Applying negative emissions technologies in the superfoods sector: How far are we from achieving a carbon neutral spirulina production?

Environmental degradation is one of the biggest challenges of our time, with a negative influence on society by stressing food and forestry systems. However, these negative effects are reciprocal, as around 50% of food is produced under conditions transgressing some planetary boundaries. As a consequence, new opportunities for food supply chain stakeholders are occurring around the world; among them, the development of alternative nutrient sources and the implementation of carbon removal technologies are highlighted as mitigation pathways compliant with carbon neutrality targets.

This study seeks to prove the effectiveness, through carbon accounting and carbon footprint (CF), of two carbon capture and utilization techniques in the production of spirulina, an increasingly known and consumed ‘superfood’. Spirulina is considered an important CO₂ consumer and in its industrial production this supply is made by means of synthetic CO₂. Two scenarios that aim to reduce the associated burdens are compared: (i) use of CO₂ recovered from the fermentation of beer (SP_BRW), and (ii) use of CO₂ from a direct air carbon capture unit (SP_DACC).

The results show that both scenarios present better environmental performance than current production methods. The CFs are estimated at 1.03 tons and 1.37 tons CO₂ eq./year for the SP_BRW and SP_DACC scenarios, respectively. In accordance, carbon accounting confirms that only CO₂ emissions can be reduced, compared with the business-as-usual scenario, by up to 51.1% by using residual emissions from breweries and 47% by capturing CO₂ from air. These findings provide a starting point in developing robust and transparent carbon accounting that verifies the efficiency of carbon removal in food systems, particularly in the superfoods sector. Future challenges focus on technical feasibility, in terms of the technology readiness level and implementation, as well as economic feasibility, since their actual application, especially of the DACC, would require a significant investment.