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Hawaii's Solar Energy Revolution

How the proliferation of solar panels on Honolulu homes will force Hawaiian Electric Co. to reinvent itself—or else.


(page 4 of 4)


Hawaii has a rich variety of potential renewable energy sources. Here's a quick guide.



Nearly one out of 10 residential rooftops on Oahu is now adorned with solar photovoltaic panels. There’s so much PV out there that Hawaiian Electric Co. has slapped a virtual moratorium on adding any more in some neighborhoods while it studies the technical issues involved with having unprecedented amounts homemade power on the grid. (See main story.)

Meanwhile, HECO is seeking fast-track approval from the Public Utilities Commission to have nine large-scale solar farms developed. They would produce about 240 megawatts of power and offer some relief to ratepayers from the high cost of fuel oil. The utility says power from the solar farms would cost about 15.8 cents per kilowatt hour, compared with rates as high as 22.7 cents per kilowatt hour at its fossil-fuel-fired power plants.

What to watch: Where will all of these solar farms be built? How much land will they need? And which—if any—of HECO’s fossil-fuel-run power stations will be decommissioned when the solar farms come online? So far, HECO’s not saying.


A proposed wind farm on Molokai was defeated by intense local resistance. A similar project on Lanai appears all but dead. Kauai might have too many endangered native birds to introduce the giant, bird-killing blades of wind turbines into the environment. But successful wind farms have been built on Oahu, Maui and the Big Island. Their combined output accounts for some 30 percent of all the renewable energy in the state.

While Maui and the Big Island have Hawaii’s best wind-farm-quality wind, O‘ahu is doing its part with two wind farms on the North Shore. The 30-megawatt, 12-turbine Kahuku Wind Farm began generating electricity in 2011. A 2012 battery fire knocked it out of commission for more than a year, but it went back online in late 2013. Also in 2012, the 69-megawatt Kawailoa

Wind project on the hills outside of Haleiwa came online. Its 30 enormous turbines can be seen for miles around, outraging some North Shore residents who object to the visual impact. A third wind farm has been proposed for development in Kahuku, but it’s far from a done deal.

What to watch: The Oahu-Maui grid tie-in. Oahu doesn’t have the best wind or many more suitable sites for wind farms, but Maui’s got wind to spare. If the interisland cable connection that the state is pushing becomes reality, wind power could light up more Honolulu homes than ever.


The development of geothermal energy, which taps volcanic steam found a mile or more beneath the earth’s surface, is a high priority among state energy planners. Hawaii’s only existing geothermal plant, Puna Geothermal Venture, produces about 20 percent of all the renewable energy generated in the state—every watt of which stays on the Big Island. The Island’s electric utility, the Hawaii Electric Light Co., wants to up the Island’s current 38 megawatts of production to 88 megawatts. The state and Hawaii County are battling over who gets to decide where that future development would occur. Meanwhile, an anti-geothermal movement in Puna is trying to block further development there, and former Native Hawaiian opponents of geothermal—including Mililani Trask—are now part of a venture seeking to land the next geothermal
development contract.

What to watch: The interisland cable grid tie. Ultimately, the state wants to connect the electrical grids of Oahu, Maui and the Big Island via undersea cables. If it succeeds, Big Island volcanoes could one day illuminate Honolulu’s skyline.


Basically, anything that can be burned to produce power counts as biomass. In Hawaii that ranges from the municipal waste incinerated at Honolulu County’s HPOWER plant to the eucalyptus trees Hawaii Electric Light Co. plans to burn on the Big Island.

What to watch: A Mainland company called Zilkha Biomass Energy is vying to supply HECO’s Kalaeloa power plant with “black pellets” made from diseased trees harvested from the pine-bark-beetle-infested forests of British Columbia.


Hawaii’s granddaddy of renewables dates to 1888, when the newfangled electric light bulbs of Honolulu were powered by turbines spun by the flowing water of Nuuanu Stream. Hydro no longer lights the city, but it still has a place on Neighbor Island electric grids. Eight hydro plants on rainy Kauai (including one dating to 1908) generate nearly 10 percent of the Island’s power. According to a 2013 study by the Oak Ridge National Laboratory National Hydropower Asset Assessment Program, Hawaii has the potential to develop 145 megawatts of new hydropower.

What to watch: Molokai. A proposed project there would use excess solar power to pump water to an uphill storage reservoir during the day. At night, the water would flow to a lower reservoir, generating hydropower along the way. This “pumped storage hydro” project is in the early stages of development, but if all goes as planned, it could produce 80 to 90 percent of Molokai’s electricity.


Experiments in harnessing wave energy have been underway in the waters off Marine Corps Base Hawaii since 2004. A milestone was reached in 2010 when the first wave-generated electricity ever transmitted to a U.S. electrical grid was produced by a yellow, 40-kilowatt buoy bobbing off the base. The research continues.

Meanwhile, at Keahole Point on the Big Island, research continues into ocean thermal energy conversion (OTEC), which generates power using the temperature differences between deep sea water and warm surface waters. OTEC has been in development since the 1970s, but no commercial OTEC plant has been built. Yet.

What to watch: HECO has been in talks with a handful of developers to build an OTEC plant on O‘ahu’s west side. Look for a possible deal to be announced this year.


Biofuels offer the promise of replacing or blending liquid fossil fuels with liquid fuel made from plant oils. Biodiesel, for instance, has long been made in the Islands from used cooking oil and grease trap waste from restaurants. Fuel oil and jet fuel can also be produced from vegetable oils. According to the Hawaii State Energy Office, Hawaii has 136,000 acres of unused farm land that could be planted in biofuel crops—enough to produce roughly 160 million gallons of oil per year. If industrial scale production of biofuel crops on agricultural land ever takes off, it will require massive amounts of water, which will inevitably lead to conflicts.

What to watch: Algae. Are these fast-growing aquatic life forms the biofuel crop of the future? A pilot project using marine algae to produce biofuel is underway on the Big Island, and another is planned for a 34-acre site near Wahiawa.


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