A proposal to connect the electrical grids of Maui and Oahu with an undersea cable would save utility ratepayers on both islands an average of 6 cents a kilowatt hour over the life of the project by increasing the amount of renewable energy that could be tapped and allowing the two grids to operate more efficiently, a state officials said tonight at a state Public Utilities Commission meeting.

Although the cable would cost an estimated $700 million to construct it would result in a net savings to ratepayers of $423 million over the 30-year life of the project, state Energy Administrator Mark Glick said in a presentation at the meeting called by the PUC. About 80 people turned out for the hourlong meeting at Farrington High School.

The PUC is gathering public comment as part of its investigation into whether an undersea cable between Oahu and Maui is in the public interest. The PUC has scheduled a similar meeting on Maui on Thursday.