Abstract Novel approaches to practice CO 2 enrichment in greenhouses from the exhaust gas of a biomass heating system are reviewed. General CO 2 enrichment benefits for greenhouse plant production are described along with optimal management strategies to reduce fuel consumption while improving benefits. Alternative and renewable fuels for CO 2 enrichment, landfill biogas and biomass, are compared with traditional methods and fuels. Exhaust gas composition is outlined to address the challenges of CO 2 enrichment from biomass combustion and leads to a comparison between combustion and gasification to improve boiler efficiency. In terms of internal modifications to a biomass heating system, syngas combustion, following biomass gasification, presents good potential to achieve CO 2 enrichment. Regarding external modifications to clean the exhaust gas, CO 2 can be extracted from flue gases via membrane separation that has shown a lot of potential for large industries trying to reduce and isolate CO 2 emissions for sequestration. Other research has optimized wet scrubbing systems by extracting SO 2 and NO emissions from flue gases to form ammonium sulphate as a by-product valuable to fertilizer markets. The potential of these techniques are reviewed while future research directions are suggested.