Methane hydrates constitute the world’s No. 1 reservoir of fossil fuel. Ubiquitous along vast stretches of Earth’s continental shelves, they hold enough natural gas to fuel the world for a thousand years – and beyond.
In a joint announcement two weeks ago, the United States and Japan (along with ConocoPhillips, the U.S.-based multinational oil company) announced the world’s first successful field trial (in Alaska) of a technology that uses carbon dioxide to free natural gas from methane hydrates – the globally abundant hunks of porous ice that trap huge amounts of natural gas in deposits, onshore and offshore, around the world. It’s a neat feat. You use CO2, which isn’t wanted, to produce natural gas, which is. But it’s more than neat – much more.
Methane hydrates constitute the world’s No. 1 reservoir of fossil fuel. Ubiquitous along vast stretches of Earth’s continental shelves, they hold enough natural gas to fuel the world for a thousand years – and beyond. Who says so? Using the most conservative of assumptions, the U.S. Geological and Geophysical Service says so.
The U.S. now produces 21 trillion cubic feet (tcf) of natural gas a year. But it possesses 330,000 tcf of natural gas in its methane hydrate resource – theoretically enough to supply the country for 3,000 years (give or take). Using less conservative numbers (for example, a methane hydrate resource of 670,000 tcf), the U.S. is good to go for 6,000 years (give or take).
Worldwide, methane hydrate reserves add 1,000,000 tcf to the global natural gas resource. We have a ways to go before commercial exploitation begins but the question must now be asked: Isn’t it time to relax a bit about peak oil – or, for that matter, peak primary energy? We are not apt to run out of carbon to burn for a very long time. It is true: Only a fraction of these resources can be deemed economic in the near term. But a fraction of them could still deliver plentiful energy for many centuries.
According to one conservative academic calculation, Earth’s conventional reserves of natural gas hold 96 billion tonnes of carbon. Earth’s reserves of oil contain 160 billion tonnes. Earth’s reserves of coal contain 675 billion tonnes: Taken together, 931 billion tonnes of fossil fuel. But Earth’s methane hydrates contain 3,000 billion tons of carbon.
Or more. Methane hydrates are found at larger and larger volumes the deeper you drill. ConocoPhillips drilled 830 metres for its field test at Prudhoe Bay. At this level, you calculate the reservoir of methane gas in the hundreds (100s) of trillions of cubic feet (tcf). Drill deeper and you calculate reserves in the thousands (1,000s) of trillion cubic feet. Drill deeper still and you calculate reserves in the hundred-thousands (100,000s) of trillion cubic feet. Earth’s reserves of this resource could theoretically reach millions (1,000,000s) of trillion cubic feet.
Citing the first prolonged release of natural gas from methane hydrates, U.S. Energy Secretary Steven Chu celebrated the “enormous potential for U.S. economic and energy security” of the new technology. The U.S. has reserves of 2,600 tcf of conventional natural gas. The Gulf Coast alone holds methane hydrate reserves of 220,000 tcf – nearly 100 times as much. For the next technology trial, the partners will head to the Gulf.
The Arctic trial began (with drilling) on Feb. 15. It concluded on April 10 (when the experiment was arbitrarily ended). In the interim, the partners “safely extract[ed] a steady flow of natural gas from methane hydrates” for 30 consecutive days – the first-ever test of a technology that uses CO2 to capture the cleanest of the fossil fuels. (Using different technology in 2008, a Canada-Japan trial produced a continuous flow of natural gas from methane hydrates for six days.)
Methane hydrates are hunks of porous ice that grip natural gas molecules as they rise naturally from deep reservoirs under the Earth’s surface – and grip them tightly, under pressure, in cold waters. In the successful test this spring, ConocoPhillips used CO2 to relieve the pressure, causing the ice cages to open and to liberate the trapped gas.
Why trade CO2 for methane gas that, when burned, releases carbon dioxide? And isn’t methane gas especially dangerous? In Conoco’s revolutionary technology, the CO2 not only replaces freed methane but simultaneously disposes of waste CO2 from conventional oil field production. This isn’t zero sum. It’s net gain – which is why Energy Secretary Chu, a celebrated environmentalist, champions it. Mr. Chu says, incidentally, that methane hydrates could cut the price of natural gas, already cheap, by one-third – within 10 years.