Clean Tech

The ‘solar moment’ in carbon

M. Ramesh | Updated on: Jan 09, 2022

Chemicals from CO 2 Algal production at the Hooge Maey landfill site near Antwerp, Belgium M Ramesh

If the 2010-2020 decade was one in which solar got mainstreamed, 2020-2030 will be the decade of CO2-to-fuels, says M Ramesh

It was not long ago that solar power was considered way too expensive for mainstream use. The earliest commercial solar tariffs were around ₹18 a kWhr. And then, relentless efforts brought the prices down. Today, any tariff of around ₹3 is considered remunerative.

All this happened in a decade.

Now, there is another industry that seems to be at the head of a similar trajectory. It is meant to solve the same problem, as solar — beat climate change.

Parameters such as technological challenges, costs and ecosystem seem to be just where solar was around 2008-2009. And, like solar, this industry has potential for creation of a great economic value addition.

The whole game revolving around conversion of Carbon dioxide (CO2) into fuels and chemicals is still being played out in the labs, but has all the makings of an emerging industry.

In a sense, this industry is more exciting than solar because, while solar was all about bringing down costs by scaling up cell production and improving energy conversion efficiency, the ‘Carbon dioxide industry’ just starts with the dreaded greenhouse gas, but branches off into multiple promising pathways.

Start with CO2, you can make gaseous fuels like methane and ethane, intermediate hydrocarbons like methanol and ethanol (which could be further processed to engine fuels such as Di-Methyl Ether or DME) or if CO2 is fed to bacteria or algae in suitable form, a myriad of chemicals such as Omega 3 fatty acids.

Alongside, there are efforts to make several products using CO2, a good example of which is in making concrete, where the gas is used as a replacement to water for curing the concrete.

An interesting point to note is that research is happening across the globe in each of these possibilities so intensely that something has to give way soon.

Given that this fledgling industry is cruising down the runway for a take-off, a la solar, let us take a look at how things are at the moment. In 2019, the world emitted 44 billion tonnes of Carbon dioxide. It is safe to assume that a little more than half of the emissions are absorbed by the oceans (which is bad, because it makes the waters acidic) and by land (which is good).

Roughly 45 per cent of the emissions migrate to the upper atmosphere, become a heat shield and cause the world to warm, with all the deleterious effects.

Converting CO2 into fuels

Today, there are two major uses of CO2 — in the crude oil industry, where the gas is pumped into the wells so as to push the oil up, (a process called ‘enhanced oil recovery’) and to make fertilisers (urea). By far, these two are the largest uses of the gas.

About 230 million tonnes of CO2 is used up this way — a far, far cry from the emissions let out into the atmosphere, according to the International Energy Agency. Hence, experts stress that the emergence of a CO2 user industry is not a solution to the emissions problem by itself, but it will help. There is a continued need to limit emissions and permanently how much so ever possible. But there is a growing role for the use of the gas too.

As things stand today, efforts to convert the gas into fuels — which has the best chance of neutralising CO2 — seem to be ahead in the game.

There are two challenges in this. First is Hydrogen. Hydrogen is needed to split Carbon and Oxygen in CO2 — called a ‘reduction reaction’. This Hydrogen needs to be produced both cheap and green, because if the production of Hydrogen itself will produce Carbon dioxide, it will defeat the very purpose of CO2 use.

Today, efforts are on to produce Hydrogen by splitting water, using electricity from renewable sources for that purpose. Commercial production of fuels from CO2 is possible where green Hydrogen is produced cheap. The George Olah plant in Iceland is an example of where it happens — the plant produces methanol, using 5,600 tonnes of CO2 a year.

The second challenge in CO2-to-fuels is finding a suitable catalyst. Catalysts are chemicals that do not participate in a chemical reaction — they are not among the reactants — but their presence makes the chemical reaction happen. Without catalysts, it is not possible to separate Carbon and Oxygen in CO2. The known catalysts are not good enough — they are expensive, some times toxic, and not quite stable, which means the reaction would need to be paused periodically for the catalysts to regenerate themselves.

Accordingly, the focus of global research today is on finding better catalysts. Notably, this is one of the areas where India is not lagging anybody because nobody has gone much distance from the starting line. A team of scientists at the Tata Institute of Fundamental Research, headed by Prof Vivek Polshettiwar, has come up with three catalysts — nano gold, nano silica and nano solid acids. From the industry side, engineering major L&T has tied up with the country’s largest power generator, NTPC, to work on CO2 to fuels.

Alongside, a the team led by Dr T Raja of the Pune-based National Chemical Laboratory (CSIR-NCL), has developed a method of producing DME from methanol. And, a team headed by Prof Avinash Kumar Agarwal of IIT-Kanpur is working on developing an internal combustion engine that can use DME as fuel. Only, all these efforts are happening in separate silos.

Once the world cracks the catalyst problem and is able to produce green, cheap Hydrogen, a big industry is set to emerge.

From villain to friend

So much about fuels. Coming to chemicals from CO2, there are, again, several interesting pathways. For instance, CO2 can be used in production of polymers. But the focus of research seems to be more on the bio-route, where the gas is used to enhance the growth of algae, whereupon the algae (root-less plants) can be used to produce a bunch of useful products.

While international institutions such as the National Renewable Energy Laboratory, US, are doing cutting-edge research, here again, substantial work is being done in India. Prof Ramakrishna Sen of IIT-Kharagpur, for instance, is working on using flue gases from power plants to grow algae; Dr Sanjeev Prajapati of IIT-Roorkee wants to grow algae using reject water from reverse osmosis plants in industries. Both these academics say they are seeing success in their methods.

CO2-to-chemicals, especially through the bio-route, is less of a CO2 mitigation effort and more one of making products. However, for a world in a climate crisis, any little helps.

The signals are unmistakable: if the 2010-2020 decade was one in which solar got mainstreamed, 2020-2030 will be the decade of CO2-to-fuels, though the curve could be different, because the growth of the industry could be faster towards the end of the decade. Today, CO2 is a headache; by 2030, it would look a lot more like a friend.

Published on October 06, 2020
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