The state has identified four potential routes for an undersea electrical cable that could deliver energy generated by wind farms on Molokai and Lanai to homes and businesses on Oahu.
The state Department of Business, Economic Development and Tourism also said it has narrowed its estimates for the costs of the undersea cable to $800 million and $1 billion.
The state previously said the cable's cost could range from between $500 million and $2 billion.
A $1.5 million report conducted for DBEDT by the University of Hawaii concluded that the undersea power cable project is feasible, despite environmental and engineering challenges.
"This is a huge first step," said Josh Strickler, facilitator of DBEDT's renewable energy programs. "Before we didn't know this was physically possible."
As part of the Hawaii Clean Energy Initiative, Gov. Linda Lingle's administration last year unveiled plans to build the cable connecting Oahu to two 200-megawatt wind farms planned for Molokai and Lanai.
The 400 megawatts could provide up to one-third of Honolulu's power needs and would play a key role in the Lingle administration's plan to reduce the state's dependence on fossil fuels.
The cable study, conducted by the UH School of Ocean and Earth Science and Technology, relied on extensive ocean mapping and geological studies to come up with its recommendations for the four potential cable routes.
The routes included a Lanai to Pearl Harbor route; a cable connecting Molokai, Lanai and Maui; an Oahu, Molokai and Lanai cable; and a Kaneohe to Molokai line.
Initially, DBEDT and UH researchers looked at nine potential courses but narrowed the choices based on distance, cost, proximity to existing undersea telecommunications cables and potential impact on wildlife and the environment.
Two of the routes run close to whale sanctuaries.
Strickler said the state plans to use the cable report as a basis to develop an environmental impact statement for the project. Many of the impacts on wildlife and the environment will be addressed by an EIS.
Strickler added that the state recently narrowed its cost estimates to the $800 million to $1 billion range after studying other underwater power cables and by talking to a number of cable manufacturers.
"This project is definitely doable," he said.