It's Hard to See Any Other Way Forward

We are going to have to accept substantially higher costs for liquid-carbon fuel.   There are some uses, such as aviation, that just don't suit alternative energy options, at least not those available today.

Why should petroleum-based fuels cost two, three, four times what they do today?   Two reasons: we need to price fossil carbon realistically to reflect the true environmental costs it imposes and we need to use that revenue to support non-fossil fuels.

There are new technologies that enable us to use surface carbon assets instead of fossil carbon to produce the gasoline and oil we need for these essential purposes.   One of them involves stripping CO2 out of the biggest carbon sink on the planet, our oceans.  The U.S. Navy has experimented with the technology as a means to create a constant supply of jet fuel for their aircraft carriers at sea.  It's also a highly efficient form of carbon capture.

Rather than going after the CO₂ directly with chemical scrubbers, they use electrochemical processes to split seawater into an acid and base stream, and the CO₂ bubbles off from the acidified water.  The two streams are recombined and returned to the ocean.  While these processes are novel, they are very similar to a number of ion exchange processes, including desalination, which are currently deployed at scale.

The Navy costed the production of jet fuel at sea.  But they neglected to include the cost of energy for the carbon capture process.  I used the PARC research to estimate it and include it in the Navy costings.  I arrived at $1.78 per litre. I was also able to calculate the cost of just the carbon capture part of the process at about $114 per tonne of CO₂.
But if we don’t insist on running these processes on an expensive ocean-going platform, the cost drops to $0.79 per litre for synfuel and $37 /tCO­₂.  The costs are rough and there are a number of caveats, but this is surprisingly low. To put it in context, the American Physical Society recently reviewed carbon capture from air, and “optimistically” costed it at about $600/tonne.

In other words, fossil fuel hydrocarbons, priced properly, are hopelessly uneconomic.   Once you strip away all the subsidies and tax deferrals, all the unlevied carbon and other environmental costs, options like seawater syncrude really come to make sense.

We'll always need to burn some hydrocarbons but, when we have abundant surface carbon resources, there is no case to be made for continuing to rely on fossil carbon.   Big Coal and Big Oil and even Big Gas won't like it but, then again, they're not exactly doing much for the future of the planet, are they.