In a new twist on carbon capture and storage a number of entrepreneurial companies are looking to turn the gas into a valuable feedstock, rather than simply locking it away underground. After all, carbon is a key building block for numerous products.
By Mike Scott
As a means of reducing greenhouse gas emissions, considerable investment and effort has been expended on development of carbon capture and storage (CCS) technologies – how to most effectively capture carbon dioxide and store it underground or under the sea – yet the industry is lagging behind expectations.
Perhaps it is time to start looking at carbon dioxide in a different light. A number of companies are doing just that with new ideas about ways of using the greenhouse gas as a feedstock for other materials given that, like petroleum, it contains carbon, one of the key building blocks of the chemical industry.
CO2 can be used to boost the production of depleted oil wells in a process known as enhanced oil recovery (EOR), to produce chemicals such as ammonia, urea for fertilisers and polycarbonates that can be used in paints. A small amount is also used by the food and beverage industry in applications such as carbonated drinks.
There are two main ways of sourcing the CO2 – from the air and from stationary sources such as power stations or industrial installations. Air capture is expensive and more energy-intensive than capturing concentrated CO2 from power or industrial sources, according to Kieron Stopforth, CCS analyst at Bloomberg New Energy Finance.
It would seem to make more sense to harvest the gas from more concentrated sources in industry; however, this has not stopped Richard Branson’s Virgin group from offering a $25m prize, the Virgin Earth Challenge, “for the successful commercialisation of ways of taking greenhouse gases out of the atmosphere and keeping them out with no countervailing impacts”. From 2,600 submissions, it has drawn up a shortlist of 11 projects that it thinks might be viable. While a number of these involve the production of biochar, Canada’s Carbon Engineering is a startup company focused on “engineering and commercialising technologies to capture CO2 directly from the atmosphere at industrial scale”.
Air capture requires an energy source, such as natural gas, concentrated solar power or nuclear heat, the company says, and it produces a stream of pure CO2 as its principal output. Chemical processing methods are then used to combine this CO2 with hydrogen split from water to produce carbonneutral fossil fuels. The company claims it can make gasoline, jet-fuel or diesel and emphasises that the carbon they contain is derived from the atmosphere rather than the earth’s crust.
Another finalist, Germany-based Climeworks, says the gas can be used for treatment of alkaline wastewater, as a solvent for cleaning processes, in a range of food and drinks applications – including as freeze drying, conservation and carbonation of drinks – and can increase the crop yield in greenhouses by up to 30%. Climeworks has taken an air capture approach because it says “flue gas capture systems have to deal with complications like high inlet temperatures and contaminants such as SOx and NOx, which is not the case for air capture”.
Air capture also allows CO2 emission and capturing to be decoupled in time and location, it adds. “CO2 capture does not need to take place next to the site of emission. An air capture plant can instead be constructed at a more favorable location in terms of CO2 transportation, space, costs, and other surrounding conditions.” Furthermore, the company says air capture is the only way to capture CO2 emitted by distributed sources, which make up nearly half of global CO2 emissions.
Meanwhile, Dutch company Smart Stones hopes to capture CO2 using a mineral called olivine, a form of magnesium silicate, which it claims captures 1.25 tonnes of CO2 for every tonne of rock extracted. By mining, crushing and grinding the rock, which is widely available around the world, it would be possible to capture the gas by mixing ground olivine with fertilizer. This would reduce acidity and add minerals to the soil, it says, and the mineral can also be used as a fi re extinguisher and an air filter.
While air capture methods of CO2 capture and reuse appear to be dominated by small start-up companies, those looking at flue gas reuse are operating on a quite different scale. Companies such as Bayer Material Science and RWE are looking to use what is currently regarded as a dangerous waste product to produce new products. Bayer’s Dream Production initiative aims to bring CO2-based products to market by 2015, and last year it opened a pilot facility at the company’s Leverkusen headquarters for the chemical treatment of CO2 emitted by a power plant.
“Bayer’s primary interest is to replace a portion of increasingly scarce petroleum with abundantly available CO2, thus ushering in a transformation of the raw material base from fossil to alternative resources,” the company says. There is also a limited but welcome cut in emissions, it adds. The pilot plant is producing “significant amounts” of a chemical that is one of two components used to produce polyurethane, which finds its way into products ranging from cars to building insulation to furniture and shoes.
The initiative is part-funded by Germany’s Federal Ministry for Education and Research, and the utility RWE provides the CO2 from its Niederaussem power plant. RWE is also working with biotechnology company BRAIN on a EUR 2m ($2.6m) project that aims to “convert CO2 into biomass or directly into secondary raw materials with the help of micro-organisms bred to explore innovative CO2 conversion and synthesis pathways”.
Researchers at BRAIN, after examining more than 3,000 micro-organisms have found that 29 tailor-made specialist micro-organisms, 10 of which were previously unknown, directly ‘feed’ on CO2-containing fl ue gases from lignite-fi red power stations and even grow at temperatures of 60°C. Ultimately, RWE intends to apply the fi ndings of the project to other carbonrich waste streams such as sewage and wastes from food or refining processes. Key to Bayer’s Dream Production initiative was the discovery of a suitable catalyst to enable the efficient reaction of the CO2, which is normally slow to react.
Another company putting catalyst technology to good use is US-based Novomer, a spin-off from Cornell University that aims to produce polymers and resins that can be used in products ranging from plastic packaging to adhesives and polyurethane foam. “Our products contain up to 50% CO2 by weight, which means 50% less petroleum that we need to use,” says Peter Shepard, executive vice-president of polymers at the company. “We are not doing this as a way to sequester CO2. Our focus is on using CO2 as a low-cost feedstock. “The entire plastics market is 400bn lbs. If you replaced all of that with our product, that is only 200bn lbs of CO2 While using CO2 as a feedstock is a feasible alternative to CCS, the volume of CO2 the industrial market needs is a small fraction of the amount produced by energy generators and other installations. saved, a fraction of what is emitted globally,” he added. Novomer’s business strategy assumes that it will have to pay for CO2 at market prices, but over time emitters may give it away free to avoid having to pay carbon taxes, “although we don’t need that to be competitive,” adds Shepard.
Oil prices are expected to continue to rise in the long term which means the firm’s cost-competitiveness will only improve over time, he says. The company, which is privately funded and whose backers include Dutch Chemicals group DSM, expects its first products – coatings materials – to hit the market this year. “There are many companies out there working with bio-based processes that have the aura of sustainability, but they do not have our cost advantages,” Shepard says. “All our chemistry is synthetic chemistry that is easily scaleable and easily understandable.”
Other industries too are exploring innovative production processes that consume CO2. Novacem, a cement producer named one of Bloomberg New Energy Finance’s New Energy Pioneers in 2010, uses a production process that it claims is carbon negative because the magnesium silicates it uses as a feedstock absorb CO2 to produce carbonates. “Production of 1 tonne of ordinary Portland Cement emits 800 kg of CO2 on average, whereas production of 1 tonne of Novacem cement absorbs up to 50 kg of CO2. Thus, for every tonne of Portland cement replaced by Novacem, production stage CO2 emissions are reduced by up to 850 kg,” the company says.
Given that the cement industry produces 5% of the world’s CO2, the company’s impact in cutting emissions could be considerable. It expects to start selling its product in 2014 or 2015. While using CO2 as a feedstock is a feasible alternative to CCS, the volume of CO2 the industrial market needs is a small fraction of the amount produced by energy generators and other installations, Shepard explains. “It is a step in the right direction but not the complete answer.”