Dear Earthtalk: Are CO2 capture technologies a dream of the future or really feasible as a technique to mitigate global warming?
The short answer is…we’ll see. To understand how carbon dioxide (CO2) gets removed from our atmosphere, it’s important to first look at how it gets there and why it’s a problem in the first place.
Human activities contribute significantly to CO2 emissions through the burning of fossil fuels, electricity consumption and transport. According to NASA, since the 18th century, humans have caused CO2 concentrations to increase by half, resulting in a temperature rise of 1.8°F. This may seem insignificant, but the consequences are becoming increasingly apparent, leading scientists to scramble to find ways to limit potentially irreversible impacts in the future. Various emission reduction strategies are being put into play to help stave off the worst effects of global warming.
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One of the most promising is the so-called “Carbon Capture and Storage” (CCS). Technologies that prevent carbon from entering the atmosphere by storing it have been around since the mid-1970s, but only recently have they been scaled to meet the needs of larger industrial settings. CCS consists of three steps: collection, transport and storage. First, CO2 is separated from other gases that are released during industrial processes. Next, the CO2 is sent through pipelines where it is then stored and often reused. Currently 80 institutions are in the process of implementing CCS, 16 have already done so. Its removal efficiency is targeted at 90%, with some reaching 95-99%.
CCS is certainly a viable method to remove CO2 from the atmosphere. Most CO2 emissions come directly from a facility; The greatest benefit of CCS is its ability to prevent CO2 escaping at source. The International Energy Agency estimates that CCS is capable of removing up to 20% CO2 from industrial plants. Other greenhouse gases such as nitric oxide and sulfur dioxide can also be sequestered. The captured CO2 can also be used to manufacture other commercial products such as concrete and polymers. Geologically stored CO2 can be reused to extract geothermal energy, making geothermal energy sustainable.
While this sounds like a perfect solution to our problems, there are some potential pitfalls. Although CCS has high efficiency, the 90% of CO2 emissions is not enough considering where we are with emissions at the moment. With the race to develop maximum distance CCS projects, costs are also escalating sharply. According to the Global CCS Institute, the 26 plants built by 2021 have removed just 0.1% of emissions, meaning that to be viable, this technology would have to be applied to every industrial plant in the world – now. So we have a situation where the costs outweigh the benefits, and given the unpromising results, “…there’s no way to get better than directly replacing coal or gas with wind or solar,” says Mark Jacobson of Stanford. “The latter will always be better in terms of social costs no matter what.”
Most environmentalists agree that focusing on renewable energy is the best course of action to reduce our greenhouse gas emissions. Nonetheless, CCS remains a viable weapon in the arsenal of climate change campaigners. With the advancement of various technologies, it will play an especially important role as a bridge to a sustainable future for the planet.