Hawaii says goodbye to coal, aloha to big batteries

hawaii big battery kapolei
Image: Kapolei Energy Storage

For most visitors, Hawaii is where you go to relax, honeymoon and get away from it all. For Hawaiians, it is home, with all its warts and blemishes including high prices – including electricity prices.

The state used to be nearly 100% dependent on imported oil and diesel for power generation until 1980s, when it began importing coal. In 2015, the Aloha State passed a bill with the goal of becoming 100% renewable by 2045 – the first state in the US to do so.

It is also a leader in rooftop solar installations, twice the US average. Despite the lofty goals and the progress, it remains the most petroleum-dependent state in America.

As reported in the June 30 issue of EcoNet News, in September Hawaii will shut down its last coal burning power plant, the Kapolei station on the island of Oahu.

It will be partially replaced with the nearby Kapolei Energy Storage facility. A 185MW/565MWh battery energy storage system (ESS), among the largest in the world, is being built by Plus Power in record time. It consists of 158 Tesla Megapacks, which are being shipped to Oahu and assembled in time for the coal plant’s closure.

The state’s main utility, Hawaiian Electric Co (HECO) is also racing to build or acquire more renewable capacity as fast as it can including utility-scale solar, distributed solar, wind biomass and biofuels.

It has issued a number of Request for Proposals (RFPs), to bring more renewable capacity online to ramp down the use of imported oil and to replace fossil fuel generation on Oahu and the neighboring islands.

In the most populous island of Oahu, HECO is seeking up to 500MW of renewables by 2029 and an additional 200 MW by 2033. For Maui, at least 40 MW of firm capacity by 2027. Thus far, it has managed 600MW of solar and 3GWh of storage to be in service by 2024.

But that is not enough. To get to the 100% renewable target by 2045, more renewables, utility-scale as well as distributed will be needed. Given its year-round sunny climate and high retail rates, rooftop solar looks promising.

Hawaii was inundated with rooftop solar leading to a virtual moratorium in 2015 and revisions to the state’s net energy metering (NEM) laws.

Utilities complained that they could not handle more rooftop solar, which was flooding the local distribution network during sunny hours of the day (visual) and draining much needed revenues from HECO.

A new way had to be found to make it a win-win for both the utility and the customers. The obvious solution was to pair solar with batteries.

As reported by EcoNet News, in 2021, HECO offered $850/kW for a 10-year commitment to solar customers with batteries if they agreed to discharge at peak times but got little uptake.

Earlier this year, with the consent of the Hawaii Public Utilities Commission (HPUC), HECO introduced solar-plus battery scheme with a peak capacity payment of $5 per kW per month and an export credit for power flowing from the batteries to the grid at full retail rate between 6-8 pm when the network needs it the most.

This new export credit scheme rewards solar customers with batteries who can support the grid rather than forcing the utility to buy the excess solar when they don’t need it during the mid-day hours.

It is a win-win and is expected to attract more participation since increasingly customers pair solar with storage anyway. It resembles, in Australia, EnergyAustralia’s offer.

Other states with high rooftop solar penetration such as California, should emulate Hawaii’s solar-plus-battery scheme by turning the mid-day solar – considered a nuisance – into a valuable product by incentivising the discharging of the batteries after the sun has set. It is a classic case of turning lemons into lemonade.

This article was originally published by EEnergy Informer. Reproduced here with permission

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