In a groundbreaking move towards a sustainable future, Hawaiʻi bid farewell to its last coal plant on September 1, 2022. This marked a crucial milestone in the state’s commitment to eliminating fossil-fueled electricity generation by 2045. However, the intriguing question arose: How can a reliable grid be maintained during the transition from traditional fossil plants to a diverse range of renewables dependent on unpredictable weather patterns?

The answer lies in an extraordinary solution – the Kapolei Energy Storage system. Developed by the Houston-based firm Plus Power, this colossal battery facility is unlike any other. Operating on the industrial west side of O’ahu, Kapolei boasts 158 Tesla Megapacks, charging and discharging based on signals from utility Hawaiian Electric.

The Powerhouse of Kapolei

The Kapolei Energy Storage system doesn’t just replace the coal plant; it surpasses its capabilities with a 185-megawatt instantaneous discharge capacity, coupled with an impressive 250-millisecond response time. Unlike traditional power generation, these batteries absorb electricity during renewable surpluses and release it during peak demand, providing a cleaner, more efficient energy solution.Brandon Keefe, Plus Power’s executive chair, expressed his enthusiasm, stating, “It feels incredible to be part of what Hawaiʻi and Hawaiian Electric are doing to get to 100 percent renewable energy and to play this enabling role to help them get one step closer.”

Overcoming Challenges and Setbacks

The road to Kapolei’s success wasn’t without challenges. Originally intended to come online before the coal plant’s retirement, the project faced delays, compounded by disruptions caused by the COVID-19 pandemic. Despite setbacks, Kapolei is now operational, making it one of the first large-scale projects to replace fossil fuel production with clean energy.

Replacing Key Coal Plant Functions

Grid batteries operate differently from traditional coal plants, requiring innovative approaches to ensure a seamless transition. Kapolei directly replaces the coal plant’s capacity and grid services. Its advanced features, such as synthetic inertia and fast frequency response, correct grid deviations in real time, maintaining stability even in the face of unexpected events.With 565 megawatt-hours of storage, Kapolei doesn’t replace the coal plant’s energy production but collaborates with the island’s solar sector to enhance the integration of clean renewable energy. Hawaiian Electric’s modeling indicates a 69 percent reduction in renewable curtailment for the first five years, allowing surplus clean electricity to be efficiently utilized.

The Most Advanced Battery Energy Storage Facility on the Planet

Keefe proudly dubs Kapolei as “the most advanced battery energy storage facility on the planet.” Its unique combination of capacity, grid services, and black-start capability makes it an unparalleled asset in Hawaiʻi’s clean energy transition.The advanced capabilities of the Kapolei Energy Storage system extend beyond its immediate functions. The battery plays a crucial role in stabilizing the grid by providing synthetic inertia, a function previously achieved through the spinning mass of traditional turbines in older power plants. Kapolei’s ability to emulate this process through advanced programming of its inverters not only ensures stability but does so without unnecessary carbon emissions.

Setting the Standard for Clean-Energy Grids

Hawaiʻi, a pioneer in renewable energy adoption, continues to lead the charge in the energy transition. Kapolei’s success underscores the need for innovative solutions as renewables outpace fossil-plant retirements. While other batteries provide frequency services, Kapolei stands out for its ability to combine peak capacity, frequency response, synthetic inertia, and grid-rebooting tasks.In a world moving towards maximizing renewable energy, Kapolei’s ability to provide synthetic inertia through advanced battery technology is crucial.

This ensures a more economical alternative to traditional methods while avoiding unnecessary carbon emissions. The project sets a precedent for the rest of the world, showcasing a real-life example of shifting critical grid functions from fossil-fueled to clean energy plants.As the United States and the world strive towards ambitious climate goals, projects like Kapolei highlight the necessity of transitioning away from fossil fuels and embracing innovative solutions for a sustainable future. The lessons learned from Kapolei will undoubtedly play a pivotal role in scaling similar initiatives nationwide, marking a significant step forward in the global clean energy revolution.

