A sweltering heatwave languishing over the American Midwest is a physical reminder of the effects of climate change. Despite the heat and frequency of ‘once-in-a-century’ or even ‘once-in-a-millennium’ weather events, we collectively continue to belch carbon dioxide into the atmosphere. Few alternatives exist in the market today and no politician will plunge their constituents into darkness to prevent something that far into the future (nor should they). Today, I’d like to talk about carbon dioxide in transportation, the possibility of synthetic fuels, and how they would contribute to energy security.
The flavor of the week may be the electrification of vehicles, but that comes with its own set of issues. The most obvious is price; electric cars, even after subsidies, are frequently $10,000-20,000 more than equivalent gasoline-powered vehicles. Low power density of batteries makes them heavy as well. It makes it impossible to power anything airborne, trucks, and even trains. On top of that, the production of electric vehicles is actually somewhat damaging to the environment, partially negating their purpose. Rare earth metals are mined in destructive ways in mostly autocratic countries. To make matters worse, the supply chain is even more fraught than that of fossil fuels. China holds the largest deposits within its borders; they are not exactly friendly to the US.
The largest stumbling block to the electric car as our solution to transportation, though, is the existing stock of gasoline and diesel vehicles. Other issues could be overcome, but there are nearly 1.5 billion internal combustion engine vehicles currently in use. Humanity is not going to collectively abandon the tens of trillions of dollars of investment that they represent. Vehicles are durable goods, replaced infrequently. We do have alternatives, though. Manmade fuel is one promising example.
Biodiesel can be used in any diesel-powered vehicle on the road. One promising avenue for creating biodiesel involves harvesting algae (something that will only become more pervasive on a warming planet). The beauty of algae is that it reproduces incredibly quickly and it uses photosynthesis. This means we’d be sucking carbon dioxide out of the atmosphere to create the fuel that will later return it to the atmosphere. It’s carbon neutral. As a bonus, the byproduct could be used as a highly nutritious feed for livestock, allowing farms to spend more resources growing food for us humans.
Wait, you may be thinking, but gasoline powers my car. It powers most ICE vehicles on the road, in fact. Not to worry: gasoline can be made out of water and air. A recent pilot on a US naval vessel demonstrated the concept. Carbon dioxide is converted to carbon monoxide and electrolysis separates the hydrogen atoms from oxygen in water. After that, something called the Fischer-Tropsch process is used to combine the hydrogen and the carbon monoxide into liquid hydrocarbons (including, but not limited to, gasoline). We could use solar or wind energy to perform electrolysis and capture and convert carbon dioxide. Combining them actually gives off energy, so that could theoretically be recaptured by the grid for immediate consumption during peak hours or some other energy storage system (hydrogen via electrolysis, perhaps?).
Another perk is that those synthetic fuels could be produced in a distributed fashion, saving transportation costs and preventing future supply chain disruptions from spiraling out of control. If we can produce the fuel where we use it, we will have a much more flexible system. The key now is driving down costs.