Tokyo Electric Power Co. is contemplating a joint venture with Sony Corp. and several other major firms to use wind and solar energy to generate electricity, Tepco officials said Wednesday.

The participating firms will negotiate the details of the project by the end of May and aim to set up the venture sometime this fall, the officials said.

In additon to Sony, Hokkaido Electric Power Co., Tohoku Electric Power Co. and Mitsui & Co. are considering joining the project.

The venture would build solar- and wind-powered generators and sell the electricity they produce to nearby utilities.

The project would also involve having a third-party institution issue certificates that attest to the promotion of environment-friendly energy sources by the venture’s corporate backers, the officials said.

Tepco, Sony and the other would-be participants hope to convert those certificates into marketable securities, while obtaining the authority to deal in the rights to discharge carbon dioxide into the air, they said.

Those dealing rights could be obtained if the global community were to lay down rules for such transactions, they added.

Amid growing environmental concerns, Japanese companies are expected to face greater demand to cut their carbon dioxide emissions.

Earlier this week, the government resumed, after a 10-year interim, discussions on overhauling its long-term energy policy, including ways to further promote the use of clean energy.

At the moment, the high cost of clean power remains an obstacle in promoting its greater use. The cost of electricity generated by tapping wind energy is roughly 2.5 times as high as that using thermal power.