What is carbon capture and storage?

Capture

The idea of capturing CO₂ emissions before they hit the atmosphere may seem like a futuristic solution, but the technology exists and continues to mature.

ExxonMobil is a global leader in carbon capture and storage. It was the first company to capture more than 120 million metric tons of CO₂ through CCS, which is equivalent to removing the annual emissions of more than 25 million cars.

The company’s scientists and engineers are working with outside collaborators to scale CCS to help capture CO₂ from the natural gas used to power heavy industrial sites. Only 4% of the exhaust from natural gas turbines is made up of CO₂, meaning it’s incredibly difficult to capture.

CCS is vital because it’s one of the few proven technologies that that can help decarbonize energy-intensive industries and lower emissions to levels required to meet the world’s climate targets in the Paris Agreement. While renewables will also play a role, they are considered intermittent energy sources and may not be able to always keep up with the high energy demand required to manufacture products like concrete or steel.

ExxonMobil is also conducting early-stage research on two additional CCS technologies. One is using a fuel cell to capture emissions before they are released from a natural gas-fired power plant or an industrial facility. The other, known as direct air capture, aims to capture CO₂ emissions directly from the atmosphere.

At scale, CCS could help reduce emissions from hard-to-decarbonize industries like manufacturing and power generation. Combined, these two sectors account for approximately two-thirds of the world’s energy-related emissions.

Once captured, the next step is to transport the CO₂ underground, and store it safely, securely and permanently.

Storage

Storing CO₂ is a complex undertaking that requires some of the same expertise ExxonMobil deploys to produce and supply the world with energy – in particular, the understanding of geologic formations. In the case of CCS, the company’s geologists identify underground sites in which to store the captured CO₂ molecules.

CO₂ can be safely stored in underground natural, porous rock formations. The United States Department of Energy estimates there is at least 2.4 trillion metric tons of CO₂ storage capacity in saline formations and depleted oil and gas reservoirs across the country. That underground capacity is large enough to permanently put away hundreds of years’ worth of CO₂.

In the Gulf of Mexico alone, a prolific oil and gas producing region, reservoirs underneath the seabed could hold an estimated 500 billion metric tons of CO₂ – the equivalent of 130 years’ worth of U.S. industrial and power generation emissions.

One way to streamline the capture, transportation and storage of industrial CO₂ emissions is through multiuser CCS hubs in places like Houston. This type of collaborative effort would capture emissions from ExxonMobil and other participating companies operating in the area. By 2040, the hub could store about 100 million metric tons of CO₂ annually in secure geological formations.

The hub could act as a blueprint for other industrial areas across the U.S. and around the world.

Capturing and then safely storing the world’s industrial CO₂ emissions is an ambitious endeavor, but it’s critical in helping to address the impact of climate change. ExxonMobil will continue doing its part to advance CCS and other emission-reduction technologies that could put the world on the right path toward a lower-emissions energy future.