Methane hydrates.

If you know anything about methane gas – and the Office of Naval Research thinks you should – it probably has something to do with swamp gas, and a faintly unpleasant sulfurous smell that rises from country marshes on sultry, summer evenings, or perhaps – for more romantic types – stories of Will-o'-the-Wisp, the flickering lights seen at night above that very same swamp (mundanely, methane igniting spontaneously with traces of odorous hydrogen sulfide found in the bog's rotting organic matter).

Forget it.

Start thinking about methane hydrates - a crystalline form of methane gas and pure water that exists when pressures are sufficiently high, or temperatures sufficiently low. If you manage to keep that pressure high or that temperature low, it looks like a lump of ice. There are mega-tons of the stuff at the bottom of the ocean all over the world and in the Arctic permafrost (about 300,000 trillion cubic feet of it) and it is the cleanest and most abundant source of energy in the world. There is at least twice as much of it around as fossil fuels (some say 10 times as much). And, when burned as a fuel, it releases less carbon dioxide pollution than anything else around.

So why aren't we using it?

Plain and simple, methane hydrates are hard to get at, and once gotten at, hard to transport. Its crystalline form will change to gas when pressures are lowered, or temperatures rise (like when it's brought to the sea surface) and in doing so it will expand 164 times, representing definite storage and transport issues. There are geo-political considerations, too – who owns it? What about global warming (because extra methane, when released, is another addition to the greenhouse gases)? And, naturally occurring submarine landslides, which in turn create tsunamis and cause costly damage to pipelines and undersea cables, may be caused by hydrate dissociation and sediment failure; that is, landslides may occur if the substrate becomes lubricated when the crystalline form reverts to gas and water. If we exploit the resource, are we exacerbating the problem?

Diving on hydrate mounds in the Gulf of Mexico, from the Edmund Link on the Johnson Sea Link submersible.

All these issues are being addressed in a series of international conferences entitled 'Fiery Ice from the Sea.' "Many technological problems need to be resolved," says Nick Langhorne, science officer in ONR's London office, "And these need a coordinated international effort. There will always be nuclear energy, of course, but nuclear power comes with a lot of emotional baggage and, while it's good for generating electricity, chances are you'll never run your car on it. It's time to put the necessary resources toward methane hydrates R&D."

The world consumes 3 billion gallons of oil a day. The Navy alone uses over 4 million gallons of it a day, and that's in peacetime. Production and supply of all the traditional hydrocarbon fuels – coal, gas and oil – are well established but will peak by the year 2010.

"And there's another bonus in all this," says Rick Coffin, of the Naval Research Lab. "When methane, which is a gas, combines with seawater to make methane hydrate, it rejects the salt in the water. Therefore, fresh water is produced when the concentrated hydrates are melted. It's a desalination process where the methane can be recycled to continue the process. For areas thirsty for water, this could be a real windfall. Perhaps I should have said 'waterfall.'"