The state is taking the first step in the development process for an undersea electrical cable that could someday transmit energy generated by windfarms on Moloka'i and Lana'i to O'ahu homes and businesses.

The state Department of Business, Economic Development and Tourism said it has awarded a $1.5 million contract to the University of Hawai'i for mapping of the ocean floor between Honolulu and Maui County with the hope of identifying the best possible route for a cable.

"The cable is a major, significant enabler of our clean energy future," said Ted Peck, state energy program administrator.

"It entails the installation of a high-voltage interisland system to integrate the electrical systems of the islands of O'ahu, Maui, Moloka'i and Lana'i," Peck said.

The state last year announced the cable as part of its Hawai'i Clean Energy Initiative, designed to cut the state's dependence on foreign oil for most of its energy needs. Gov. Linda Lingle's administration's plans call for 70 percent of the state's energy to come from renewable resources by 2030.

Two 200-megawatt windfarms are being planned for Moloka'i and Lana'i, with the power being sent via the cable to O'ahu. The 400 megawatts could provide up to one third of Honolulu's power needs.

"It's really a project investing in our future as a state," said Peck, who said rough cost estimates for a cable are between $500 million and $2 billion.

"We need to get off the volatility and uncertainty of the supply of petroleum."

DBEDT has contracted with the UH School of Ocean and Earth Science and Technology to conduct a survey that includes determining depths, ocean floor composition and photographing possible routes.

Peck said a technical review committee has met several times and that much work remains to be done, including an environmental impact statement, before the project becomes a reality.

He said there are concerns about the endeavor, including how to mitigate any damage to marine life. The possible routes could go through whale sanctuaries.

Robert Harris, director of the Sierra Club Hawaii Chapter, said the whale issue will have to be addressed in the EIS.

But he said the Sierra Club has not decided on a position on the cable, but that he hopes the state also is looking at other alternatives, including incentives for developing smaller, more diverse sources of energy on O'ahu, along with improvements to its grid.

"It's a lot of money," Harris said. "What DBEDT needs to do is a pretty detailed analysis of if it's the best investment of dollars."