Global potential of sustainable single-cell protein based on variable renewable electricity

The environmental impacts of the food system exceed several planetary boundaries, with protein production being a major contributor. Single-Cell Protein (SCP) is a protein-rich microbial biomass that offers a sustainable alternative when derived from renewable energy and sustainable feedstocks. We evaluate the global potential for SCP production utilising electrolytic hydrogen and oxygen, atmospheric carbon dioxide and nitrogen, and hourly-optimised hybrid PV-wind power plants at a 0.45° × 0.45° spatial resolution. We outline a roadmap for industrial-scale production, commencing in 2028, targeting an annual capacity of 30 million tonnes of protein by 2050. Here we show that the cost of renewable electricity-based protein (e-protein) could decline at optimal sites from 5.5-6.1 € kg^-1 in 2028 to 4.0-4.5 € kg^-1 by 2030, and further to 2.1-2.3 € kg^-1 by 2050. Consequently, e-protein production can mostly decouple protein supply from water and arable land constraints, substantially mitigating the environmental impacts of food production.