Hawaii relies heavily on oil (which has to be imported) and as a result electricity prices are roughly two to five times the average price on the mainland. Hawaii is also home to multiple military bases and the headquarters for U.S. Pacific Command, which overseas military operations throughout Asia and the Pacific, over half of the world’s total area. Like the state of Hawaii, the military also has special energy needs. In the field, it’s reliance on fossil fuels requires expensive and vulnerable supply lines.

The U.S. Navy has paid Lockheed Martin $9.32 million to develop Ocean Thermal Energy Conversion (OTEC) technology, which uses temperature differences between warm surface waters and deep, cold water to generate power. (It can use a Rankine cycle that involves a liquid with a low boiling point. Warm sea water boils the liquid, producing steam that drives a turbine to generate electricity. Cold water condenses the coolant to a liquid to be reused.)

The military is also investing in solar-powered hydrogen production. This is in part to produce hydrogen for vehicles (either fuel cell cars or internal combustion engines made to burn hydrogen). What’s more interesting is the potential of hydrogen as an energy storage medium. A large part of wind power produced in Hawaii is wasted because the power is generated at night, when demand is low, and storing that energy as hydrogen, which can be used to generate electricity when it’s needed, could be cheaper (though much less efficient) than using batteries. The military could use solar powered hydrogen generation in the field to power its bases, without the need for supply trucks to deliver diesel for generators.

source: technologyreview.com