the only man in the Kingdom known to actually have one, the total effect isn't all that large. However, there's a deeper point at issue here. If we're going to try to save emissions by using this or that technology, then we've got to make sure that we actually do the cost benefit analysis. For example, we are repeatedly told that nuclear has, over the whole fuel cycle, CO 2 emissions: something which is absolutely true. What does not follow is that we shouldn't use nuclear to reduce emissions. For such emissions are lower than those from coal and gas (as should be obvious). More than that though, they're actually about the same as those from onshore wind power, and less than half those from solar PV. To say that we shouldn't use nuclear because of such emissions is also to say that we shouldn't use the other two for the same reason: not quite what those drawing our attention to the CO2 and nuclear issue really want us to conclude.