Energy harvesting from algae using large-scale flat-tube solid oxide fuel cells

Algae have emerged as a promising sustainable energy source; however, efficient methods for generating electricity from algae are still lacking. In this study, power generation using large-scale flat-tube solid oxide fuel cells fueled with biosyngas from microwave-enhanced pyrolysis of algae is demonstrated. The power density of a cell fueled with biosyngas from laminaria is 379.8 mW/cm² under 0.8 V at 750°C, which is approximately 91.7% of the density of a cell fueled with pure hydrogen. Fueled with dry syngas (laminaria), the cell fails within 3 h because of carbon deposition. Adding 5 vol % H₂O to syngas (laminaria) inhibits carbon deposition and enables 800 h of galvanostatic operation without degradation under 200 mA/cm² at 750°C. A 100-cycle pulsed operation of the cell with syngas (laminaria, 5 vol % H₂O) under different loads, simulating practical scenarios with variable energy demands, is obtained. Based on the simulation results, the temperature fluctuations within the cell under different current densities are analyzed. Overall, this work advances practical efforts to improve solid oxide fuel cells for biosyngas consumption.