The Global Impact of Kapolei’s Breakthrough

Beyond its immediate impact on Hawaiʻi’s energy landscape, Kapolei’s success reverberates globally. As nations grapple with the need to transition to cleaner energy sources, the Kapolei Energy Storage system offers a tangible blueprint for success.In the pursuit of renewable energy goals, many regions face challenges in maintaining grid reliability during the shift from traditional power sources to renewables. Kapolei’s innovative approach demonstrates that it’s possible to not only replace fossil-fueled plants but also enhance grid capabilities with cutting-edge technology.

The Kapolei project’s success in reducing curtailment of renewables by an estimated 69 percent showcases the potential for large-scale battery storage to facilitate the integration of clean energy into existing grids. This reduction in curtailment means that surplus renewable energy, which would otherwise go to waste, can now be effectively utilized, contributing to a more sustainable and efficient energy ecosystem.

The Technological Advancements of Kapolei

Kapolei’s distinction as the most advanced battery energy storage facility on the planet is not merely a title; it represents a leap forward in technological innovation. The integration of 158 Tesla Megapacks with a 185-megawatt instantaneous discharge capacity highlights the scalability and efficiency of modern energy storage solutions. The use of synthetic inertia and fast frequency response positions Kapolei as a versatile asset in grid management. Synthetic inertia, traditionally provided by spinning turbines in older power plants, is emulated through advanced programming in Kapolei’s inverters. This not only ensures grid stability but does so with a level of precision and speed that surpasses traditional methods.

The Economic and Environmental Implications

Beyond its technological prowess, Kapolei’s impact extends to economic and environmental spheres. The reduction in renewable curtailment directly translates to economic benefits by maximizing the utilization of clean energy resources. The synergy between Kapolei and the island’s solar sector exemplifies how such projects can work in tandem to create a robust and sustainable energy infrastructure.Moreover, Kapolei’s ability to provide black-start capability adds an extra layer of resilience to Hawaiʻi’s grid. In the face of disasters such as cyclones or earthquakes that could potentially knock out the entire grid, Kapolei’s batteries hold energy in reserve to jump-start the system. This not only contributes to grid reliability but also aligns with broader resilience goals in the face of climate-related challenges.

Lessons for the Global Clean Energy Shift

As nations worldwide grapple with the imperative to transition away from fossil fuels, Kapolei stands as a beacon of success. Its comprehensive approach to replacing key coal plant functions while introducing innovative grid services sets a standard for the evolving landscape of clean energy. The shift towards a more renewable-centric grid model, as witnessed in Hawaiʻi, necessitates a paradigm where clean technologies not only contribute to energy generation but actively participate in maintaining grid stability. Kapolei’s ability to combine peak capacity, frequency response, synthetic inertia, and grid-rebooting tasks positions it as a model for future energy storage projects globally. The Kapolei Energy Storage system exemplifies the intersection of environmental stewardship and technological advancement. It’s not merely a local solution to Hawaiʻi’s energy needs; it’s a testament to what can be achieved on a global scale when innovation meets commitment.


In conclusion, the Kapolei Energy Storage system’s journey from conception to operational success is a narrative of resilience, innovation, and a commitment to a sustainable future. Hawaiʻi’s bold step in shutting down its last coal plant and replacing it with a cutting-edge battery facility showcases the state’s leadership in the global clean energy transition. Kapolei’s role in maintaining grid reliability, reducing renewable curtailment, and providing critical grid services positions it as a pioneering force in the clean energy landscape.

Beyond its immediate impact on Hawaiʻi, Kapolei serves as a model for other regions striving to balance the integration of renewables with grid stability. As the world seeks solutions to address climate change and transition towards cleaner energy sources, the lessons learned from Kapolei will undoubtedly shape the future of large-scale energy storage projects. The fusion of technological innovation, economic benefits, and environmental stewardship embodied by Kapolei paves the way for a more sustainable and resilient energy future globally.