Feasibility of microalgae farms as an alternative technology for carbon sequestration under the temperate climate conditions of Central Russia

Abstract

Microalgae farms offer a promising route for carbon capture owing to the high photosynthetic efficiency of microalgae (10–20%) versus terrestrial plants (1–2%) and to their ability to use industrial CO₂ and wastewater nutrients. This study calculates the carbon balance of a hypothetical 100 m² photobioreactor farm in the temperate climate of Central Russia (Kazan), supplied with thermal-power-plant flue gas and treated municipal wastewater. At a productivity of 3.5 g/L per day, photosynthetic CO₂ uptake (642.25 kg/day) exceeds combined emissions (21.7 kg CO₂/day), giving a negative footprint of approximately −226.5 t CO₂/year and supporting farm feasibility for carbon sequestration in a temperate climate. Achieving this productivity, however, requires strains tolerant to flue gas/wastewater contaminants and pH/temperature fluctuations, making closed photobioreactors a realistic but demanding route to carbon-negative biomass production in temperate regions.