NEWS : TECH (NFPC)

China Eyes Combustible Ice for Energy

Combustible ice sounds like it belongs in Star Trek--and from the photos it looks that way, too. While the reality isn't that extreme, this energy source does involve high-seas adventure, phase changes, and environmental quandaries.

Recently I saw a Xinhua article reporting that the Chinese government is going to increase its combustible ice exploration efforts in the country's western Qinghai Province, which is home to a deposit discovered last September. So, what's this mysterious substance? It's natural gas hydrate, a solid form of methane and water. Ah yes, natural gas. That should be familiar.

There are different types of these deposits. In China, the deposit is in a high, frozen plateau, but many are in marine sediments. Last summer American scientists on a research vessel in the Gulf of Mexico drilled exploratory holes to look for gas hydrates buried deep in the sand. They discovered pockets of highly concentrated gas hydrate--examples of a deposit type that is estimated to hold 6,700 trillion cubic feet of the gas in that area alone.

"A lot of people think of it as unstable," says U.S. Department of Energy's methane hydrate R&D manager Ray Boswell. "It's not particularly volatile." Boswell points out that we'd actually have to work to pull it across a phase boundary, so extraction means melting the solid substance into its water and methane gas components underground. That process could likely be done with existing technology. Boswell's work aims to provide a better scientific understanding of this energy source--where it is, what production would require, and how it exists in the natural environment--so that the public can make informed decisions about whether and how we pursue it.

In the meantime, some methane isn't waiting around to be extracted. University of Alaska Fairbanks professor Katey Walter Anthony studies how thawing permafrost is causing increased methane emissions. She's known for illustrating it by igniting a fireball.

Photo: Burning methane hydrate. Credit: IFM-GEOMAR.

The Stinky Smell of Success

We've been talking about serious trash power for a long time so it's rather--well, refreshing isn't the right word--exciting to see it put into practice. This month the Macarthur Resource Recovery Park in a suburb of Sydney, Australia, began accepting its first batch of garbage from 300,000 people in the area.

First the recyclables are sorted out and then billions of microbes (more bugs!) in giant tanks gobble up the refuse, producing methane for power. Unlike other setups that only snag 70 percent of the gas, this plant is expected to capture 100 percent of the methane emitted inside oxygen-free tanks.

The Sydney Morning Herald reported that the $49 million plant will stop 9,000 truckloads of trash from going into landfills annually. I had read that gasification plants have been built in Asia and Europe, but Macarthur Resource Recovery Park's operations manager Bruce Bailey told Fairfax Media that it's the first full-scale plant in the world using this technology. Meanwhile, plans for a similar waste-to-energy plant were recently approved in Ottawa, Canada. The PlascoEnergy Group's Canadian complex will be the first one in North America. They're getting warmer...

Photo: Macarthur Resource Recovery Park interior. Credit: WSN Environmental Solutions