Sad but true, the PC uses only half of the power that is supplied to it via the wall socket. Shamefully the other half gets simply wasted. Tech companies like Google and Intel plus others unfolded the Climate Savers Computing Initiative, an effort to increase energy efficiency in PCs. Their first step is to motivate PC makers and users to use more efficient power supplies and voltage regulators. According to the Initiative, these two components, working together, convert AC power from a wall socket to 12-volt DC power that a computer uses. Apparently “50 percent of the power delivered from a wall socket to a PC never actually performs any work,” says Urs Hölzle, Google fellow and senior vice president of operations. “Half the energy gets converted to heat or is dissipated in some other manner in the AC-to-DC conversion. Around 30 percent of the power delivered to the average server gets lost.”

So essentially the power in both cases is lost before a computer accomplishes any work. And when the PC remains idle even more energy is lost. By simply using better “energy-efficient components” PCs and servers can use 90% or more of the electricity that they receive. While the bigwigs crack their heads to come out with an energy-efficient, cost effective PC, I suggest we do out bit by switching off the PC when not in use. After all its our environment and energy that we are saving.
Did you know that Petrol engines have an efficiency of 30% and Diesel engine 45%.