DatacenterDynamics and The Green Grid identified the data centers in Japan that have made the most improvements in relation to efficiency as part of the Most Improved Data Center Energy Efficiency Award in Japan this week.

Hitachi took out the Grand Prix award after receiving the highest marks in the competition, judged by members of The Green Grid, DatacenterDynamics, the Green IT Promotion Council and the Japan Data Center Council.

Over a five-year period Hitachi achieved a 50% reduction in energy consumption in its data centers compared to levels seen in the 2007 financial year.

Monitoring also worked well for Fujitsu, which won the performance award based on its view on data energy use trends and the formation of energy-saving workgroups, combing engineering with innovation.

It improved its PUE by using new air conditioning technology and made use of PUE calculations and graphs to visualize the state of its energy consumption.

Colocation and hosting data center company IDC Frontier put the focus on modular data centers when it received the Special Award for bringing down its PUE using large external air conditioners.

It also uses cold/heat separation techniques, blast friction minimization and says its choice of the modular data center is also down to its drive for energy efficiency.

The winners were marked on their efforts for monitoring and measurement and analysis of the data center and actions taken to turn findings into physical changes which lower PUE.

Japan Technical Work Group of the Green Grid chairman Eiji Taguchi said this year's award entries came from a number of areas, including the IT, telecommunications, financial and manufacturing sectors.

"The candidate companies, recognizing that green initiatives are crucial for business sustainability, are committed to contributing to society by addressing environmental issues throughout their organizations," Taguchi said.