Some Sighting Shots at The Costs of Capturing the CO2 Emissions from Cars and Home Heating

By Ian Page – 2021.12.28

The EU standard for fleet level passenger cars is 95gm CO2 emitted per Km (due to finagling and paying Tesla to appear to be part of the fleet the actual figure is larger)

The average UK car does 7000 miles/yr.- 11,300 km/year

Thus, the annual CO2 emission of a UK car is 11,300*95 gm, or 11.3*95 kg= 1000kg. = 1 metric ton near enough.

One ton of CO2 will optimistically cost $200 to remove = £150 pa. (And a fair amount of energy) (recent paper in Joule looking at the potential techno-economic aspects of direct air capture)

So, the average car driver should pay at least £150pa (actually more because few people drive as carefully as the companies trying to get a low figure! Also, most driving is short distances which doesn't achieve anything like these figures). US drivers with larger less efficient cars would pay well over $200 extra per year.

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The average UK natural gas consumption for space heating and water heating is equivalent to 3.2 tons of CO2 emissions per year. Which at about £150 per ton to capture it from the air is around £460.

The average UK gas charge per Kwh was 4p (now much higher 8-12p), which made the annual bill with connection charge around £480.

Thus, if the CO2 emitted was abated by direct air capture it would have doubled the consumer cost of gas. (Last year, this year probably just added about 50% to the cost to take it to a total with an abatement of around £1500.)

(The gas figures are hard to nail down as now companies are talking about a typical £2000 gas bill next year. The higher the gas price, the lower the percentage increase for abatement!)

The US has much cheaper natural gas, and thus the DAC cost would be a much larger proportion of the annual house bill.

What this tells us is what we have said before. The cheapest way of reducing CO2 is to stop burning fossils!

Another way to look at the comparison between the cost of renewables and the cost of fossils for space heating and vehicles, is to just add the actual current best estimated cost of removal of the CO2 to the cost of the fuel.

(We should note that the $200 / ton CO2 figure is the best estimate of what it WOULD cost if the existing technologies were scaled up, the current figures are much higher ($600). We should also note that various startups are aiming at $100 per ton, but this is more an aspiration than a techno economic projection).

I found this a useful way of avoiding getting mired in the politics of CO2 pricing. This is the sort of cost consumers will see to eliminate their CO2 emissions from small passenger cars and home heating with natural gas. Since renewable energy can already do the job significantly cheaper, applying the right economic cost would cause a very quick transition! 

Carbon capture at source should be cheaper for thermal electricity generation since the concentration of CO2 is so much higher (estimates of an additional 30-50% to the cost of electricity generation, less to the consumer as the about 100% UK grid surcharge is unchanged). but there ARE many diffuse sources of CO2 that only DAC can handle. Even if all concentrated sources of CO2 were captured and sequestered, there are many diffuse sources, not least humans, barbeques, animals, forest fires etc., plus the large stock of past emissions that need to be removed to get from 400 ppm to a long term 300 ppm Nature is unable to consume this past stock quickly enough if at all.

Note we have not allowed anything for storage /sequestration so all the costs will be higher.

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Energy consumption

This is estimated at 5-12 megajoules per Kg Co2 captured by the leading methods (when optimized). which is between 1.4 and 3.3 kwh. 

For a ton of CO2 captured this is about 1.4-3.3 megawatt hours.

So, for the above fossil car example, annual capture of 1 ton would require additional say 2.3 (average of estimates) megawatt hours to be generated by renewable energy (if it wasn't renewable the Co2 emitted during generation would also have to be captured consuming more energy which in turn would generate more CO2 to be captured etc.)

An efficient (tesla) EV doing the same 7000 miles per year would use about 4 kwh per mile, or 28 mwh/year just for a scale so in terms of total generation alone, the tesla not having to capture CO2 emissions would get 30 more days of travel from the amount of electricity saved by not having to capture the CO2.