Maui Electric Co.'s sales, measured in kilowatt-hours, are down nearly 10 percent this year, a drop that tracks closely with declining visitor arrivals, said company President Ed Reinhardt. Before the island's economic downturn and fewer visitors coming to the island, MECO had been forecasting that it would need its next increment of firm power generation in 2011. Earlier this year, because of declining demand, it revised that forecast to 2014.

With its ocean breezes, ample sunlight, pounding waves and a continuously erupting volcano, Hawaii seems blessed with the means to produce clean electricity and achieve energy independence. But that isn't anywhere close to happening. For one thing, the technology isn't quite ready. The big drawback with wind and solar energy, for example, is that the flow of electricity stops when the breeze dies down and the sun sets. Since there is no good way to store the power for use later, homeowners need conventional electrical service - meaning fossil fuel-burning plants - as a backup.

Down a dirt road on America's southernmost island, 16 windmills tilt their sleek blades toward the ocean, as dependent on the whims of Hawai'i's tropical breeze as residents are on the electricity they help produce. The Hawi wind farm on the Big Island makes clean and affordable energy, but the 100-foot-tall wind turbines stop when the air is still. Most forms of renewable energy face a similar difficulty nationwide - they're cleaner than oil and coal but fall short on reliability and convenience.