Beware of CO2-Recycling Glorification!

Nature masterly recycles CO2 in photosynthesis by using solar energy to dissociate the oxygen from the Carbon and assemble it with water and Group IV-VII metalloids of the 2nd & 3rd Period into biomass under storage of transformation energy. And at the end of life-cycle Nature decomposes ceased matter into CO2, water and energy. Under aerobic conditions in the form of temperature or anaerobically as chemical energy in the form of Methane. The latter we all know as 80-98% constituent of Natural Gas. It survived over eons from the decomposition of Paleozoic biomass because Methane is the most stable Hydrocarbon compound. Because 55% of its chemical energy content is contributed by its Hydrogen Atoms, it burns cleaner than any other common hydrocarbon fuel having lower Hydrogen to Carbon ratios. So only 45% of its energy release generates CO2, 55% just react into water steam.

Since German politics decided the nuclear phase-out major nuclear industry stakeholders were compensated by the meanwhile increasingly popular Power-to-Gas agenda already successfully demonstrated in several pilot installations and different configurations. Enticed by increasing negative electricity regime in grids of significant wind and photovoltaic electricity as well as long haul transmission bottlenecks between National Feed-In Tariff profiteering renewable energy installations and the locations of actual demand Power-to-Gas seemed the perfect solution for Germany. But is it really the case for economically less privileged countries and regions? Anyways in the interest of German businesses Power-to-Gas recently gets promoted as the solution for Carbon (dioxide) recycling: Add a Power-to-Gas electrolysis for any CO2 that could be captured and pump synthetic Methane into the Natural Gas Grid (if locally existing) . . . .

One Megawatt electricity from Methane requires about 250 cubic meters of Natural Gas synthetically producible of ~100kg Hydrogen plus half a tonne CO2. If electrolysis can meet arm‘s length prices of today‘s refinery Hydrogen Synthetic Methane from CO2 Recycling would cost about 5 times US-Henry Hub, 3 times Russian pipeline or 2 times Asian Liquid Natural Gas price. So the cost of Capturing CO2 for re-Use would be ~U$500 per tonne provided electrolysis Hydrogen was producible at arms’ length with refinery Hydrogen. One tonne CO2 originates from 273kg Carbon. So CO2 Recycling by Power-to-Gas costs U$1,800 per tonne of primary Carbon. At Russian Gas prices the tonne of fossil Carbon costs 1/3 thereof. These economics do not suggest continuing to do more of the same Carbon burning into CO2. Nevertheless Europe dominated by German interests is currently subsidizing this Green Energy Business Model as most promising solution towards a so called Carbon Neutrality. But compared to Carbon Circularity this model of linear Carbon squandering with add-on reparation appears like a hoax.

Preventing Carbon transformation into CO2 in the first place by Recovering Carbon from the decomposition gases of carbonaceous matter in contrary can break even with fossil Carbon at U$30 per barrel crude oil or U$0.16 per cubic meter Natural Gas ex Henry Hub. In order to mitigate CO2 emissions the existing linear Carbon Eco-System needs to be changed to a Circular Carbon Eco-System. Instead of recovering energy decoupled from demand from available Carbon the latter should rather be consumed for Hydrogen release from water only. The transformation energy required for that is just one seventh of electrolysis. And burning the same amount of Carbon can deliver a quarter of the electricity which can be generated by a Fuel Cell off the Hydrogen mobilized by Carbon-Steam Reforming. Assuming 30% idling losses of solid and heavy fossil fuel boilers today, an on demand Hydrogen Energy Economy nourished by Carbon Circularity could increase today‘s Carbon Efficiency by factor 3.5! At one third photovoltaic plus wind energy contribution the total Carbon demand could be reduced to Recyclable Terrestrial Carbon from derbies not useful for agricultural composting at no extra cost to people. Neither for treating their waste, nor for mitigation of atmospheric Carbon Stock building. At such point real Carbon Neutrality could be reached.

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