See, now you're asking question, that's a good thing.
He's purchasing carbon offsets. This means that he's hired a service to count his CO2 output, and they're charging him money based on his consumption. They then put this money into subsidising electrical purchases elsewhere in the country, so that that green energy is being bought by other people, instead of coal-fired electricity. (in addition to other things, like green research and carbon sequestering).
The sum total of this is that (after factoring in the money he spends) his family produces less total CO2 than an average family. If he wasn't purchasing the offsets, then people wouldn't be using the Texan windfarms (for example) as much as they are, because they're not priced properly yet.
I think that you should include the following in your OP, so that people can form a more reasoned opinion. This will change the nature of the OP into one that inspires debate. As well, since many people only read the OP, they're not getting the information that Jolly Roger already included. You're not currently bringing forward the knowledge that the $30,000 is green power. Keep in mind, too, that this $30,000 is being paid at a higher rate, because he's capturing the cost of the CO2 production.