Bury it, forget it?

Till such time when nanotechnology and microbes that take in carbon dioxide and spew fuel (methane) step out of the realm of possibilities, most of the world will continue to rely on coal for their primary energy needs.

But, coal, everyone knows is not a honourable gas. That being so, how does one take the bite out of coal? CCS or carbon capture and sequestration. Here, the carbon emitted by thermal plants is captured and buried underground. Out of sight, out of mind.

But as some natural worriers have been pointing out, what if the buried carbon could cause problems?! Do we know our geology well enough to be sure the carbon we bury will stay put?

New research now sets that fear aside. The team led by the University of Manchester has shown through their study that for millions of years carbon dioxide has been stored safely and naturally in underground water in gas fields saturated with the greenhouse gas.

Naturally-occurring carbon dioxide either dissolves in underground water (like Coke) or it reacts with minerals in rock to form new carbonate minerals, essentially locking away the carbon dioxide underground. While much of this has been studied by simulation using computer models, the new study measured the ratios of the stable isotopes of carbon dioxide and noble gases like helium and neon in nine gas fields in North America, China and Europe. These gas fields were naturally filled with carbon dioxide thousands or millions of years ago.

They found that underground water is the major carbon sink and has stayed stable for millions of years.

Of course, one study is no guarantee. And there are other aspects to CCS.

Vaclav Smil, an energy expert at the University of Manitoba, has estimated that capturing and burying just 10 percent of the carbon dioxide emitted over a year from coal-fire plants at current rates would require moving volumes of compressed carbon dioxide greater than the total annual flow of oil worldwide. The economy of scale and the costs are prohibiting.

Retrofitting old plants for CCS would mean laying pipes to carry the gas to nearest aquifers. For new plants the dilemma is whether to build the plant over aquifers or near the fuel source? Either way it spells more costs over pipes, transmission lines, etc. Money which could well be spent on renewables.

But coal is what is available in plenty (relatively), be it in India, China or the US. So how can we simply lump it?? Leave it all to the free market?