Clean Energy Facts

About Our Fuel Mix

Generation of renewable energy continues to increase

In 2018, nearly 27 percent of the energy used by customers of the Hawaiian Electric Companies came from renewable resources, even with the loss of Hawaii Island’s geothermal resource for most of the year following the Kilauea volcanic eruption. These results, presented in our Renewable Portfolio Standard report to the Public Utilities Commission, include power generated by customer-sited, grid-connected technologies, such as private photovoltaic (PV) systems.

Six grid-scale solar-plus-battery storage projects, the largest and lowest-cost portfolio of renewable energy resources to be assembled at one time in Hawaii, were approved in March 2019 by the Public Utilities Commission (PUC).

Three projects on Oahu, one on Maui and two on Hawaii Island will add 247 megawatts (MW) of solar energy with almost 1 gigawatt hour of storage. Each project is coupled with battery storage that can release four hours of energy to further reduce fossil fuel use during peak demand in the evening or at other times of the day when the sun isn't shining.

The following charts display the mix of fuels used to generate the electricity produced by each of our three utilities and the electricity purchased from independent power producers.


On Oahu

In 2018, 19 percent of the electricity generated by Hawaiian Electric, contracted independent power producers, and small feed-in tariff facilities was fueled by renewable resources, including solid waste, wind, solar, and biofuel energy. This percentage includes customer-sited rooftop solar systems.

As of April 2019, progress continued on several renewable energy projects on Oahu:

  • The 50-MW Schofield Generation Station, powered by a biofuel/diesel blend, went into service in June 2018.
  • The 24-MW Na Pua Makani wind farm in Kahuku remains in development.
  • West Loch PV, a 20-MW facility at Joint Base Pearl Harbor-Hickam is planned come online this year.
  • Three Clearway Energy solar facilities totaling 110 MW will come online this year.
  • Two additional Clearway Energy solar-plus-battery projects, Mililani I Solar (39-MW/156-MWh storage) & Waiawa Solar (36-MW/144-MWh storage), were approved by regulators in March 2019.
  • Hoohana Solar I (52-MW/208-MWh storage), a 174 Power Global project that will also supply solar-plus-battery, was approved by regulators in March 2019.
  • Another 12.5-MW solar array in West Oahu that will include a 50-MWh battery storage system is under review by regulators.
Oahu Fuel Mix

On Hawaii Island

In 2018, 36 percent of the electricity generated by Hawaii Electric Light, contracted independent power producers, and small feed-in tariff facilities was fueled by renewable resources, including geothermal, wind, hydro, and solar energy. This percentage includes customer-sited rooftop solar systems, and takes into account the loss of the island’s geothermal resource since May 2018 following the volcanic eruption.

In addition to our hydroelectric plants, Puueo 1, Puueo 2, Waiau 1, and Waiau 2, Hawaii Island residents benefit from renewable energy produced by independent power producers:

  • 38-MW Puna Geothermal Venture facility was damaged and shut down by the Kilauea eruption in 2018, but is scheduled to be repaired and returned to service in 2020.
  • Two wind farms: 10.5-MW Hawi Wind Farm and 20.5-MW Pakini Nui
  • Wailuku River Hydroelectric and several other small hydro plants
  • Small feed-in tariff projects are under development.
  • Construction continues on Hu Honua Bioenergy, a 30-MW firm, renewable power plant at Pepeekeo to be fueled by locally grown eucalyptus trees.
  • Waikoloa Solar, a 30-MW AES project with 120-MWh battery storage was approved by regulators in March 2019.
  • Hale Kuawehi a 30-MW Innergex project with 120-MWh battery storage was approved by regulators in March 2019.
Hawaii Island Fuel Mix

In Maui County

In 2018, 32 percent of the electricity generated by Maui Electric, contracted independent power producers, and small feed-in tariff facilities was fueled by renewable resources, including wind, solar, biomass, biofuel, and hydro energy. This percentage includes customer-sited rooftop solar systems.

As of April 2019, progress continued on several solar projects in Maui County:

  • The 2.87-MW Kuia Solar facility came online in 2018.
  • The 2.87-MW South Maui Renewable Resources solar facility came online in 2018.
  • Molokai New Energy Partners’ 2.7 MW solar project with a 3-MW/15-MWh energy storage system was approved by regulators in 2018.
  • Kuihelani Solar, a 60-MW/240-MWh solar-plus-battery storage AES project was approved by regulators in March 2019.
  • An additional 15-MW solar-plus-battery storage project that will provide 60-MWh of storage is currently under review by regulators.
  • Small feed-in tariff PV projects are under development.
Maui Fuel Mix

The following table shows the mix of fuels used to generate electricity for delivery to customers in each of our service areas in 2018.

Fuel Mix in Our Service Areas - 2018 Calendar Year

Fuel Sources Hawaiian Electric
(Island of Oahu) 
Hawaii Electric Light
(Island of Hawaii) 
Maui Electric
(Islands of Maui, Molokai, and Lanai) 
Oil 63.15% 63.72% 68.19%
Coal 17.51% 0 0
Biofuel 0.82% 0 0.07%
Biomass 0 0 0
Geothermal 0 8.61% 0
Hydro 0 4.88% 0.27%
Solar 10.61% 11.33% 12.00%
Solid Waste 5.22% 0 0
Wind 2.69% 11.46% 19.47%
TOTAL: 100% 100% 100%
Total from Renewable Resources 19.34% 36.28% 31.81%