Hoku Scientific Inc. said yesterday it has signed agreements with the state Department of Transportation to install photovoltaic power systems at four Hawaii airports. Collectively, it is the largest single customer commitment for photovoltaic installation that Hoku has ever received.

The DOT will buy up to an aggregate of 779 kilowatts of photovoltaic power from several systems to be installed, owned and operated by Hoku Scientific subsidiary Hoku Solar Inc.

The Kapolei-based alternative energy provider will install the systems at Lihue Airport, Kahului Airport, Kona International Airport at Keahole and Hilo International Airport this year, along with several other DOT buildings. The largest outlay will be at Lihue, with a total estimated system size of 336 kilowatts, or 43 percent of the total, followed by Kahului at 143 kilowatts, Hilo at 112 kilowatts and Kona at 60 kilowatts. Two Kauai harbors and highways rooftops account for the remaining 128 kilowatts.

The installations are subject to Hoku's ability to obtain third-party financing for the purchase and construction of the systems.

“;Through this initiative and many others, the state of Hawaii continues to demonstrate real leadership on issues surrounding renewable energy and climate change,”; Hoku Chairman and Chief Executive Dustin Shindo said.

The DOT will buy the electricity generated by Hoku at a predetermined rate over a contract period of 20 years. The projects will contribute to the state's focus on renewable energy. In 2006, Hawaii passed a law that calls for one-fifth of the state's energy to come from renewable sources by 2020. The project could produce enough electricity in 20 years to power nearly 1,900 homes for one year and offset up to 15,000 tons of carbon dioxide emissions over the lifetime of the systems.

“;This is an exemplary public-private partnership that will bring clean, solar power to many of our state's public facilities, with minimal upfront investment,”; DOT director Brennon Morioka said. “;Now, more than ever before, the state must seek every opportunity to integrate renewable power and energy conservation into public operations.”;

DOT spokeswoman Tammy Mori said funds to purchase the power from Hoku will come from the operation, maintenance and electricity budgets of the airports, which are funded by the state DOT. The power generated by the photovoltaic systems is expected to be 3 cents cheaper per kilowatt than current power rates.