Limits on the global potential for BECCS are mainly due to the need for sustainable water management practices

In a recent study published in the prestigious journal Nature Sustainability, researchers aimed to determine the extent to which irrigation could enhance the global potential of Bioenergy with Carbon Capture and Storage (BECCS) under sustainable water use.

BECCS is a process that extracts bioenergy from biomass, captures, and stores carbon in geological reservoirs. It is considered a negative emission technology that uses plants to absorb carbon dioxide from the atmosphere. The study's findings suggest that irrigation can significantly increase the global BECCS potential under sustainable water use.

The study found that under sustainable irrigation, the BECCS potential was 0.88-2.09 Gt C yr-1, representing a 5% and 6% increase compared to that under rainfed conditions. Moreover, under full irrigation, the BECCS potential was 1.32-3.42 Gt C yr-1, showing a 60% and 71% increase compared to the rainfed condition.

These increases are crucial, as large-scale deployment of BECCS is assumed to be prominent in many previous studies to achieve the 2°C or 1.5°C climate goal. However, concerns about the challenges brought to water and land resources due to growing bioenergy crops for BECCS are valid.

The global potentials of BECCS are increased through sustainable irrigation primarily by improving water management that maintains local and downstream water availability for conventional uses and environmental flows, avoids the depletion of non-renewable water sources, and prevents additional water stress. Regions where sustainable irrigation can enhance these potentials are generally those where water use efficiency is optimized without compromising ecosystem services or water security.

However, irrigating bioenergy crops for BECCS potential could lead to severe water stress, even more than climate change itself. Therefore, comprehensive assessments of BECCS potential that consider both potential benefits and adverse effects are necessary.

The study's findings could have implications for future strategies in the large-scale deployment of BECCS while minimizing negative environmental impacts. The research was supported by the Environment Research and Technology Development Fund of the Environmental Restoration and Conservation Agency of Japan (JPMEERF20202005, JPMEERF15S11418, and JPMEERF20211001). The DOI for the study is 10.1038/s41893-021-00740-4.