In May 2020, the Hawaii Public Utilities Commission (PUC) released its management audit of Hawaiian Electric. While many of those interested may have focused on areas ripe for efficiency enhancements and cost savings within the utility’s operations, the audit also revealed the vulnerability of the electrical grid — still heavily reliant on Hawaiian Electric’s aging fossil fueled generators.
Recent power shortfalls on both Oahu and Hawaii island serve as a stark reminder of the urgent need for a robust electrical system that offers reliability and resiliency, as well as affordability, in achieving the state’s ambitious target of 100% renewable energy across all island grids by 2045, using a diverse portfolio of resources.
However, without always-on renewable power sources, like geothermal and biomass, which have a much higher capacity factor than wind, solar and storage, the retirement of these aging fossil fuel plants is unlikely to happen soon, making the odds of a catastrophic event much higher whenever a major power plant shuts down for maintenance or breakdowns.
The state of Hawaiian Electric’s fossil fuel fleet underscores the urgent need for immediate action to secure reliable firm, high-capacity renewable energy sources like geothermal and biomass. Although the prospects for integrating new firm renewable power plants onto the grid appear daunting, and geothermal remains localized to Hawaii island, one technology — biomass — holds promise for statewide development. Already contributing around 10% of power to the Kauai Island Utility Cooperative grid, the Kauai biomass plant offers a compelling case study that points the direction for the rest of the state.
Beyond providing firm, clean renewable energy, the Kauai biomass plant delivers a range of ancillary benefits. It stimulates the growth of the nascent forestry industry by expanding the cultivation of eucalyptus crops for feedstock. The plant also delivers good-paying jobs and contributes to ecosystem improvement by turning invasive species, such as albizia, into feedstock.
Equipped with a state-of-the-art pollution control system, the Mahipapa (formerly Green Energy) biomass plant significantly mitigates the emission of particulate matter and nitrous oxides — a marked improvement over older biomass and fossil fuel plants.
Of special importance, and contrary to publicized claims, biomass stands out as the only renewable technology capable of a negative carbon footprint. This unique attribute stems from the ability of fast-growing fuel crops to absorb atmospheric carbon dioxide, neutralizing more greenhouse gases than the plant produces.
Trees that reach harvest size quickly, such as eucalyptus, have several characteristics that make them efficient at absorbing carbon dioxide, and thus better suited as biomass feedstock for carbon sequestration purposes. The reason these fast-growing trees are better include:
>> Rapid growth rate. They are marked by a higher rate of photosynthesis, the process by which they absorb carbon dioxide from the atmosphere and convert it into biomass. This means they can accumulate more carbon in a shorter time than slower-growing trees.
>> Higher biomass production. Due to their rapid growth, trees like eucalyptus produce more biomass per unit of time than slower-growing trees. This biomass represents stored carbon, as carbon is a major component of plant tissues such as cellulose and lignin.
>> Regeneration and harvesting. Tree crops that can be harvested in a few years and replanted quickly to maintain a continuous cycle of carbon sequestration.
Given these benefits, and in light of the reliability issues plaguing Hawaiian Electric’s aging fossil fuel plants, as well as its urgent need to become an all-renewable utility, Hawaiian Electric and the Hawaii PUC should seriously consider any biomass or other firm renewable energy providers that can become operational soonest, rather than creating roadblocks.
