I'm from the Big Island, in Hawaii.  Energy is mostly from oil there - all imported, and expensive.  Tourism is the biggest industry, so there's a lot of concern about the environment.  An oil spill at Waikiki would be devastating.  

So there has been a lot of interest in alternative energy.  Especially on the Big Island, which is the only island with active volcanos.  They were going to build geothermal plants there, and install an undersea cable to Honolulu, where most of the population lives.  

They did actually build a geothermal plant, and are still using it today.  It does work.  However, it proved to be much more expensive to build and maintain than they had hoped, and also more polluting.  They are not building any more, and are not planning to export electricity to other islands.  

There's also an ocean thermal plant, off the Kona shore.  It, too, works.  They also have side industries - lobster farms and such - that make use of the cold, nutrient rich water brought up from the ocean depths.  But it's still not really profitable, when you consider all the money the government has sunk into it.  It might be different once we're well past peak, but clearly, it's not going to provide the kind of energy oil does.