There’s a lot of talk about making Hawaii “energy independent” by kicking our imported oil habit. State government has set a deadline of 2020 for utilities to generate at least 20 percent of their power from sources other than oil. But what could we use to power our grid? Here, we explore the alternative energy sources now being pursued in the Islands.
(page 3 of 4)
The state has a number of hydroelectric plants—generation units that are turned by the power of falling water. In terms of new construction, the main hydro discussion is its potential as what’s called “pumped storage.” This is a way of extending the working usefulness of intermittent power sources.
With wind, for instance, you could use the power to pump water into a high-elevation reservoir when the propellers are turning, and then run that water back down into a hydroelectric plant to produce energy when the wind isn’t blowing.
There probably isn’t room for enough upland reservoirs to effectively move windmills from the intermittent power to the firm power category, but the technique could certainly extend their usefulness.
The ocean itself is a vast reservoir of energy. One technology takes advantage of the physical movement of water—the motion of waves can be harnessed to power generators directly. One wave-energy plant is being tested off Kaneohe, and another is planned off Maui by a firm called Oceanlinx.
There also seems to be potential for making power from the difference in temperatures between surface and deep water off Hawaii. Most of the world’s Ocean Thermal Energy Conversion (OTEC) testing has been done in pilot projects off the Big Island, but while Hawaiian Electric lists it as a potential energy source, there is still no active commercial Hawaii project and, indeed, no large-scale OTEC facility anywhere in the world.
The Hawaii-based firm OCEES, for Ocean Engineering and Energy Systems, has a tentative agreement with the Navy to buy the power from a 13-megawatt OTEC plant to be installed off the tiny island of Diego Garcia in the Indian Ocean.
“Once you prove the first system works, we believe a lot of folks will adopt it, but it’s not easy to get the first one done. I would expect that we would have a system with 20 to 50 megawatts operational in Hawaii by 2020,” said OCEES president Harry Jackson.
Alternative energy advocate Henry Curtis, executive director of Life of the Land, said he believes OTEC could ultimately produce 40 percent to 50 percent of the state’s power—replacing oil as the primary electrical supplier.
Renewable power in Hawaii
Sources: Hawaiian Electric Co., Kauai Island Utility Co-op, government agencies and power providers.