Can Electrofuels and Electrosugars Save the Day?
Jim Lane (Biofuels Digest) Is the ultimate industrial fuel system going to be based on electricity, waste CO2 and brackish water – to return society to the days of energy abundance? It will take a mighty production microorganism, but R&D is well underway and a path is becoming clearer.
…One of the reasons to pay attention is that the use of waste CO2 is a component in what you might call biofuels’ Holy Grail. That could be described as a technology that uses a modified production microorganism to directly create targeted molecules using only brackish or saline water, waste CO2 and electricity.
The electrofuels and their promise It’s an end-goal of ARPA-E’s Electrofuels project, which is scheduled to complete its first phase by years end.
… Electrofuels bypass photosynthesis altogether by utilizing microorganisms that are self-reliant and don’t need solar energy to grow or produce biofuels. These microorganisms can directly use energy from electricity and chemical compounds like hydrogen to produce liquid fuels from carbon dioxide (CO2).”
In all, 14 Electrofuel projects are expected to complete this year under their ARPA-E grants. But work continues outside of ARPA-E, too.
A production microorganism that uses waste CO2, saline water and electricity is yet to be found. It is not entirely different from the class of organisms under development by Joule, Proterro and others – excepting that those companies use photosynthesis, and Proterro’s microorganism likes freshwater.
But Joule’s and Proterro’s goals are universally admired — even if they are very early in their development — for they aim to make, respectively, renewable fuels & chemicals, and low-cost sugars. Sapphire Energy is expecting to use waste CO2 and brackish water, as well — to make algae, from which fuels can be recovered. So, there’s a class of technologies that are heading very much in this direction.
Sources of feedstock? It may well be that an ideal system would place a production microorganism in close proximity to a power generation station that uses gas or coal. Those stations produce electricity, of course — but also residues of immense interest in the form of waste CO2, process heat and steam and water (used as coolant).
Even a super-advanced power plant will produce 1,000 pounds of CO2 per megawatt-hour – as much as 25 million tonnes of CO2 per year. To put this in context — using a conventional algae production process, that’s enough CO2, onsite, to produce more than 1 billion gallons of fuel.
We can hear the “tut-tut” already: “but natural gas is not a renewable resource, it is not a renewable fuel.” To which we would point out that existing biorefineries already use large amounts of non-renewable electric power, and use gas or coal to generate own process heat. Moreover, the goal of the renewable fuels movement is to reduce the overall carbon footprint … READ MORE