The patents for 31 eco-friendly technologies have been released to the public domain under a new green partnership lead by IBM.

The computer giant has teamed up with Nokia, Sony and document management firm Pitney Bowes to form the Eco-Patent Commons collective.

The group hopes to accelerate the spread of environmentally beneficial technologies, while promoting business opportunities through collaborative ventures.

"In addition to enabling new players to engage in protecting the environment, the free exchange of valuable intellectual property will accelerate work on the next level of environmental challenges," said IBM senior vice president John Kelly.

The patents are available from the web site of the World Business Council for Sustainable Development, which is supporting the project.