09 Sep 2020 21:01 IST

Leveraging tech to harness polluting carbon dioxide for fuel

Various technologies are being experimented with to put this greenhouse gas to productive use

Coal is India’s energy mainstay; we have an abundance of the black gold under our soil — some 320 billion tonnes or so. And we’ve been taking out half-a-billion tonne every year. But we are expected to toss the shovels away, because when you burn carbon you produce carbon dioxide, a deadly greenhouse gas and mankind’s enemy number one.

So, we need to look to the wind, sun and the rivers for energy but getting them to produce enough to satisfy all our needs is asking for the moon.

 

But wait, we needn’t despair. Technology might just be bringing in a solution that will enable us Indians to burn coal and yet not produce the global-warming CO2. If we can be clever enough to invent a use, or several uses of CO2, we would not only not want to stop producing the gas, but also be encouraged to produce more of it.

All this is the background to introduce the fascinating area of CO2 to fuels.

There are several ways of making use of CO2. Let us look at a few of them, one by one.

Enhanced oil recovery

The first and the most basic one is to capture it all and put it in oil or gas fields, if there are any nearby, so as to use the CO2 to ‘push’ the oil or gas up to the ground — or as an instrument of ‘enhanced oil recovery’. The problem, obviously, is you can’t do this if there is no oil or gas field in the neighbourhood.

The second way is to convert CO2 to fuels (and, hence or otherwise, other useful products). This has been known to mankind for long. On the face of it, it looks absurdly simple. You put CO2 and hydrogen in a box and they will behave like a newly-married couple.

The offspring is methane, which is a gas than can be burnt for energy. You can easily make methanol, a liquid fuel, from methane, and put the stuff in your car’s petrol tanks. But the problem is, where to get hydrogen from and that too, cheap? There are many ways of doing it, but they are all either costly or carbon-emitting, usually both.

    The third approach is to convert the CO2 into acetates and feed it to water plants called algae or some type of bacteria. These bio-organisms will then eat all the acetates, grow fat and produce a number of interesting products, such as Omega-3. Here again, the problem is to convert CO2 into some kind of stuff, like the acetates, that the bio-organisms can feed on, economically.

      No endless subsidy

      Yet another way is to just gasify the coal in-situ (which means ‘right where it is’), rather than take the coal out of the ground in the first place. When you gasify coal, you get a gas called ‘syn gas’, which can then be used to produce a variety of things, like, fertilisers.

        And the list goes on. There could be many, many more such approaches. But one common challenge that all of these have been facing is: economics. You can’t keep endlessly subsidising these — they have to pay for themselves.

        The good news is, technological advances in each of these areas is showing promise. Even better news, for us Indians is, India is not lagging in these, because the start-line is the same for everyone. Here is an opportunity for India to get ahead of others in the game.

        Things are happening. Indian Oil Corporation, for instance, has been experimenting with the ‘bio route’ for using CO2. You see, their refineries also emit a lot of the gas and that is a problem. Hence the effort. Some time back, the Director of Research and Development at IOC told this writer that he was confident that his team would crack the technology, whereupon they would not only be producing in-demand products from CO2, but also licensing the technology to others.

        Making methanol

        Another example. As recently as ten days ago, India’s iconic engineering company, L&T, got into an agreement with NTPC to put up a pilot project for collecting CO2 from coal power plants and making methanol from it. The idea is, to get the hydrogen required for the process by splitting water using solar power. Clean! L&T is excited about it. Of course, it doesn’t have the entire technology, but is doing what it is good at — assembling partners with the know-how. Sooner or later, they are bound to crack the tech barrier. It could be very rewarding because CO2 from a 500 MW coal power plant can be used to make enough methanol of the value of ₹6,000 crore. A simple fact of life is, technology will come up where it has the backing of commerce.

        And, one more example. Some of you may have heard of the Talcher project — if you haven’t please do read up on it. With technology from a US-based multinational called Air Products, a consortium of Indian government-owned companies is attempting a $2 billion project to gasify coal in-situ to make syn gas and then produce urea from syn gas. This is being done in an old and moribund fertiliser plant of the sick government company, Fertiliser Corporation of India. After some starting trouble, the project is getting off the ground.

        You see the point? CO2 technologies are at the edge of the runway, inclining for take-off. Some of them may overshoot the runway and end up below the cliff, but others would indeed take to the skies.

        That is what India is waiting for, because then you can use coal and also not contribute to global warming. That is having the cake and eating it too.

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