It’s a chemical engineer’s job to chase pipe dreams.

Unlike many of their fellow engineers though, Aniruddha Sharma and Prateek Bumb have something to show for their many years of toil. The company they founded in 2009, called Carbon Clean Solutions, has created a crucial technology the world needs to reach the low carbon-emissions targets set out in the Paris climate agreement.

The proportion of renewable sources in the world’s energy supply is increasing rapidly, but not fast enough to keep global temperatures from rising 2°C above the pre-industrial average, which is when climate change reaches a critical point of no return. This is why both the United Nations and the Intergovernmental Panel on Climate Change say we need a technology that allows us to keep burning fossil fuels—even as we wean ourselves off them—without releasing all of the carbon dioxide (CO 2 ) produced.

For a long time, such technologies have focused on carbon capture and storage (CCS), where carbon emissions from, say, a coal power plant are collected and injected deep underground at great cost. In recent years, the focus has shifted in part to carbon capture and utilisation (CCU), where the emissions are turned into useful products.

Carbon Clean Solutions built a plant in Tuticorin in southern India that captures carbon dioxide from its coal-fired boiler and converts it into soda ash (a chemical cousin of the baking soda you buy in a grocery store). And, in what Sharma says is a world’s first, the commercial-scale plant set to capture 60,000 tons of CO 2 annually does it so cheaply that it did not need any government subsidies.

Building a bridge

That is indeed a remarkable achievement. Though carbon-capture technologies have been around since the 1970s, they have only been used profitably by oil companies to inject carbon dioxide into wells to remove every last drop of oil they can. More recently, companies like Covestro and LanzaTech have been slowly introducing CO 2 as a raw material, or “feedstock,” in their commercial production process for polymers and synthetic fuels, respectively, but both have relied on some form of government support.

This is why, though carbon capture is great in theory, it hasn’t gained wide commercial use. There is clearly a cost associated to spewing carbon dioxide into the atmosphere, and critics have long said that the market doesn’t price the emissions at its real value. Consider, for instance, the European carbon-trading scheme, which was set up to allow companies to trade their savings on carbon emissions with other companies who were spewing more of it than government regulations allowed. It is currently the world’s largest carbon-trading market and it only values emissions at $6 per ton of CO 2 . On the the other hand, the leading technologies available today are only able to capture CO 2 at $60 per ton—a $54 gap, at best.

Carbon Clean Solutions At the Tuticorin plant: In goes carbon dioxide, out comes soda ash.

But there’s hope. At a recent industry conference, Peter Styring of the University of Sheffield told me that the true cost of carbon emissions, measured through environmental degradation and such, is likely close to $30 per ton. And Sharma says the CCU plant, built in partnership with Tuticorin Alkali Chemicals and Fertilisers, captures emissions from coal at a cost of about $30 per ton.

“The next generation of the technology we are working on could cut the price down to $15 per ton,” he says. If the company is able to do that, Carbon Clean Solutions could push carbon-capture technologies into the mainstream.

Before Carbon Clean Solutions came along, the Tuticorin chemicals plant used to buy carbon dioxide to make its soda ash. It also bought coal to fire up its boiler. Now, instead of wasting carbon dioxide that burning coal produced, the plant is capturing it and saving the money on buying any more carbon dioxide. As a plus, the CO 2 supply is also more reliable than before.

“I am a businessman,” Ramachandran Gopalan, the managing director of the Tuticorin plant, told the BBC. “I never thought about saving the planet. I needed a reliable stream of CO 2 , and this was the best way of getting it.”

Chemical magic

So how did Sharma and Bumb do it? The duo launched the company while they were still students at the Indian Institute of Technology (IIT), Kharagpur. However, they couldn’t find investors for their company in India. So they turned to the UK government, which was willing to provide grants and special entrepreneur visas.

Since moving to London, the company has filed six patents. Its technology addresses one of the biggest current limitations of the carbon-capture industry: how to purify CO 2 out of the many types of gases released from a coal plant.

Typically, this is achieved by first treating the combustion exhaust gases from the coal plant to remove the small amounts of sulphur dioxide and nitrogen oxides (which can cause undesirable reactions in the next step). Then the remaining mixture, containing mostly nitrogen, carbon dioxide, and water, is passed through a chemical called monoethanolamine (MEA). This chemical reacts selectively with only CO 2 , and the rest of the gaseous mixture is safely released into the atmosphere. Later, the MEA-CO 2 mixture is heated, which releases nearly pure carbon dioxide to be used as a raw material.

The process works and the technology is in action at many plants around the world. But it’s expensive. There’s the material cost: Because MEA is corrosive, the reactor used to handle it has to be built from high-quality steel. Then there’s the energy cost to re-heat and recover the CO 2 .

“I never thought about saving the planet. I needed a reliable stream of CO2.”

Sharma and Bumb’s technology cuts costs at both levels. Carbon Clean Solutions has synthesised a new chemical, called CDR-Max, that does the job better than MEA. Sharma won’t reveal any more details about the company’s main product, but he says that the chemical is less corrosive—and so can work in a cheaper reactor—and requires less energy to release captured CO 2 .

An independent review by the University of Kentucky, which Sharma shared with Quartz, found that CDR-Max captures more than 90% of CO 2 from the exhaust of a coal-fired plant. Crucially, it is then able to recover the captured CO 2 using only about 30% of energy required by a typical MEA carbon-capture plant.

Scaling up ambitions

Carbon Clean Solutions says it has already sold the technology to a second company building another plant, also in India. Unlike the first small-scale plant which converted CO 2 into soda ash, this second one is likely to be using CO 2 for manufacturing fertilisers. Sharma is also in talks for a third plant, but won’t reveal details.

The 20-person company has its headquarters in London, but also has employees in India and the US. The last time it raised money was in September 2015 with Eldon Capital Management to the tune of £3.4 million (about Rs 30 crore, or $4.2 million), but Sharma says the company isn’t looking to raise any more because revenue growth has been strong.

“So far the ideas for carbon capture have mostly looked at big projects, and the risk is so high they are very expensive to finance,” Sharma told the Guardian. “We want to set up small-scale plants that de-risk the technology by making it a completely normal commercial option.”

The true test of the new technology would be to capture emissions from a large fossil-fuel power plant. Much like a drug goes from a lab to ever-increasing clinical trials before being sold on the market, a new chemical like the one Carbon Clean Solutions has developed has to go through the same process if it is to be applied at a larger scale. And just like the case of drugs, there’s a high-attrition rate as chemicals scale up from the lab to a big power plant.

Currently, the Boundary Dam project in Saskatchewan, Canada is the only large coal power plant that captures all of its emissions. But there are many others in planning-and-construction phases. If Sharma and Bumb want to make a real dent in reaching low carbon-emissions targets, they’ll have to start thinking big.