IBM, long known for making many of the fastest supercomputers in the world, has another supercomputer accolade: It dominates the Green500 supercomputer list, with a whopping 18 of the world's greenest 20 supercomputers.

The list is put together by The Green500 List, and is meant to complement the well-known TOP500 list of the world's most powerful supercomputers.

The Green500 List was put together to combat what it sees as unnecessary supercomputer energy waste. The site notes:

For decades now, the notion of "performance" has been synonymous with "speed" (as measured in FLOPS, short for floating-point operations per second). This particular focus has led to the emergence of supercomputers that consume egregious amounts of electrical power and produce so much heat that extravagant cooling facilities must be constructed to ensure proper operation. In addition, the emphasis on speed as the performance metric has caused other performance metrics to be largely ignored, e.g., reliability, availability, and usability. As a consequence, all of the above has led to an extraordinary increase in the total cost of ownership (TCO) of a supercomputer.

The Green500 List instead uses a green set of standards to gauge performance metrics. Here's its explanation:

Despite the importance of the TOP500 list, we argue that the list makes it much more difficult for the high-end computing community to focus on performance metrics other than speed. Therefore, to raise awareness to other performance metrics of interest, e.g., performance per watt and energy efficiency for improved reliability, we propose a complementary list to the TOP500 - the Green500 list.

IBM absolutely dominates the list. According to the list, the world's most efficient supercomputer is at the Interdisciplinary Centre for Mathematical and Computational Modeling, University of Warsaw. It's based on an IBM BladeCenter QS22 and produces more than 536 Mflops (millions of floating point operations per second) per watt of energy.

A full 17 of the remaining 19 greenest supercomputers use IBM technology. And IBM technology powers a total of 57 of the top 100. They perform a wide variety of tasksing, including those related to astronomy, climate prediction and pharmaceutical research.

The list shows that being green can be synonomous with being powerful, because the world's fastest supercomputer is also rated the world's fourth most energy efficient. It's the IBM supercomputer at Los Alamos National Laboratories, and is capable of over 444 Mflops per watt of energy.

Making supercomputers green is no mere demonstration project; it's a way for those that run them to save money. And it also points the way towards energy savings in data centers around the world. David Turek, vice president, deep computing, IBM, had this to say in a statement about supercomputers and the bottom line:

"Modern supercomputers can no longer focus only on raw performance. To be commercially viable these systems most also be energy efficient."