SUMMER 2002 - The Moving Finger

Science musings from a desktop in West Oxfordshire

The Fuel of the Future?

I've just finished an article for 'Chemistry in Britain' magazine on the subject of methane hydrates. Methane hydrates are a weird form of crystallised gas that is found under the oceans and in permafrost areas such as the North Slope of Alaska and Siberia. It turns out that there is enough energy locked up in methane hydrates off the coast of America alone to fuel the entire USA for at least the next 350 years.

Man, that's a lot of gas.

So what are methane hydrates? They are molecules of the gas methane - CH4 - that are kept locked up in an enclosing bucky-ball of water molecules provided that the water is limited to a narrow range of temperature and pressure. These are conditions that are not normally found at the surface of the Earth but which do occur at shallow depths under the permafrost regions (where it is very cold) or which occur at the edges of the continental shelves where the slightly warmer temperatures are balanced by higher pressures.

Methane hydrate is strange stuff. It is ice that burns. Methane hydrates belong to a class of chemicals called clathrates - crystalline solids - that were discovered in the early 19th century by Sir Humphrey Davey. For years nobody thought that they were anything but a laboratory curiosity or a nuisance because they sometimes formed spontaneously in gas pipelines. That is until a bunch of Russians working in the Messoyakha gas field in 1964 discovered vast quantities of the stuff under the Siberian permafrost. Now that the Russians, Americans and Japanese have calculated just how much energy is stored in the world's methane hydrate reserves they are actively looking for the stuff all around the world's oceans and ice-caps.

They think that it will take the place of nuclear power.

But there is a sinister side to methane hydrate. Methane is a more potent greenhouse gas than carbon dioxide itself. If released - and it will be immediately and explosively as soon as its enclosing pressure and temperature prison is loosened - it could warm the Earth by up to 8oC. That's twice the temperature difference between us and the last ice age but in the warming rather than the cooling direction...

All best,

Richard

CLOSE ENCOUNTERS WITH CRYSTALLISED GAS will be published by Chemistry in Britain in the early summer 2002.

For more information about the climatic consequences of methane hydrates see my book ARCHITECTS OF ETERNITY.

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