Hawaii says aloha to greener energy grid

The Kapolei Energy Storage (KES) facility run by Plus Power has begun operations in Oahu, Hawaii, touted as the most advanced grid-scale standalone battery energy storage system in the world. The facility replaces a defunct coal power plant and will support roughly one-fifth of the population's energy needs, including moderating renewables, reducing electricity bills, and protecting against blackouts.

Hawaii's infamous island prices for imported goods were never so alarmingly illustrated as by fossil-fueled electricity prices. With sun and wind in excess, America's tropical paradise is now pushing back with the world's most advanced renewable energy battery storage system.

Russia's invasion of Ukraine has only strengthened the state's embrace of renewable energy. Electricity rates in Hawaii sit at almost double the cost per kilowatt-hour of California due to many of its power plants burning a large percentage of oil, all of which is imported. (Originally, most of its oil has come from Russia, Libya, and Argentina, with only a small percentage coming out of Alaska.) Many of Hawaii's single-family homes have rooftop solar panels, more than double the percentage in other sunny states like California and Florida.

Headquartered in Houston, Texas, with offices in San Francisco, Chicago, and Miami, Plus Power is an industry leader in the rapid deployment of transmission-connected battery energy storage throughout the U.S. – developing, owning, and operating standalone battery storage systems that provide capacity, energy and ancillary services for integration of renewable resources. The company has a growing development portfolio of KES-scale battery systems across 28 U.S. states and Canada, with over $1.8 billion in project financings as of October 2023.

"Plus Power is in the business of solving hard climate problems," said Plus Power Executive Chairman Brandon Keefe. "Our projects, like KES, help our customers provide affordable, reliable, clean electricity on hot summer afternoons and cold winter nights, while enabling the decarbonization of the electric grid."

Oahu's big batteries

The KES consists of roughly eight acres of land in Kapolei on the southwest side of the island of Oahu, using 158 Tesla Megapack 2XL lithium iron phosphate batteries. Each is about the size of a shipping container and collectively presents the grid with an additional 185 megawatts of total power capacity and 565 megawatt-hours of electricity, acting as a lightning-fast (250 milliseconds) electrical safeguard that grid operators can call on at times of high demand. Batteries are light-years faster than the inefficient and costly combustion-powered peaker plants, which take several minutes to come online.

Plus Power

The Kapolei Energy Storage facility marks the first time batteries have been used by a major utility to provide such a diverse range of grid-forming services, enabling more renewable energy in Hawaii.

"This is a landmark milestone in the transition to clean energy," said Keefe. "It's the first time a battery has been used by a major utility to balance the grid: providing fast frequency response, synthetic inertia, and black start. This project is a postcard from the future - batteries will soon be providing these services, at scale, on the mainland."

"KES is an important part of a portfolio of resources that work together to provide reliability and energy security on Oahu's isolated island grid," said Jim Alberts, senior vice president and chief operations officer of Hawaiian Electric. "Energy storage technology that responds quickly to constantly changing conditions is an essential tool for us to use to manage the grid and operate it as efficiently as possible."

Customer-generated solar power oversaturation (excess energy sent back into the grid) has become so prevalent that Hawaiian Electric must regularly turn off large volumes of existing utility-scale solar and wind to keep the electric system in balance.

Meanwhile, it is expected that across its first five years in operation, the KES plant will reduce this type of renewable energy curtailment by more than half, help scale up grid renewables, reduce reliance on fuel, and provide flexibility for the continued growth of private, decentralized power from rooftop solar.

"No one has used batteries to provide such a diverse range of grid-forming services at this scale before in the world," Keefe said. The plant is also near three critical power generation facilities, enabling power plant reboot in the event of an island-wide emergency.

The KES batteries will help take up the grid capacity formerly provided by an AES coal power plant, which closed in September 2022, replacing production of a fifth of the power used by Oahu's population – just short of a million people – and Air Force, Army, Navy, and Marine Corps bases.

"This project provides another example of Hawai'i's leadership in the clean energy transition," said Hawai'i's Chief Energy Officer Mark Glick. "The grid modernization strategies employed by Plus Power support a cleaner, more reliable and more affordable energy system."