Hawaii State Department of Transportation to Purchase Clean Solar Energy From Hoku Solar

Market Wire, October, 2008

Hoku Solar, Inc., a wholly owned subsidiary of Hoku Scientific, Inc. (NASDAQ: HOKU) has been selected to design, engineer and install photovoltaic (PV) power systems at airports across the state of Hawaii. Today, Hoku Solar and the Hawaii State Department of Transportation (DOT) entered a series of agreements by which the DOT will purchase solar electricity generated by up to an aggregate of 779 kilowatts of photovoltaic (PV) power from several systems to be installed, owned and operated by Hoku Solar.

Hoku Solar plans to install the PV power systems at multiple DOT properties including Lihue Airport, Kahului Airport, Kona International Airport at Keahole and Hilo International Airport beginning in 2008. Subject to final system design, the projects are expected to total up to 779 kilowatts in aggregate. DOT will buy the electricity generated by Hoku Solar or its affiliate, who will own and operate each system, and who will sell the electricity generated by the PV power systems to DOT at a predetermined rate over a contract period of 20 years.

The projects will contribute directly to the state of Hawaii's demonstrated focus on energy savings and renewable energy strategies, as outlined in recent legislation. The initiative also advances the state's continued leadership in reducing greenhouse gas emissions. A project totaling 779 kilowatts of PV could produce enough electricity in 20 years to power nearly 1,900 homes for a year, and is expected to offset up to 15,000 tons of carbon dioxide emissions over the lifetime of the systems.

"Hoku is proud to have been selected to partner with the Hawaii State Department of Transportation on this effort," said Dustin Shindo, chairman and chief executive officer of Hoku Scientific. "Through this initiative and many others, the state of Hawaii continues to demonstrate real leadership on issues surrounding renewable energy and climate change."

"This is an exemplary public-private partnership that will bring clean, solar power to many of our state's public facilities, with minimal up-front investment," said Brennon Morioka, director of the Hawaii State Department of Transportation. "Now, more than ever before, the state must seek every opportunity to integrate renewable power and energy conservation into public operations. Power purchase agreements like these not only represent thoughtful stewardship of taxpayer dollars, but they provide important, incremental relief to the very real dangers of global climate change."

Hoku Solar plans to complete the installation of the systems in 2008, subject to its ability to obtain third party financing for the procurement and construction of the PV systems.

About Hoku Scientific, Inc.

Hoku Scientific (NASDAQ: HOKU) is a diversified clean energy technologies company with three business units: Hoku Materials, Hoku Solar and Hoku Fuel Cells. Hoku Materials plans to manufacture, market, and sell polysilicon for the solar market from its plant currently under construction in Pocatello, Idaho. Hoku Solar markets, sells, and installs turnkey photovoltaic systems in Hawaii. Hoku Fuel Cells has developed proprietary fuel cell membranes and membrane electrode assemblies for stationary and automotive proton exchange membrane fuel cells. For more information visit www.hokuscientific.com .

About the State of Hawaii Department of Transportation, Airports Division (DOTA)

DOTA is a division within the Department of Transportation in the State of Hawaii's Executive Branch of Government.

DOTA is organized into five branches: Administrative, Operations, Engineering, Planning, and Information Systems. There are four District Offices overseeing fifteen airports (i.e., Oahu District (3 airports), Maui District (6 airports), Kauai District (2 airports), Hawaii District (4 airports)). The DOTA administrative offices are located at the Honolulu International Airport, Inter-island Terminal Building.

For more information visit http://hawaii.gov/dot/airports/ .

Forward-Looking Statements

This press release contains forward-looking statements that involve many risks and uncertainties. These statements relate to Hoku's ability to successfully complete the photovoltaic (PV) installation for DOTA in 2008, or at all; Hoku's ability to successfully identify third party financing for the procurement and construction of the PV systems; the expected power output of Hoku's PV systems; the expected performance and durability of Hoku's PV systems; Hoku's future financial performance; Hoku's business strategy and plans; and objectives of management for future operations. In some cases, you can identify forward-looking statements by terms such as "anticipate," "believe," "can," "continue," "could," "estimate," "expect," "intend," "may," "plan," "potential," "predict," "project," "should," "will," "would" and similar expressions intended to identify forward-looking statements. These statements involve known and unknown risks, uncertainties and other factors that may cause Hoku's actual results, performance, time frames or achievements to be materially different from any future results, performance, time frames or achievements expressed or implied by the forward-looking statements. Given these risks, uncertainties and other factors, you should not place undue reliance on these forward-looking statements. In evaluating these statements, you should specifically consider the risks described in Hoku's filings with the Securities and Exchange Commission. Except as required by law, Hoku assumes no obligation to update these forward-looking statements publicly, or to update the reasons actual results could differ materially from those anticipated in these forward-looking statements, even if new information becomes available in the future.