It is well-known that computers and power saving don’t go together.
Today microprocessors waste lots of power (for example due to the leakage current). Moreover, power is proportional to frequency, and the number of transistors per unit of area is always increasing. As a matter of fact, current chip mounted on normal PC need some cooling system. Usually, a fan mounted on the chip is enough. However, the trend is increasing and for next generation chips and for supercomputers engineers are experimenting with liquid-cooling systems.
Even with liquid, the amount of power consumed continues to increase. In fact, you should also account for the power needed to run the cooling system! You need a pump, and then a fast way to cool the liquid.
I heard that when Google wants to build a new data center, they look for nice locations near a river or lake, and use the water as cooling liquid.
Engineers at IBM and researchers at ETH are doing research on how to liquid-cool a microprocessor since many years. Now they are putting their research into practice: they plan to build Aquasar, a supercomputer based with a new water-cooling system. Also, the heat will be injected in the ETH campus’ heating system.
It’s a 10 Teraflops supercomputer, but they plan to save up to 30 Tons of CO2 per year. Not bad!