Carbon balance of biogas production from maize in Latvian conditions

K. Bumbiere, A. Gancone, J. Pubule* and D. Blumberga

Riga Technical University, Institute of Energy Systems and Environment, Faculty of Electrical and Environmental Engineering, Azenes 12-K1, LV-1048 Riga, Latvia
*Correspondence: jelena.pubule@rtu.lv

Abstract:

Production of biogas using bioresources of agricultural origin plays an important role in Europe’s energy transition to sustainability. However, many substrates have been denounced in the last years as a result of differences of opinion on its impact on the environment, while finding new resources for renewable energy is a global issue. The aim of the study is to use a carbon balance method to evaluate the real impact on the atmosphere by carrying out a carbon balance to objectively quantify naturally or anthropogenically added or removed carbon dioxide from the atmosphere. This study uses Latvian data to determine the environmental impact of biogas production depending on the choice of substrate, in this case from specially grown maize silage. GHG emissions from specially grown maize use and cultivation (including the use of diesel fuel, crop residue and nitrogen fertilizer incorporation, photosynthesis), biogas production leaks, as well as digestate emissions (including digestate emissions and also saved nitrogen emissions by the use of digestate) are taken into account when compiling the carbon balance of maize. The results showed that biogas production from specially grown maize can save 1.86 kgCO₂eq emissions per 1 m³ of produced biogas.

Key words:

agriculture., bioenergy, biofuels, multicriteria analysis, sustainability

Conceptual ‘Cradle to Gate’ analysis of GHG emissions from wood, agricultural plant and synthetic fibres

V. Kazulis*, I. Muižniece and D. Blumberga

Riga Technical University, Faculty of Power and Electrical Engineering, Institute of
Energy Systems and Environment, Azenes iela 12/1, LV-1048 Riga, Latvia
*Correspondence: valters.kazulis@rtu.lv

Abstract:

Industrialization and fossil resource use has brought unprecedented anthropogenic carbon dioxide emissions. Use of synthetic fibre materials and unsustainable plant cultivation practices contribute to greenhouse gas emissions. The global market share of polyester fibre (synthetic fibre made from fossil resources) exceeded the share of cotton fibre (natural fibre) for the first time in 2000 and since then polyester has remained the most popular fibre. The demand for textiles keeps increasing. In Northern Europe locally made fibres from wood, hemp and flax could substitute fossil based fibres decreasing the global GHG emissions and helping local economies to prosper. Multi-criteria analysis method TOPSIS was used to carry out a conceptual research evaluating GHG emissions from wood, agricultural plant and synthetic fibre acquisition under two scenarios: fossil fuels are used as energy sources & industrial fertilizers are used; and renewable energy sources are used & industrial fertilizers are not used. Results show that wood and plant fibres have smaller GHG emissions than synthetic fibres in both scenarios. Factors affecting emission performance are analysed.

Key words: