Evaluation of sustainability aspect – energy balance of briquettes made of hemp biomass cultivated in Moldova
¹Faculty of Tropical AgriSciences, Czech University of Life Sciences, Kamycka 129, 12641Praha 6, Czech Republic; 2Central Bohemia University, Pod Vodarenskou vezi 4, 18200Praha 8, Czech Republic *Correspondence: email@example.com
Biomass is currently a significant source of energy mainly for its availability and high potential. Energy crops suitable for energy purposes must have a positive energy balance within the whole production cycle. Industrial hemp (Cannabis sativa L.) has a high yield in a short period of time and reaches a gross calorific value similar to that of wood. Two hemp cultivars were experimentally sown in the Republic of Moldova in order to determine the yield and energy balance for utilization of solid fuels in the form of briquettes. Briquettes were considered to be used in small – scale boilers for heating purposes with a thermal efficiency of 80%. Hemp harvested as a green plant in autumn was left under a roof for losing moisture, to keep yield as high as possible and left the field for another crop in rotation system. The energy balance included all forms of inputs – energy of human labor, energy in fuels, in seeds and in the machines during the technological process according to common practises in Moldova. Energy Return on Energy Invested (EROEI), due to the large share of manual labor and agricultural practices without using of fertilizers, exceeded the value of 12.6. This means that it is classified as very suitable for energy purposes. Hemp appears to be a promising energy crop in temperate climate and it is able to contribute solving the energy situation in Moldova.