02 Oct 2020 16:58 IST

New tech strengthens the arsenal to tackle greenhouse gases

The focus has changed from merely cutting carbon dioxide production to deploying the gas usefully

The war is on. And you’re invited to join. Picking a weapon is somewhat easier, now that the arsenal is growing. Yes, we are still on the subject of carbon dioxide. The dreaded greenhouse gas is challenging our wits to fight it but, by the looks of it, mankind will emerge the winner.

While the war on CO2 is still raging as before, the approach has changed slightly. Earlier, the focus was to stop CO2 production. This was easier said than done, because practically everything we do in our present way of life, leads to the generation of CO2. Despite renewable energy making rapid strides, a lot of electricity still comes from burning coal; and transportation almost entirely happens by burning fossil fuels. When you mine a mineral or build a building, you throw up some more CO2.

Slowly, therefore, the focus is diffusing, moving on to another point. If reducing CO2 is so difficult as to be almost impossible, why not prevent the gas from taking up residence up in the atmosphere and creating global warming? Thus came the idea of ‘carbon capture and sequestration’. You just grab the gas from the chimneys of power plants and bury it. This would, of course, call for burying space, which is only available in disused mines or exhausted oil and gas wells.

Leveraging the possibilities

So, if production of CO2 is next to impossible and burying it permanently is difficult and costly, then why not make use of the gas? This is sort of the ‘third stage’ in the war against carbon dioxide, and it is here that the potential of a large arsenal comes in.

You can make good use of CO2 — it is technically feasible. Here is an indicative (though not comprehensive) list of uses carbon dioxide may be put to: a) in oil wells, for enhanced oil production, where the gas goes underground and pushes the oil out; (b) as fuels, like methane; (c) as methanol, which can be either mixed with a fuel (like petrol) or converted into an engine-powering fuel (such as dimethyl ether, or DME); (d) as chemicals, a whole host of them; (e) as a raw material for making building materials, such as concrete; (f) to grow algae, which then can be used to produce fuels or chemicals; (g) as an input material in food and beverage processing industry; (f) to produce urea... The list goes on.

Today, a young person seeking new opportunities would be well advised to pick one of these areas for a career. There is little doubt that all of these uses will be mainstreamed—or else, the world is sure to be warmed to death.

Conversion to fuels

These uses of CO2 throw up innumerable opportunities for engagement. For instance, take CO2-to-fuels. You will get a fuel if you react hydrogen with carbon dioxide. Now, one should understand that the carbon dioxide molecule is one of the most stable molecules in the universe. It is not easy to coax the carbon in CO2 to kick out oxygen and take up hydrogen for partner, instead. This (reduction reaction) can happen only in the presence of a catalyst (which are chemicals that make a reaction happen but do not participate in it.) These catalysts today are very expensive and often unstable, and the process of CO2-hydrogen reaction is energy-intensive in itself.

So, worldwide, a hunt is on for the right catalyst. Every day you read about some scientist who has discovered a new catalyst but the truth is, the right catalyst is yet to be found. As such, there are very few CO2-to-fuel plants in the world.

A recent report of the International Energy Agency (IEA) noted that the CO2-to-fuels technology is the most potent weapon to fight the greenhouse gas.

What are we seeing here? We are at the cusp of the emergence of a completely new industry, where no country has a lead over the others. In some decades, even oil could be pushed to the margins, and fuels made with CO2may rule the roost.

Use in building materials, plastics

Take another example of carbon dioxide use: building materials. Today, some firms make concrete using the gas. This process uses CO2 in the place of water to cure concrete. In this process, the gas is sort of permanently trapped. Construction aggregates (small particulates used in building materials) can be produced by reacting CO2with waste materials from power plants or industrial processes. Among these are iron slag and coal fly ash, which would otherwise be stockpiled or stored in landfill. Producing building materials from waste and carbon dioxide can be competitive as it offsets the cost associated with conventional waste disposal.

Yet another example: making polymers (plastics). Polymer processes with CO2 can be competitive. An IEA report mentions some claims that certain types of polymers made with CO2 could be 15-30 per cent cheaper than those made with fossil fuels.

So, you see the semantic shift from ‘stamp out carbon dioxide production’ to ‘make use of carbon dioxide’? In this nuance lies the future. The world is moving into a low-carbon economy, where CO2 is likely to be a useful raw material. The IEA has described this as ‘a new dawn for a vital technology era’. This doesn’t mean that we should merrily go on producing the gas. The war is two-pronged — reduce CO2 generation and use whatever you produce, taking care not to let it into the atmosphere.

Here are some numbers to illustrate how seriously the world is looking at CO2 use. Commercial interest in carbon capture, utilisation and storage (CCUS) has been going up. The use is greater in the oil industry — to push the oil out from under the ground — and to make fertilisers, but reflects the general direction of global thinking. The IEA says that more than 30 commercial CCUS facilities have been announced globally in the last three years. And projects now nearing a final investment decision represent an estimated potential investment of around $27 billion – more than double the investment planned in 2017. “This portfolio of projects is increasingly diverse and would double the amount of CO2 captured globally,” says the IEA.

That should give us all a glimpse of a potential low-carbon future.

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