Carbon question

The Financial Express
Posted: 2008-03-18 23:53:35+05:30 IST
Updated: Mar 18, 2008 at 0015 hrs IST

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: Oil at $100-plus a barrel incentivises search for all kinds of substitutes and/or alternative oil extraction technologies. Hopefully, the government’s clearance of the Tata-Sasol coal to liquid (CTL) project—India’s first—will mean this country takes a major step in a short while towards obtaining oil by other means. CTL technologies are in fashion worldwide. China and the US, for example, have set ambitious targets. China plans to set up 28 such facilities. And the National Coal Council in the US is trying to push through CTL projects, which are expected to meet 10% of the country’s oil demand by 2025. India, as usual, has been a slow learner. The coal sector has almost exclusively focused on using subcritical pulverised coal (PC), the cheapest technology with the least risks, for the generation of power. It is only recently that we have officially woken up to technological/commercial possibilities of new combustion pathways, coal gasification systems and supercritical pulverised coal power plants.

There are, however, some persistent questions on CTL. One is on CTL technology’s big carbon footprint. Critics claim carbon emissions in CTL processes are 2.5 to 3.5 times that of conventional hydrocarbons. The Sasolburg plant had to shift its feedstock from coal to gas only recently. The other major criticism is the intensity of water use. Again, critics’ favourite piece of data is that 12-14 barrels of water are needed for every barrel of liquid fuel from coal. Bear in mind, though, that these are not insuperable problems. For instance, technologies to capture and store CTL carbon dioxide are already being developed. CTL’s critics also argue the technology will result in loss of coal for conventional uses. They buttress this thesis by pointing out that of the total 253 billion tonnes of geological coal reserves in India, only 96 billion tonnes are proven reserves (within a depth of 1,200 metres). This, runs the critique, limits the availability of coal for “new” uses. However, this is a static argument. Even if the limits of coal supply are known, new technological uses can’t be restricted if some factors, like high prices of imported oil, make such use commercially viable. The global oil economy is clearly indicating that risks need to be diversified.