MIT engineers make converting CO2 into useful products more practical

Scale and practicality of CO₂-to-products

• Several comments stress that global ethylene demand (~300 Mt/yr) would consume only ~1 Gt CO₂, tiny relative to tens of gigatons of annual emissions; synthetically made ethylene would “pile up” if treated as a primary sink.
• Many see this tech as potentially useful for the “last 10%” of emissions or as a non-fossil chemical feedstock, not a primary climate solution.
• Some note the article doesn’t quantify energy per ton of CO₂ or total cost, making overall practicality unclear.

Biological vs engineered sequestration

• Comparisons are made to trees, grasslands, and bamboo; grasslands in some climates sequester carbon more reliably than forests, especially via soil.
• Suggested “natural” strategies: timber for long-lived construction, burying biomass, using wood/fibers instead of concrete/steel.
• Others point out the scale problem: you’d need to grow and bury vast amounts of biomass for many years to offset current emissions.

Thermodynamics and energy needs

• Repeated point: “unburning” CO₂ into energy-rich molecules must require at least as much energy as was gained from burning the fuel, often more due to inefficiencies.
• Some distinguish between low-energy CO₂ capture vs high-energy conversion into fuels/chemicals.
• There’s disagreement on how binding this limit is in practice, but consensus that any large-scale removal must be powered by low-carbon energy.

Economic and policy considerations

• Discussion of chicken-and-egg economics: new processes can’t beat fossil incumbents without scale, but scale requires customers or policy support.
• Suggestions include government intervention, targeted subsidies, or marketing “premium” low-carbon products.
• Concerns raised that fossil-fuel-linked funding may serve more as greenwashing than real decarbonization.

Use of CO₂ and synthetic fuels

• CO₂ is already traded at scale, especially for enhanced oil recovery (EOR); critics say this often just enables more fossil extraction.
• Others argue that, with cheap renewables, synthesizing hydrocarbons (e-fuels) from CO₂ and water could eventually compete with drilled fuels and provide long-term, carbon-neutral energy storage.
• Efficiency of such storage is low compared to batteries/pumped hydro but might still be acceptable for niche or long-duration uses.

Materials and technical details

• The PTFE (a PFAS/Teflon) component raises environmental and regulatory concerns if scaled.
• Copper cost is questioned; replies suggest electricity and plant CAPEX, not copper, dominate costs.
• Some note similar gas-diffusion and PTFE-based electrodes are not new; this work is seen as incremental rather than revolutionary.

Carbon capture as climate strategy

• One camp calls large-scale removal via such tech fundamentally impractical and a distraction from simply not burning fossil fuels.
• Another camp sees parallel tracks: aggressively cut emissions while also developing removal/sequestration for legacy CO₂ and hard-to-abate uses.