Biomass Sustainability: Critical for Carbon Removal

Today, prominent climate models project that biomass energy with carbon capture and storage ("bio-CCS") projects will play a significant role in the fight against climate change:

Above: The blue line in the chart above, from the paper "BECCS capability of dedicated bioenergy crops under a future land-use scenario targeting net negative carbon emissions" by Etsushi Kato and Yoshiki Yamagata, shows that billions of tonnes of biomass will be needed to generate the net-negative carbon emissions required to prevent climate change. 

Deploying such large quantities of bio-CCS, however, will not be without its challenges, as highlighted by a recent report from the World Resources Institute (WRI). For example, the report finds that "dedicating crops and/or land to generating bioenergy makes it harder to sustainably feed the planet."

WRI Figure 3
WRI Figure 3

Above: Figure from the WRI report "Avoiding Bioenergy Competition for Food Crops and Land"

The report, however, goes on to conclude that "phasing out bioenergy that uses crops or that otherwise makes dedicated use of land is a sound step toward a sustainable food future." A sustainable food future, perhaps. But a sustainable climate future? This recommendation to phase out dedicated bio-energy crops would severely curtail biomass energy fuel supplies, in the process making billion+ ton deployments of bio-CCS very challenging.

What's more, the suggestion from the WRI report of deploying solar PV instead of bioenergy is likely to increase the cost of negative-emission goals considerably. Solar PV could be used with direct air capture ("DAC") systems with CCS to remove carbon from the atmosphere, but today this type of carbon dioxide removal ("CDR") system would likely cost significantly more than biomass-based CDR projects.

The potential for bio-CCS to provide large-scale, cost-effective CDR is an often overlooked aspect of the bioenergy conversation. But the WRI report does specifically provide three such reasons why even pursuing bio-CCS for CDR is not worthwhile. The rationale given for each argument, however, falls flat:

WRI Report Argument Against Bio-CCS #1: "Carbon capture does not transform non-additional biomass that cannot generate carbon savings into additional biomass that can." Bio-CCS can utilize "additional" biomass -- cellulosic ethanol projects that utilize crop wastes, for example, have been slow to develop, but that doesn't mean such projects cannot scale up with the right policy and market support. It will be important to ensure sustainability and "additionality" of biomass supplies for energy, and while this is likely to prove challenging, it is far from impossible. Argument grade: C

WRI Report Argument Against Bio-CCS #2: "There is no benefit to applying carbon capture and storage even to additional biomass until all fossil fuel emissions have been eliminated or captured and stored." There might not be benefits to atmospheric carbon concentrations, but there are almost certainly benefits for learning how to optimize bioenergy systems, build out biomass supply chains, and smooth the transition to a carbon-removing economy. If our economy eventually has to generate net-negative levels of carbon emissions, it will prove politically and economically beneficial to de-risk bio-CCS technology as much as possible today so that once we do stop using coal and natural gas, we are able to generate energy from biomass as economically as possible. Argument grade: D.

WRI Report Argument Against Bio-CCS #3: "even if there were a special benefit from BECCS, this is not a reason to use biomass today without carbon capture and storage." The same logic applies as above: it is important to de-risk biomass generation systems and build biomass supply chains today. Biomass projects without CCS technology could pave the way for most cost-effective bio-CCS project in the future. Argument grade: D.

So where does this leave us? The most important conclusion is that we are likely going to need both increased crop production and increased bioenergy consumption to prevent climate change while feeding a growing population. As a result, it is critical that we expand the conversation on developing systems that achieve both goals. We need to understand the conditions under which bioenergy can be scaled "additionally" and sustainably, so we can focus on building the most sustainable and cost-effective portfolio of CDR systems to prevent climate change while meeting the other basic social and environmental needs of a growing global population.