As the unique source of carbon in the atmosphere and exhaust air, carbon dioxide (CO2) exerts a strong impact on crop yield and quality. However, CO2 deficiency in greenhouses during the daytime often limits crop productivity. By capturing CO2 from the gas engines during the nighttime, storing the CO2 at site and dosing the CO2 controlled into the greenhouse, a greenhouse can save energy without affecting plant activity and is in full CO2 dosing control.