Enhanced Weathering: Simple Economics?

Enhanced Rock Weathering aims to absorb atmospheric CO2 by scattering silicate dust onto agricultural or coastal lands, encouraging the formation of bicarbonate ions (HCO3-), which ultimately run off and are sequestered for thousands of years in the ocean. This data-file aims to compile some helpful statistics into the energy costs, financial costs and logistical complexities.

ERW has recently been ascribed potential to sequester 2 bn tons of CO2 per annum, with costs ranging from $60-250/ton. However, our own numbers suggest this is optimistic. The process of rock grinding and dust transportation is energy intensive and will re-release 10-30% of the CO2 captured. We estimate 4-5 tons of basalt must be scattered per net ton of CO2 sequestered. It is interesting to consider whether mining basalt should be materially cheaper than mining other bulk commodities (at c$40/ton).

The data-file contains our ‘top three charts’, our workings and our underlying notes from the technical literature..

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