£100 – or less – to save the planet

The purpose of this blog is for me to record the ways I've found to reduce my carbon footprint. It'll probably contain other environmental matters as well. My guiding principle is that I record the things I do, so that others can, if they wish, do the same. In order to assist others in the decision making process, I will provide, where possible, illustrative costs; I cannot guarantee that the costs that I incur are the costs that you will, but I can at least record my own costs (and savings) accurately.
So why the title? Well, I think the Copenhagen summit was mostly a waste of time. Yes I'm sure some good things will come out of it, but I think that we may find ourselves saying "too little, too late". Anyway, I discovered today that I paid approximately £360 for electricity in 2009. I also discovered that I could switch to a 100% renewable tariff which would cost about £460. So for an extra £100, I can have completely green electricity. I think that's worth paying.
I've also signed up to the 10:10 campaign (http://www.1010uk.org). This means I've promised to cut my carbon emissions by 10% in 2010. Of course, domestic electricity isn't the only source of carbon, but it's an excellent start. And of course if I can reduce my electricity consumption, it won't cost me £100 – it'll be less than that.