From biogas to hydrogen: A techno-economic study on the production of turquoise hydrogen and solid carbons

Abstract

Biogas is a renewable feedstock that can be used to produce hydrogen through the decomposition of biomethane. However, the economics of the process are not well studied and understood, especially in cases where solid carbons are also produced, and which have a detrimental effect on the performance of the catalysts. The scale, as well as product diversification of a biogas plant to produce hydrogen and other value-added carbons, plays a crucial role in determining the feasibility of biogas-to-hydrogen projects. Through a techno-economic study using the discounted cash flow method, it has been shown that there are no feasible sizes of plants that can produce hydrogen at the target price of USD 3/kg or lower. However, for self-funded anaerobic digestor plants, retrofitting modular units for hydrogen production would only make financial sense at biogas production capacities of more than 412 m3/h. A sensitivity analysis has also shown that the cost competitiveness is dependent on the type of carbon formed, and low-grade carbon black has a negative effect on economic feasibility. Hydrogen produced from biogas would thus not be able to compete with grey hydrogen production but rather with current green hydrogen production costs.