Assessment of Areal Methane Yields from Energy Crops in Ukraine, Best Practices

Abstract

Growing and utilizing bioenergy crops as feeding substrates in biogas plants may aid the development of the biogas sector in Ukraine. Therefore, research was done on potential methane yields from 22 high-yield varieties of 7 different crops grown in Ukraine for their biogas production suitability. Annual crops (maize, soybean, sweet sorghum and sorghum hybrids) and perennials (miscanthus, paulownia and switchgrass) harvested at three different harvesting times (H1, H2 and H3) related to specific stages of phenological development were investigated. The perennial crops studied were from different vegetation years. The samples were analysed in Ukraine on their dry matter- and volatile solids contents, dry matter yield (DMY) and crop nitrogen (N) uptake. The 55 °C -dried samples were delivered to Germany for their analysis with the Hohenheim Biogas Yield Test (HBT) on their specific methane yield (SMY). Based on DMY and SMY, the areal methane yields (AMY) were calculated. The highest SMY and AMY were found for maize, sweet sorghum and miscanthus. The highest average SMY of 0.35 ± 0.03 m3CH4 kgVS−1 was found for maize samples harvested at H2. Miscanthus “Giganteus” from the 8th vegetation year harvested at H1 has shown the highest AMY of 7404.50 ± 199.00 m3CH4 ha−1.

Keywords

• anaerobic digestion
• biogas
• maize
• soybean
• sorghum
• miscanthus