When talking about the future of Dominion Energy in a recent TV interview, Dominion Energy Chief Executive Officer Tom Farrell mentioned carbon sequestration as an approach for reducing greenhouse gas emissions as the company moves toward a “zero net” carbon energy mix.
In the past, carbon capture and sequestration (CCS) seemed to be going nowhere. However, today, according to the Global CCS Institute, 19 large-scale commercial carbon capture and sequestration facilities are operating around the world, 10 of which are in the US. All of them are pulling carbon dioxide from the emissions of an associated factory or power plant. The trouble is that the carbon has nowhere to go, so both removing and sequestering the carbon adds major costs to electricity generation.
Once the large amounts of carbon dioxide emitted from the electricity plants have been captured, the small matter remains of where to store it. Under everyday conditions, carbon dioxide is a gas, so it takes up a huge amount of space, and it is being produced in vast quantities. An option with its own set of complications is to turn the carbon dioxide into a liquid (so that it takes up a tiny fraction as much volume) and then pump it deep underground where it, one hopes, will remain. The thought of storing it deep in the ocean has been discarded because the ocean has already acted as a CO2 sink and appears to be reaching its limit absorbing CO2 without creating great damage.
CCS technology plays only a marginal role in cutting emissions today. Each plant can cost $1 billion or more, and, so far, governments have been reluctant either to subsidize it or to put a price on carbon. Today’s 20 large-scale projects can capture approximately 40 million metric tons of carbon dioxide each year, but that is only about 1% of global emissions. Another drawback adding to the cost of CCS is that it requires considerable extra energy (some estimates say 25–40%, others 30–60%) to operate. The extra energy could almost double the cost of electricity.
Proposals for two new CCS plants, one in New Mexico and one in Puerto Rico, are being challenged. Assumptions about their stated capacity and capture rates, and their ability to sell the sequestered carbon and actually put it to use, all have been challenged. The most promising use for captured CO2 is in the process of producing more oil.