# CO2 Storage, it's possible, but what about

It is possible to store $$CO_2$$ geologically similar to natural burial. But at the rate that it needs to be buried, how do we know it is economic enough that more fossil fuels wouldn't have to be burned than what can be buried at an effective rate?

• I have serious doubts at large scale. We make more CO2 than almost anything else - many times more than all other waste put together. Much more by weight than the amounts of fuels burned - 2.8 tons per ton of high quality anthracite coal or 3 tons per ton of gas for example; fuels have value, CO2 has costs. There will be significant hardware and energy costs to managing a waste stream at that scale. My understanding is that geology that has no prior drilling is preferred - not sure there will be many places like that. Capping boreholes is problematic if to last more than a few decades. Mar 4 '20 at 22:56
• Capping an unused well is no issue. "Plugged and Abandoned" is the standard terminology. There are hundreds of thousands , if not millions , of plugged and abandoned wells in the world today. Very simply, "plugging" involves pouring a few hundred feet of cement into the well , nothing remains visible on the surface. Mar 5 '20 at 23:17

It is possible and there are several demonstration projects running. In Europe, the carbfix project quotes a price of $24.8/ton for carbon sequestration. Geothermal power is used to pump the CO2 underground, so no energy from fossil fuel is required. There are concerns about the available capacity for storage using these mechanisms, and the pumping process does trigger seismic activity (e.g. wikipedia). It is likely that carbon buried in geological formations will be sequestered more reliably and for longer that carbon which is simply absorbed by trees ... but there is no guarantee on that there will not be some leakage. Because of these concerns, and because generating electricity from sustainable sources is cheaper than burning fossil fuels and then trying to manage the pollution, the main focus of dealing with global warming should be reduction of fossil fuel use to near zero. There may well still be a significant role for carbon sequestration in dealing with some CO2 emissions which are difficult to avoid. • It's not the case that just because geothermal power is used the process is carbon-negative. For instance you have to know whether, instead of being used to store$\mathrm{CO_2}\$, the geothermal energy was used to prevent its generation, this would require less energy.