The world is quickly realizing it may need to actively pull carbon dioxide out of the atmosphere to stave off the ill effects of climate change. Scientists and engineers have proposed various techniques, but most would be extremely expensive—without generating any revenue. No one wants to foot the bill.
One method explored in the past decade might now be a step closer to becoming practical, as a result of a new computer simulation study. The process would involve pumping airborne CO2 down into methane hydrates—large deposits of icy water and methane right under the seafloor, beneath water 500 to 1,000 meters deep—where the gas would be permanently stored, or sequestered.
The incoming CO2 would push out the methane, which would be piped to the surface and burned to generate electricity, to power the sequestration operation or to bring in revenue to pay for it.
A methane hydrate is a deposit of frozen, lattice like water molecules. The loose network has many empty, molecular-size pores, or “cages,” that can trap methane molecules rising through cracks in the rock below.
The computer simulation shows that pushing out the methane with CO2 is greatly enhanced if a high concentration of nitrogen is also injected, and that the gas swap is a two-step process. (Nitrogen is readily available anywhere, because it makes up 78 percent of the earth’s atmosphere.)