Knowledge Base

CO₂ liquefaction is the process of converting gaseous CO₂ into a liquid state, known as liquid CO₂ or LCO₂, so it can be stored, transported, and sold as a commercial product rather than released or vented. In a biogas plant, this CO₂ originates as a byproduct of biogas upgrading, where it is separated from methane to produce biomethane. Because this CO₂ comes from the anaerobic digestion of organic material, it is classified as biogenic CO₂. When produced to the right purity, it can be certified as food-grade, making it suitable for use in the food and beverage industry. HoSt’s Lorca Bioenergy project in Spain illustrates the scale this can reach, alongside 29 million Nm3 of biomethane per year, its CO₂ liquefaction systems, supplied by Bright Renewables, are designed to produce over 40,000 tons of food-grade liquid bio-CO₂ annually.