Could US oil imports be replaced with a single set of facilities producing biofuels from CO2, salt water and low-cost natural gas? Subsidy free, cropland free, mandate free?
If you happen to be awakening from a four-year nap, or returning from a tour of the outer solar system, you may not have been made aware that US natural gas prices have plummeted, and are expected to remain at half the cost of petroleum, or less, for years to come.
Now, it is common knowledge that cheap natural gas can be used to generate cheap power, or that low-cost compressed natural gas that can power some specially outfitted trucks. Fewer people know that natural gas is a platform for producing ethanol – either through fermentation or catalytic conversion (typically via methanol) – and drop-in fuels using the methanol-to-gasoline method pioneered years ago by ExxonMobil are another route.
One of the more intriguing uses of natural gas is to use it to generate electric power, and then convert that electricity directly into biofuels.
Huh? What happened to biomass? What happened to renewable sugars?
Yep, there's a whole class of processing technologies that can use electricity, water and CO2 to make hydrocarbons and other molecules that can be burned for fuels – or alternatively used in green chemistry to make flavors, fragrances, fibers, solvents, lacquers, thinners, paints, cleaners and a host of other everyday products.
And in doing so, this class of technologies bypasses perhaps the most perplexing barrier to higher yields and cost competitiveness.
Which is to say, photosynthesis itself.
As ARPA-E explains, "Most biofuels are produced from plant material that is created through photosynthesis, a process that converts solar energy into stored chemical energy in plants. However, photosynthesis is an inefficient process, and the energy stored in plant material requires significant processing to produce biofuels."
