"How long will it be before we see activists demonstrating outside datacentres or company headquarters about the carbon emissions produced by a company? In some organisations, over 50 per cent of the IT budget is spent on energy consumption associated with their ICT function. CIOs should really be investigating what carbon emissions their organisation is producing, and also be up-to-date with what legislation may affect them, such as the UK's Climate Change Act 2008. They should be setting themselves targets for lowering their organisation's carbon footprint."

So says Mark O'Neill in the BCS press release touting his book Green IT for Sustainable Business Practice: An ISEB Foundation Guide.I'm guessing that the answer to his initial question is 'never' although it's certainly true that datacentres chew through electricity. However, arguments over green IT still founder on one fundamental disconnect: the lack of a valid comparison supllying the true environmental cost of alternatives to automating through bits and bytes.

For example, let's say a well-known supermarket's server rooms for its dotcom operation are gas-guzzling pigs full of ancient 486-based and first-generation Pentium boxes cooled by a leaf blower using a plug the size of the Isle of Man.  Then add the cost of all this company's vans schlepping through the residential streets of Cheam, Penge, Westward Ho! and Pity Me, Northumberland. The valid ecological comparison is with what would have happened if X number of shoppers had taken to their cars and the environmental cost of maintaining shops, an extended supply chain and so on.

Similarly, just because an online bookseller chooses to power its website using a petrol-driven VAX, you would have to compare that to price to dear old Mother Earth with a high-street retail outlet chunking through light, heating and air-conditioning in every urban conurbation that this great country has to offer from the idylls of Cornwall to the pretty Kent coast and whatever the northernmost parts of Scotland look like.

My comparisons are even more ridiculous of course because of another factor that is conveniently ignored by those who seek to create headline-wresting issues where they don't quite belong. And that is that only a really, really stupid company would not pursue ways to keep their datacentres energy-efficient. Famously, the cost of power to run a server will be exceeded by the cost of juice to power it over its useful lifespan, so even if Evil Corp. is running a load of old kit then that will hurt it in terms of performance, ability to virtualise, energy bills, space, cost and any other reasonable metric out there. Everybody knows that there is a direct correlation between doing the right thing and saving money.

OK, so there will be some exceptions. Very risk-averse companies may stay on an old 'steady Eddie' piece of hardware because of legacy issues or because they have other fish to fry (possibly using the motherboard as a grill pan). But these hold-outs will move eventually because, in this case at least, market forces compel them to shift.

Green IT is a very valid debating point but let's not compares apples with basketballs. A good datacentre is an energy-efficient datacentre and those CIOs who seek to be good citizens as well as responsible operators get double bubble by making commonsense technology decisions.