One way to quickly achieve near-gigatonne-scale (1 billion tonnes of CO2 removed) CDR would be to shut down the approximately 1/2 of the 300 GW of coal fired electricity generation capacity in the US and build new biomass gasification power plants with carbon capture and storage (BECCS) in its place. Such an action would eliminate over 750M tons of CO2 emissions from the coal plants each year, with the added benefit of sequestering roughly the same amount of emissions through the biomass CCS, for a net benefit of nearly 1.5B tons of CO2 -- roughly a quarter of all CO2 emissions in the US. Is such an action even feasible?
Technically, most likely. Viable biomass gasification power plants and viable CCS technologies exist today. A Department of Energy study suggests that there could be 750 billion kWh of sustainable biomass supply available by 2030, which is roughly half of the coal generation in 2013 (parastic loads from CCS might drive this supply need higher, however, which would be possible in this report's more aggressive biomass supply scenarios).
How much would it cost?
Interestingly, the US Energy Information Agency (EIA) does not even estimate biomass IGCC + CCS costs (it only estimates biomass power, and coal/natural gas power with CCS). The EIA does estimate that biomass combined cycle power costs about $8,000/kW. Assuming BECCS has the same 50% premium over conventional biomass that coal CCS has over conventional coal, this would mean a biomass power plant with CCS would cost around $12,000/kW (and would be by far the most expensive technology in the EIA's estimates). At this price, it would cost roughly $1.8T to replace half of our coal power fleet with carbon negative biomass power.
In addition to this capital cost of new plants, it would likely cost significant amounts more to build the necessary CO2 transportation and storage infrastructure, and help retrain coal workers displaced by this change. If those costs added an additional 50% to the power plant price, this would bring the total costs for this action up to roughly $3T.
Lastly, variable costs of power generation would also increase. It is difficult to predict exactly how much costs would rise, but biomass power is estimated at about $0.06/kWh. Add a 50% premium, and the $0.09/kWh energy from a BECCS plant would cost three to four times much as coal power does today. Coal is rarely a price-setting fuel, however, so it is unlikely that power prices would rise by an equal amount. Even if power bills doubled, this would amount to an extra $400B or so cost to the economy..
$3T up front and $400B annually is a lot of money, but if this plan were phased in equal installments in over 10 years, the annual cost would be roughly $500B (assuming $300B fixed +$200B in average price increases over the ten years), considerably less than then $3T or so the US spends on healthcare each year. With such low interest rates, the US could probably finance such a policy relatively cheaply.
Simply switching out coal for BECCS in the next ten years is not the most cost-effective way for the US to reduce 1.5B tons in emissions -- and also runs additional risks of many adverse unintended consequences, such as biomass supplies not being grown sustainably or causing food prices to rise, etc. (without even touching the question of whether the US should use its access to cheap financing to borrow $5T to fight climate change...).
What it does show is that if we do find ourselves in need to deploy CDR rapidly and at large scale, we can probably achieve that goal without torpedoing the economy at the same time.