Supercomputers have been around since 1920, when IBM built custom tabulators for Columbia University. Nowadays they do just about everything from predicting weather to playing the stock market.
High-performance computing has (obviously) always been performance oriented. However, environmentalism is sneaking in here as well (some say the hippies are driving it), as supercomputing centers use vast amounts of energy. And, since peak performance is rarely attained, some of this energy consumption results in little or no performance gain. The problem is beginning to be studied; there is even a conference devoted expressly to this issue. There is also a site called Green 500 that ranks all of the supercomputers in the world by how ecofriendly they are. Like others, they are trying to determine the best way to do this, they have an RFC if you would like to contribute.