Isn’t There Something We Can Do With All That CO2?

(3BL Media/Justmeans) - There can be no question that our energy supply is undergoing profound changes, driven first by concerns over peak oil that have been superseded by concerns over greenhouse gas emissions. Renewable supply has surged to the point where the idea of a future entirely free of fossil fuels now seems possible. Last year in the U.S., non-hydro renewables contributed more than hydro for the first time ever, with the total expected to exceed 14% of all electric generation in 2016. While that is hardly the lion’s share, it can no longer be described as the “tiny fraction” it once was.

Electric cars are still a tiny fraction, and no one is expecting gasoline or diesel to evaporate from the scene anytime soon. But on the power generation front, people are having existential conversations about the future of coal.

The dirtiest of all fossil fuels, coal has been targeted from the outset, the greenhouse gas issue only adding to previous concerns about mine safety, acid rain, mercury, mountain top removal, and more. But there is still a lot of it around and, because these concerns were never properly priced into it, it is still cheap.

Here in the US, coal consumption grew strongly from the 1950’s until it began to decline in 2007. The industry prevailed upon the government to invest in Carbon Capture and Storage (CCS), which would extract some portion of the CO2 from an exhaust stream, pressurize and liquefy, and then inject it underground. This was the premise behind FutureGen, which had apparently come back from the dead last year, only to be shut down again when the DOE withdrew funding. The technology is expensive to build, extracts a significant energy penalty in parasitic losses, and is unproven from a long-term environmental impact perspective.

The story may not yet be over. Given the continued commitment to coal burning in China and India, and their growing concern over emissions, it is possible that funding for this technology might pick up again. In the meantime, though, other approaches continue to emerge.

For starters, an ARPA-E project called IMPACCT is looking at additional ways to extract and sequester carbon. One method that has been demonstrated is an inertial CO2 extraction system that uses a “supersonic cyclone” to extract the CO2 and freeze it in a way that is more efficient than previous CCS processes.

But perhaps more interesting is the whole new field of carbon capture and utilization, where the CO2 is not just extracted and disposed of, but actually utilized in some useful way. The first example of this was in enhanced oil recovery (EOR) which pumped waste CO2 underground to pressurize an oilfield making it possible to extract a higher percentage of the oil compared to traditional pumping methods. This provided immediate financial returns that could be used to justify investments in sequestration. But if the ultimate goal is to reduce carbon emissions, in a world that is already talking about “leaving fossil fuels in the ground,” the idea of using CO2 for EOR quickly loses its luster.

Here are some newer approaches that actually use the CO2 molecule as a raw material for a chemical process from which useful products can be made.

In Germany, Bayer Materials Science has developed a process to recycle carbon by taking carbon dioxide exhaust gas from a power plant or a chemical plant and using it to produce polyether carbonate polyols, long chain polymers from which polyurethane foam can be made. The company is building a pilot plant that will produce 5,000 tons of the material per year that will be used for mattresses and furniture upholstery. The process, based on a life-cycle assessment, will have a 15-20% smaller carbon footprint than the process currently used for the material. This is due to the substitution of petrochemical feedstock which is offset by the CO2. According to Karsten Malsch, VP of Bayer’s Polyurethane division, the market potential could be one million ton range. While that’s a drop in the bucket relative to the amount of carbon being emitted today, it could be the beginning of an important trend.

Indeed, researchers at London’s Imperial College are deriving a similar polycarbonate polyol molecule from CO2. Their spin-off company, Econic Technologies is offering a replacement for polycarbonate, an engineering plastic material often used in plexiglass applications. They are also making polypropylene carbonate, a material suitable for food packaging and drink bottles.

If the CO2 is embedded into some kind of plastic, that is not the same as long-term sequestration. But if it keeps that carbon out of the atmosphere for even another twenty to thirty years that could be beneficial, especially if emissions are significantly lower then than they are now, which hopefully they will be.

Perhaps the biggest news of all came out just last week came from Connecticut-based Fuel Cell Energy, who have developed a fuel-cell-based carbon capture solution that can be applied to large scale power plants. In essence, this solution will use the exhaust gas as a fuel. The process, which is based on the company’s carbonate fuel cell technology, falls within the EPA’s CCS cost target, is tolerant of the contaminants found in flue gas and can also remediate NOx, a key contributor to acid rain in the process. Unlike conventional CCS approaches which can drain as much as 20% of a powerplant’s output, a fuel cell solution, will actually produce additional power, as much as 80% more, according to a press release. The technology can also be used to extract CO2 from natural gas power plants, making them essentially carbon-free.

Image credit: Mick Tursky: Flickr Creative Commons