Techno-economic study of a small scale gasifier applied to an indoor hemp farm: From energy savings to biochar effects on productivity

The hemp market is fast growing due to demand for cannabidiol, nutraceutical and hemp fiber products. This work demonstrates the economical advantage of biomass gasification application to indoor hemp production. Gasifiers provide electrical energy, heat and biochar: these are highly valuable products for indoor growers where lights and thermal management are key costs of the business. Energy produced in an autonomous and renewable way increases the sustainability and in the facility. In this paper a small scale gasifier is fueled with certified “A1 plus” wood pellets to test its behavior and its biochar production rate. Biochar is used for hemp growing tests in an indoor hemp production facility. Results show how a 22 kW power plant is sufficient to guarantee almost complete sustainability in a 80 m2 facility. In the best case scenario where energy saving, biochar and thermal energy selling are considered, the gasifier investment has a payback time of about 3.5 years. At the end of the gasifier lifespan, the Net Present Value reaches 249 k€ considering a discount rate of 6%. Consequential results were also obtained from biochar application to pot growing substrates: there was a 7.7% increase in dry flower production and a 33.9% increase in total plant fresh biomass. Cannabinoids profiles resulted not affected by biochar application.