Although 30% of the Hawaii Clean Energy Initiative's target will be met through energy conservation, much of the roughly 1.4GW needed for the remaining 40% as clean energy will come from wind generation in a state stalled at four wind farms and 63MW since 2006.
Deployments are picking up with a few projects expected to come online within two years. Massachusetts-based First Wind is adding 21MW to its operational 30MW Kaheawa wind farm on Maui. It will also add two wind farms at Oahu - a 30MW Kahuku project in 2011 and a 70MW Kawailoa project in 2012. San Diego-based Sempra Generation is working on a 22MW wind farm on Maui, while Kauai Electric Utility Co-operative has plans for a 10-15MW project on Oahu.
Efforts will also include undersea transmission cables, battery storage and a new way of converting alternating current to direct current, resulting in an unusually wind-heavy and isolated electrical grid.
The US Department of Energy's National Renewable Energy Laboratory established a Hawaiian outpost in 2008 and is studying the situation along with the State of Hawaii, the utility Hawaiian Electric Company and other stakeholders. "It involves lots of renewable energy on a very small grid, which is very challenging," says David Corbus, a senior engineer at the laboraty. "A lot of issues we would see on the mainland many years from now, in terms of high penetration, we'll encounter much earlier in Hawaii."
Big wind
The biggest plan in the longer term involves two 200MW projects, one by First Wind and the other by Castle & Cooke. Combined, they will require some 200 kilometres of undersea cables to bring power from the sparsely populated islands of Molokai and Lanai to Oahu and its 900,000 residents. "We call it Big Wind," says Corbus. "And the timeframe would be to move forward fairly quickly."
However, the undersea cabling connecting the islands will cost $1 billion or more. "But we spend about $6 billion a year on oil to power our economy ... it just leaves the state and that's the last we ever see of it," says Joshua Strickler, facilitator of the state's renewables programmes. "So, $1 billion is a big number but we're spending it already."
As for other technology, a 10MW battery system on First Wind's Kahuku project will help balance wind on the grid. "It's not meant for long-term storage," says Kekoa Kaluhiwa, the company's director of Hawaiian external affairs. "It will be used for its ability to smooth out fluctuations in output, which the utility is asking us to do."
New technology is also being examined for high-voltage direct-current (HVDC) conversion on the Big Wind projects, says Corbus. "Typical HVDC systems have been current-source configurations, but this is a voltage-source configuration," he says. This provides better power control. "Studying the interaction of that converter with the actual wind plant controls has been very interesting and will provide very useful results for potential offshore elsewhere."
