In the 70’s, smog was much worse than today, but the invention and implementation of the auto catalytic converter quickly solved the problem. We need a similar “carbon scrubbing” invention to fit in gas burning power plants.
One of the good things about being old and retired is that I remember how things used to be…and I can tell you that smog in the 60s and 70s were terrible (litter was bad too but that’s another story). I ran a collegiate cross country race in Los Angeles in 1973 and practically collapsed after, as though I’d smoked a few packs of cigarettes (um…I knew the feeling from some irrational experimentation). At the time, I remember paying about $0.25 per gallon for gasoline (this was right before the Arab Oil Embargo that increased prices to about $0.60 per gallon). It was not uncommon for the foreign cars to get 50 mpg in those days, since gas was leaded and came out of the tailpipe untreated. All that changed (largely for the better) when the catalytic converter (which had been patented in 1956 by French Engineer Eugene Houdry) became an EPA requirement in 1975, while the air magically began to clear. This seems like quite a moment in history now, and begs the question “who will invent the “Catalytic Converter” of the Global Warming Age?” (Palucka, Castaignede, Csere, Roberts, Carter, et al, n.d.)
The catalytic converter costs about $500, and ironically converts hydrocarbons to water and CO2, the major tailpipe pollutant of today. For many years, it was the bane of automobile mechanics, as it was not synched with the old carburetors, which negatively affected engine performance. In effect, the catalytic converter cost car owners a great deal more in automobile first-cost and fuel economy, although these costs were not immediately understood. The car went from this relatively simple thing that was easy to fix yourself and cost little to run, to a more expensive, complex thing requiring more sophisticated diagnostics while getting lower gas mileage (some of this was due to lead removal, reformulated gas, exhaust recirculation and other smog controls). Looking back, it’s rather amazing how quickly we adapted to these changes, were willing to pay for them without rebellion, and how rapidly the smog problem went away.
Now let’s move forward to today, when CO2 desperately needs to be scrubbed from auto tailpipes and natural gas burning power plants (assuming that these technologies provide the flexibility and transition necessary for an all-electric and renewable future). It turns out that since around 20 lbs of CO2 are produced from 1 gallon of gasoline (since the Carbon combines with atmospheric Oxygen), it’s impractical to collect CO2 from tailpipes and more practical to collect the Carbon only. There are several competing candidates for this technology at present:
1) Hyperbranched Aminosilica or HAS. Although not conducive to placing in auto tailpipes (due to the large amounts of CO2 that would need to be periodically removed), this may be a great technology for natural gas burning power plants, as it removes CO2, stores it in silica particles (think sand) and is able to release this CO2 as a kind of plant fertilizer. (Hicks,Drese,Fauth,Gray,Qi,et al, 2008)
2) The Allam Cycle natural gas burning system (named after inventor Rodney Allam) burns natural gas with pure oxygen at high temperatures, allowing the process to create liquid CO2 which is then sequestered underground. (Yellen, 2020)
3) CO2ube fits onto your tailpipe, costs $60, and needs to be replaced every few months. It reduces CO2 emissions by about 10%. Funding levels for this device were not met, and it’s production was abandoned. Because of all that oxygen potentially combining with carbon emissions, a device that sequesters Carbon prior to release is the most practical, and even that would have to be emptied often. Most scientists believe that for this reason, Carbon removal at the natural gas burning plant, in combination with electric or hydrogen burning cars, is the most practical solution. (Lynch, 2015)
Simply put, the volume and weight of CO2 gases that the internal combustion engine creates is a far more significant challenge than the removal of the less abundant (but more toxic) hydrocarbons that were removed by the catalytic converter. This volume makes CO2 removal at the auto tailpipe downright impractical, while removal at the natural gas burning plant would require a transport system (most likely a liquefied CO2 gas pipeline) to direct the waste to underground storage or plant utilization.
A similar challenge exists for the burning of biofuels but is often not discussed, since biofuels are considered to be “net carbon neutral” (since they utilize about as much carbon in growing as they release in burning) but then this creates the logical sequitur “wouldn’t biofuels be even better if their carbons released from burning were captured and sequestered” This, and other biofuel questions can perhaps be resolved another day.