Until recently, many CIOs didn't know how much electricity their IT equipment used, and they didn't care.

The electric bill was someone else's responsibility -- usually the head of facilities -- so they didn't track it, and they weren't motivated to reduce it. They didn't factor energy efficiency into their IT purchasing decisions, either.

Now, with a stagnating U.S. economy, CIOs need to squeeze every penny out of their IT operations, and that means choosing the most efficient servers and desktops, as well as data center power supplies and air conditioning systems.

CIOs are being hit from all sides to become environmentally savvy, not just because it sounds good but because it cuts costs, drives profitability and improves competitiveness.

We've put together a list of the Top 10 people who are pressuring CIOs to green up their IT practices.