Negative emissions technologies (NETs) are methods for removing CO2 from the atmosphere using either natural or man-made processes. NETs have come into the spotlight in recent years due to their beneficial impact on IPCC models. For example, models that include rapid development of NETs forecast net negative emissions by the end of the century.
The prospect of negative emissions is exciting because it represents a strategy for effectively reversing the principal driving force of climate change, atmospheric CO2 . Besides being a handy trick for climate modelers trying to keep their model outputs below 2°C, these technologies represent a creative, potentially viable solution to the complex problem that is climate change. NETs exist in a variety of forms. In the broadest sense, reforestation is a NET as it results in the removal of CO2 from the atmosphere. While reforestation is clearly an essential component of any climate change mitigation portfolio, some of the more ambitious NETs that people are currently working on are much more exciting.
Bioenergy with carbon capture and sequestration (BECCS) is a strategy to produce negative CO2 emissions by farming fast-growing grasses and trees that can soak up large amounts of carbon, burning them for energy, capturing the CO2 produced, and pumping it underground. This strategy is unique because it effectively creates a renewable carbon sink. By farming fast growing crops like poplar trees and switchgrass, we can remove CO2 from the atmosphere while simultaneously producing a renewable source of energy. These crops can then be burned at biomass plants equipped with carbon capture and sequestration (CCS) technology, which compress and liquefy the CO2 before pumping it deep underground, back to where it originally came from.
The main goal of this project is to achieve net negative CO2 emissions by the end of the century. If this technology were successfully implemented, it would theoretically give us more time to reign in our emissions as a significant chunk of them could be offset by “negative emissions”. If proven effective, this technology could have a direct impact on the level of global warming that we see in the coming decades—which would be a huge victory for the planet.
Obviously this idea is very ambitious and has yet to be proven on a grand scale but I believe that solving a problem as large and complicated as climate change requires new ways of thinking. BECCS specifically, and NETs in general are creative solutions to a complex global problem. The technology behind BECCS is also not as far-fetched as it may seem. Both bioenergy and carbon capture and sequestration are currently operating around the world, at least to some extent. Plenty of power plants are currently burning biomass, including the McNeil Plant right here in Burlington, and a Norwegian oil company has been sequestering CO2 underground for over 20 years. Although these two technologies have yet to be paired on any meaningful scale, there is no reason to believe that they won’t in the future—especially as the cost of CCS drops. Reducing our CO2 emissions is still the best thing we can do in the meantime, but if NETs rise to prominence, we may soon be able to reverse them.