Hawaiʻi’s LNG Bridge Has An Expensive Exit

Hawaiʻi is weighing a plan to bring in liquefied natural gas (LNG) as a temporary replacement for oil on Oʻahu. The catch is that state law requires electric utilities to reach 100% renewable generation by 2045, so LNG would eventually have to be swapped out for something else. One option state officials have floated is imported green ammonia, made by using renewable electricity overseas to produce hydrogen, converting it to ammonia, shipping it to Hawaiʻi, then converting it back to make electricity. A new analysis finds that pathway would be costly: LNG generation comes out to roughly 21 cents per kilowatt-hour in the model, versus about 95 cents per kilowatt-hour for the green-ammonia case, because each conversion step loses energy and adds cost.

The analysis also looked at what this means for a typical Oʻahu home. A modeled house with a 6-kilowatt rooftop solar system, a 10-kilowatt-hour battery, and a water heater set to run during the day could cover about three-quarters of its electricity use, paying back its cost in about 8.4 years under current rates and with a state tax credit. If electricity prices rose to reflect the expensive ammonia pathway, that payback would shrink to about 4.4 years, meaning homes that generate and store their own power would be far more insulated from the cost of imported fuel.

The broader point: as more homes and businesses add solar and batteries, a gas plant sells less power, raising costs per unit for whoever still relies on it. The analysis argues a mostly local system — rooftop and parking-lot solar, batteries, smart EV charging and water heating, plus some wind and backup fuel — could sidestep that problem entirely, though it still requires grid upgrades and investment to build out.