A Smart, Faster Path to Zero Lifecycle Emission: Advances from the EU in Direct Carbon Capture from Air
by Jim Lane (Biofuels Digest) … The most scalable solution is liquid fuels that use water, captured CO2 and renewable electricity.
Thinkers have been coming around to the realization that this might be the most sustainable path, notwithstanding the joys of electric vehicles. This article by B. Zhao from Energy Policy typifies that New Thinking.
Why will the dominant alternative transportation fuels be liquid fuels, not electricity or hydrogen” Energy Policy Vol108, September 2017, Pages 712-714.
And Bill Gates stated recently that a “process that uses sunlight to produce hydrogen, oxygen, and carbon” has a potential he calls “Magical. With liquids you don’t have the intermittency problem batteries. You can put the liquid into a big tank and burn it whenever you want. If we can improve the efficiency of this process, we may produce ample clean fuel for the vehicles of tomorrow.”
Solar fuels? They’ve been much thought about, and occasionally big chunks of work have been funded privately or publicly. If we can convert solar energy directly via a photovoltaic route we can make use of about ± 20% solar energy capture as the basis for liquid solar ”fuels instead of first producing biomass with ± 1-2% solar energy capture using plants. We wrote about this technological tip of the spear recently, here.
ANTECY has been working on this route since 2010, and reports now that “We have now come to the conclusion that it is technically and economically feasible, making use of electrolysis to produce hydrogen from solar (or wind, hydroelectric or geothermal) energy and converting the hydrogen produced with clean and concentrated carbon dioxide to methanol or any other (preferably) liquid hydrocarbon.
Paul O’Connor and his ANTECY team report that “economically, this route becomes feasible when the cost of renewable electricity drops to about US$ 3 cents/KwH.”
O’Connor reports: “The technology to do so is already available and in fact state-of-the art except for the step to economically harvest carbon dioxide (and water) directly from the air. Direct Air Capture (DAC) of carbon dioxide will be necessary as in many cases no secure carbon dioxide point sources are present or will be present in the future at the locations where the lowest cost electricity (to produce Hydrogen) is available. Furthermore it may be prudent not to rely too much on carbon dioxide point sources of fossil origin to produce zero carbon emissions fuels.”
Direct Air Capture is no small thing. The problem with CO2 concentration is that it is too high to support a cool climate, but too low to be easily Hoovered from the sky. The concentration we are worried over is 400ppm, that’s 400 parts per million. That means you have to capture 2500 tons of air for every ton of carbon dioxide — and right there, that’s the reason we have left the job of capturing carbon to plants — not industrial plants, just the garden kind.
Direct Air Capture Technology
And where are we with Direct Air Capture?
You may have read recently that Climeworks has opened its first small commercial plant near Zurich, and will capture around 900 tons of CO2 per year. A great step but a tiny one — it would take 25 million of these to capture the world’s annual CO2 emissions, the inventors say.
But there are some avoided negatives, too. For example, the difficulties and costs of changing to mass-scale battery electrical vehicles, the infrastructure cost. Plus, batteries have inefficiency problems too. It has been claimed elsewhere — and Michael Tamor, a Henry Ford Technical Fellow at Ford, ruminated on this topic at the recent DOE Bioeconomy event in Washington — that at least double the electrical power capacity will be required to be able to charge all battery electrical vehicles. Also the recycling of batteries and its LCA effects remains an issue.
In the end, here’s the great advantage, and it’s infrastructure. With batteries, you have to rebuild the fleet, rebuild the energy delivery system, and rebuild the grid. Fail in any of those and you’ve failed to change the carbon picture. Each of them is massive — together, it’s the biggest industrial transformation ever attempted.
With liquid fuels, you have just the one transition, and that’s the replacement of the energy supply, so long as drop-ins are used. And there’s gradualism — there’s a transition to better energy supply today — and possibly to fuel cells down the line where you get electric motor efficiencies added to the mix. READ MORE Abstract (Energy Policy)