Let's see....you can start with the natural sources that only the U.S. has and then add to it the simple process of electrolysis (oil powered electricity or solar), the developing direct thermal production using the old nozzle skimmers and the sun, biological methods using green algae or bacteria, lots of methods.
Electrolysis is surprisingly efficient - no fundemental thermodynamic limitation so conversion can be nearly 100%. With the algae, the process becomes simple as fermentation of beer.
Hydrogen or fuel cells have potential. A silly appearing phrase for Bush to use in the SOTU, true, but it is any idea worthy of support.