Hawaii sees hydrogen as a route to energy independence, but it will need to overcome obstacles facing its production writes Emmeline Willey.
Like many other archipelagos and islands, Hawaii is heavily dependent on fossil fuel imports — the state spends nearly $2 bn/yr on petroleum — but it sees hydrogen as a route out of its dependence.
Since 2008, Hawaii has targeted a 100pc renewable energy portfolio by 2045, with some success so far. In 2020, 36.1pc of electricity sales came from renewable sources, up from 29.8pc in 2019, state data show.
Hawaii already uses hydrogen in its energy mix — utility Hawaii Gas runs a 9-12pc hydrogen mix with its synthetic natural gas in more than 1,100 miles of pipeline on the island of Oahu, where most people in the state live. The hydrogen is a result of the synthetic gas production process, which uses naphtha by-product from petroleum refining. Hawaii Gas says it may consider adding more hydrogen to its pipelines should more green hydrogen production come on line.
Hawaii has also produced hydrogen from electrolysers for over a decade, but on a small scale that can be measured in kilogrammes rather than tonnes per day.
To scale up electrolytic hydrogen production, Hawaii will need to increase its geothermal power production. Oahu would need 180MW of reliable geothermal power to be able to run on hydrogen, energy solutions firm NorthStar Energy's Riley Saito says. Geothermal hydrogen production was identified as a goal in the Hawaii Natural Energy Institute's 2010 hydrogen strategy but this has yet to be realised.
The state has some geothermal power production at the Puna Geothermal Venture (PGV) plant but, after running quietly and reliably for 20 years, it was damaged in the 2018 Puna volcanic eruption. The plant is being rebuilt and is currently running at 25MW, with the goal of being up to 46MW, Saito says.
The PGV plant was constructed in the island's Lava Zone 1, putting it at risk of future eruptions. Geothermal power does not have to be sited on active volcanoes and Hawaii is home to many "hot spots" with untapped geothermal potential. These could supply all of Hawaii's needs, including its transportation sector and airlines, Saito says. The key will be to "make it acceptable to the people on a small scale". Misinformation and confusion following the 2018 eruption led to controversy over the stability of geothermal installations, and the public commonly mistakes it for a type of fracking, Saito says.
Geothermal plants tend to run 24/7 on a closed-loop system, so are unable to quickly ramp up or down. This can lead to wasted energy in times of low electricity demand. A robust energy storage option — such as hydrogen — could make plants more economically viable, executive director of nonprofit Life of the Land Henry Curtis says.
Setting an example
Many islands struggle with an energy supply that is expensive, dirty and insecure. Some, such as Dominica in the Caribbean, are exploring geothermal hydrogen as a way of improving this situation. Others, such as Puerto Rico, have paid some lip service to hydrogen but have yet to announce any solid plans.
Iceland and New Zealand are in a stronger position. Both countries already have high levels of hydropower and geothermal in their energy mix, which they may leverage for green hydrogen production.
Hawaii is set to update its 2010 hydrogen strategy. A bill currently before the Hawaii state legislature would require the Natural Energy Institute to conduct a study and release a new strategic hydrogen plan for 2023-2050. If it can lay the foundations to develop a hydrogen economy, the state could become a role model for many other islands that lack traditional energy sources.
