Near Honolulu, researchers are testing how to generate electricity from the energy in ocean waves. And Hawaii’s largest electric utility is among the first to widely use advanced “smart” inverters to help manage the flow of electricity from rooftop solar panels into the power grid.
Such projects help explain why Hawaii is becoming a laboratory for how to integrate wind, solar, geothermal, and other renewable energy into an electric power grid—something the state must do in order to meet its first-in-the-nation goal to use only renewable electricity in the future.
California approved a similar renewables mandate in 2018. But Hawaii is a lab for how to integrate renewable energy into the power grid because it already has the highest use of rooftop solar in the country and its power grids are small and completely isolated from one another, Andy Hoke, a senior engineer at the National Renewable Energy Laboratory, told Bloomberg Environment.
The Hawaii Legislature passed a law in 2015 requiring the state to obtain all of its electric power from renewables by 2045—a goal California, New York, and other states have tried to emulate.
“We definitely think of Hawaii as a ‘postcard from the future’ as to how renewables will attach to the grid,” Hoke said.
Challenges that could crop up with a widespread move to renewables are apt to appear more quickly on a smaller power grid, offering lessons to other states, he said.
Hawaii is embracing renewables because of its high electricity costs and its climate goals.
Isolated in the Pacific Ocean, the state uses crude oil imported from the U.S. mainland to generate most of its electricity.
That isolation contributes to the highest electricity costs in the country. Hawaii’s price of 33.8 cents per kilowatt-hour is more than triple that of Louisiana, where power is cheapest, according to Energy Information Administration data from January.
“I actually think that Hawaii has a much harder problem than California” to meet its renewable energy target, said Sally Benson, director of the Global Climate and Energy Project at Stanford University.
That’s because Hawaii has multiple disconnected power grids, one for each of its islands. Each power grid has to generate all of its own power because utilities can’t import electricity from other parts of the country.
In contrast, California can—and does—buy renewable electricity from other states because it is part of a Western power grid, Benson said.
That makes Hawaii a testing ground of how to use batteries and power inverters to keep an electric grid stable when the sun isn’t shining, the wind isn’t blowing, and there are no other outside sources of electricity, Benson said.
But Honolulu Mayor Kirk Caldwell called the state’s 2045 renewables mandate more “aspirational” than anything else.
“I don’t think we’re doing the steps we need to get there,” Caldwell said.
He said the islands would integrate renewables if they could find a way to build a grid connecting all the islands. The channels between the islands are thousands of feet deep—too deep for power lines.
Some residents worry that wind farms on Hawaii’s mountain ridges will become visual blight and harm wildlife in a biologically diverse region, and they will vehemently oppose proposed projects, he said.
“We have a lot of energy sources to pick from,” Caldwell said. “We need to do a better job of doing that.”
A Test Bed
Hawaii intentionally set out to become “an international test bed” for clean energy, Mark Glick, a faculty member at the Hawaii Natural Energy Institute at the University of Hawaii-Manoa, told Bloomberg Environment.
Without the help of neighboring power grids to provide electricity when locally-produced wind and solar can’t, the state offers technology providers “the most difficult challenge,” said Glick, a former administrator of the Hawaii State Energy Office.
A variety of companies and universities are investing in the state to develop smart grids, advanced microgrids, and solar power projects that use large batteries to store the electricity from solar power grids, he said.
“We’re largely on a solar-plus-storage path” to getting to the 100 percent renewable portfolio standard in Oahu, the state’s most populous island and site of the capital Honolulu, Glick said.
Solar Plus Storage
The state’s largest electric utility, Hawaiian Electric Cos., in January submitted contracts to the state’s utilities commission for seven large solar and electricity storage projects across the islands.
Those solar projects will generate electricity expected to cost between 8 and 12 cents per kilowatt-hour—a fraction of the cost of electricity generated using crude oil, according to the announcement.
Hawaiian Electric, which serves all the islands except Kauai, expects to achieve 70 percent renewables by 2040, spokesman Peter Rosegg told Bloomberg Environment.
He said Hawaii’s diverse renewable resources—including wind, solar, geothermal, and possibly offshore wind and bioenergy—will help ease the state’s way to the 100 percent renewables target, Rosegg said.
But there are many hurdles.
There isn’t a lot of space on Oahu for wind farms, and offshore wind turbines would have to float because of the depth of the ocean surrounding the islands, said Hoke, from the national renewable energy lab.
Floating offshore wind farms are rare worldwide and have never been built in the U.S.
Hawaii’s utilities also have to figure out how to effectively balance the use of electricity from the power grid with varying wind and sunshine that affects how much power comes from wind and solar farms, Hoke said.
Though Hawaii’s Big Island can harness abundant geothermal energy because of its volcanic activity, that same vulcanism threatens geothermal power plants.
The Big Island’s geothermal plant was partially destroyed in 2018 during the Kilauea volcano’s lower Puna eruption. The plant is expected to restart operations in 2020, Rosegg said.
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