On Tuesday, I wrote a column about the media’s failure to cover the opening of the world’s first coal-fired power plant with a fully integrated carbon capture and storage system. Given the adolescent nature of the technology it might not have been such a big deal, I reasoned—but the fact that both U.S. presidential candidates have made CCS a central promise of their campaigns makes the plant all the more relevant.
A lot of people argue, quite correctly, that “clean coal,” a nickname for CCS systems, is an oxymoronic advertising ploy. Part of the reason for that, as one savvy reader noted in a comment under my column, is that, “This unproven technology does nothing to stop the enormously destructive operations of coal mining.”
“Agreed,” I replied in a second comment. “CCS has nothing to do with the mining of coal, only the processing thereof.”
It turns out that while that is still largely true, it may not always be so. Last Monday, The Wall Street Journal published another of its excellent Journal Reports on energy, the paper’s seventh pullout section on the subject. Among other gems, it contained a very intriguing article about underground coal gasification (UCG), a different type of CCS (the new German plant uses oxyfuel combustion and other demo plants are using pre- and post-combustion methods) that burns coal without mining it. According to the article, “India and China are at the forefront” of developing the technology:
The Asian giants are investigating large-scale commercial projects that would produce energy by burning the coal where it lies, deep below the Earth’s surface. Building on pilot projects in the U.S. and elsewhere, the two countries are also looking at the possibility of capturing and permanently storing underground the gases produced, like carbon dioxide, which scientists believe cause global warming.
The underlying technology is one pioneered by the Soviets during the 1930s, called underground coal gasification - a way to tap energy from coal that was impossible or too costly to bring to the surface. A borehole is drilled down to the coal seam, which is then ignited. Oxygen is forced down through the borehole to feed the combustion. Gases produced by the combustion are then forced out a second borehole to the surface, where they are harnessed to turn turbines or for the production of chemicals. A power plant in Uzbekistan has been using the process for nearly 50 years. But elsewhere the practice was largely abandoned as increasing reserves of oil and natural gas were discovered, providing a cheaper alternative.
Because UCG was not cost-effective, it also faded from news pages after some early coverage. In 1980, Canada’s Globe and Mail ran a interesting article (unavailable online except through Lexis-Nexis or Factiva) about UCG with the soon-to-be-moot headline, “U.S. leads in underground coal gasification.” It reported that “three dozen companies - ranging from oil giants to local power companies” had expressed interest in a Department of Energy program to share UCG with private industry. It then went on to give a fairly detailed description of the burning process, and, despite the fact that cognizance of global warming was still many years off, noted that other environmental concerns were already at play:
Little pollution will escape into the atmosphere (coal acts like a charcoal filter, trapping many waste combustion products), but water supplies may become contaminated by trace elements and heavy metals released from the coal. If a coal field is exploited economically, drilling rigs, air compressors and pipework will litter the landscape.
Indeed, in 1984, just before UCG all but disappeared as a topic of conversation, The New York Times published an article with the headline, “Proposal to burn coal underground stirs protest in Pennsylvania town.” The project’s opponents feared that “the coal could burn out of control, ruining their homes and their valley, like the [mine] fire that has been burning for 20 years only 10 miles away and is now forcing the evacuation of the town of Centralia.”
Last week’s Journal article mentioned that groundwater contamination is a lingering concern, as is the possibility that UCG could “cause serious incidents of subsidence, which involves land sinking into the cavities created when the coal seams are drilled and burned out.”