WORRYING about the environment is trendy again, with everyone having house parties to watch the film adaptation of Al Gore's Powerpoint presentation, An Inconvenient Truth.

We're all talking about SUVs and biofuels, but are we even considering what our digital lifestyles are costing us, energy-wise?

There's a lot of talk about investing in IT via schools and getting more people to do science and technology courses in college, but what about the infrastructure for IT? Even if we sort out the broadband infrastructure so people can avoid the traffic and telecommute, even if we put a computer in every home and classroom, will we have the power for our technology needs?

We hear about the need for switching off those lights and turning the heating down by two degrees for the sake of our energy bills, yet we are bringing more and more powerful computing devices into our homes, and via broadband connections, we connect to Irish data centres that use more power than whole towns to serve our website needs.

The average processing power of a computer has increased drastically. Moore's law talks about computers doubling in processing speed every 18months but people do not consider that the power usage also increases along a similar line. It is not uncommon now to see home computers with power supplies going to 750W, the same power output of some microwave ovens.

Imagine the microwave on all day long. Many homes now have a second and even a third computer. Throw in Xbox 360s and Playstation 3s and the power needs of the average home are starting to ramp up.

With more desktop applications also being available online, such as Google Mail and online competitors to Microsoft Office, more data centres will be needed to host these sites. It is rumoured that Microsoft is building a data centre in Dublin which, instead of being measured in size, will be measured in energy consumption. This data centre is estimated to be a 26MW facility.

Web naysayer Nicholas Carr did a back-of-envelope calculation and concluded that virtual world Second Life uses up nearly as much energy for virtual avatars than the real humans do themselves. Second Life needs over 4,000 servers running constantly to keep people's virtual persona running.

In the United States, one of the criteria both Google and Microsoft use for planning new facilities is their distance from power stations. In North Carolina, Google is building a new facility right next to a new power station so it can tap directly into it.

The amount of data we create increases daily and a lot of it is finding itself online, stored on various web services. This needs to be stored somewhere and more and more it is stored on servers in data centres.

While the cost of storage hardware plummets, the running cost of data centres grows due to energy costs.

Dan King, general manager of Digiweb Hosting, recently highlighted the power needs of a modern data centre, where some servers use vast amounts of energy to work.

"Some server configurations will use up to 25KW in a single cabinet, that's about as much electricity as a small road of houses and near-impossible to power or cool, even in data centres, without massive supporting infrastructure.

Additionally, the increasing miniaturisation of servers, especially bladeservers, is putting far more processing power into smaller spaces, but using far more power per rack than ever before."

The CIX data centre in Cork is one that has been working very hard to reduce energy usage. CIX representative Tom Raftery noted "because bandwidth costs in Cork are up to three times more expensive than Dublin, we've had to look at other ways of reducing costs to stay competitive. One of those areas has been energy consumption".

CIX is using new air-conditioning technology as well as looking into generating its own power using plant oil-powered generators and other alternative energy generation to supplement existing power sources. CIX is also highlighting the energy costs of every server when it bills a customer, as a means of encouraging people to use more efficient servers.

While there finally seem to be more options for more fuelefficient cars, and we are encouraged to insulate our homes, there is nothing so far about the energy needs for going online and using computers. If Ireland wants to be a top 20 knowledge economy, it will need to have a proper infrastructure to supply the soaring electricity needs of the Googles and the Microsofts. Will we one day see bills with energy charges for using the net, like in the old days when we were charged per minute to dial up?