Extracting carbon emissions from the atmosphere is evolving into a substantial industry—businesses are investing significant amounts in technologies that can offset their emissions.
Currently, approximately 70% of announced carbon removal agreements are for a single technology: bioenergy with carbon capture and storage (BECCS). Essentially, the concept involves utilizing trees or certain types of biomass for energy and capturing the emissions released during combustion.
Although corporations, including technology leaders like Microsoft, are heavily investing in this technology, there are several potential issues with BECCS, as detailed by my colleague James Temple in a recent article. Some concerns mirror similar challenges with other climate solutions we examine, including carbon offsets and alternative aviation fuels.
Carbon calculations can be intricate.
To illustrate one of the significant challenges with BECCS, we need to explore the logic behind its carbon accounting. (And although this technology can utilize a variety of biomass forms, let’s focus on trees.)
As trees grow, they absorb carbon dioxide from the atmosphere. Those trees can be harvested for various purposes, such as producing paper. The residual material, which might otherwise be considered waste, is then processed and combusted for energy.
This process is, in theory, carbon neutral. The emissions generated from burning the biomass are balanced by what was absorbed from the atmosphere during the plants’ growth. (Assuming those trees are replanted after harvesting.)
Now envision that carbon-scrubbing technology is installed at the facility that burns the biomass, capturing emissions. If the cycle was logically carbon neutral previously, it’s now carbon negative: Net emissions are extracted from the atmosphere. Sounds promising, no issues noted.
However, there are a few flaws in this math. For one, it neglects the emissions that could be generated during the harvesting, transportation, and processing of the wood. Additionally, if projects necessitate land clearing to plant trees or cultivate crops, that transition can also result in emissions being released.
Challenges with carbon calculations may seem somewhat familiar if you’ve read any of James’s coverage on carbon offsets, programs where individuals pay for others to reduce emissions. Particularly, his 2021 investigation with ProPublica’s Lisa Song outlined how this supposed solution was actually contributing millions of tons of carbon dioxide to the atmosphere.
Carbon capture might reinforce polluting facilities.
A significant advantage of BECCS is that it can be integrated into existing facilities. There’s less construction involved compared to something like a facility that directly extracts carbon from the air. This helps reduce costs, making BECCS currently much more affordable than direct air capture and other carbon removal methods.
However, maintaining outdated equipment might not be beneficial for emissions or local communities in the long term.
Carbon dioxide is hardly the only pollutant emitted by these facilities. Burning biomass or biofuels can release compounds that negatively impact human health, such as particulate matter, sulfur dioxide, and carbon monoxide. Carbon capture systems may trap some of these pollutants, like sulfur dioxide, but not all.
The assumption that waste material wouldn’t have been used otherwise may be incorrect.
It seems advantageous to utilize waste, but there’s a major caveat, as James explains in the article:
However, the crucial inquiry that arises with waste is: Would it otherwise have been incinerated or left to decompose, or might some portions have been repurposed in a manner that prevented carbon from entering the atmosphere?
Biomass can be repurposed for various applications, such as creating plastic, construction materials, or even soil amendments that enhance crop nutrient absorption. Thus, the presumption that it’s BECCS or nothing is flawed.
Furthermore, a peculiar phenomenon occurs when waste is given value: There’s a motivation to generate more of it. Some experts worry that companies could end up cutting down more trees or clearing more forests than what is necessary to produce additional materials for BECCS.
These waste concerns remind me of discussions about sustainable aviation fuels. These alternative fuels can be derived from a wide array of materials, including agricultural waste or even used cooking oil. However, as the demand for these eco-friendly fuels has surged, some anomalies have emerged—there are even reports of fraud, where dishonest individuals attempt to sell newly produced oil from crops as used cooking oil.
BECCS represents a potentially valuable technology, but similar to many aspects of climate technology, it can rapidly become complex.
James has been covering carbon offsets and carbon removal for years. As he remarked to me this week during our discussion about this article: “Simply reduce emissions and stop complicating things.”
This article is from The Spark, MIT Technology Review’s weekly climate newsletter. To receive it in your inbox every Wednesday, sign up here.
