Life cycle assessment of bio-methane supply system based on natural gas infrastructure

M. Repele*, A.Paturska, K. Valters and G. Bazbauers

Institute of Energy Systems and Environment, Riga Technical University, Kronvalda Boulevard 1, Riga, LV1010, Latvia; *Correspondence: mara.repele@rtu.lv

Abstract:

Many sites for biogas production in Latvia currently do not have sufficient heat load to provide power production in co-generation mode. The alternative to relatively inefficient power production could be production of bio-methane which is known as one of the most important renewable option for gas supplies. After removal of contaminants bio-methane is of quality of natural gas and can be delivered to power plants and industry using the natural gas supply infrastructure. For analysis of environmental benefit of using bio-methane the environmental impact of the proposed solution has to be assessed. The aim of the study is to make life cycle assessment of the system for bio-methane supply to industrial plant via the natural gas grid. The analysed system includes bio-methane production and transport to the natural gas pipeline including the infrastructure. Functional unit was 1 MWh of bio-methane energy injected into the natural gas transmission pipeline. Life-cycle model was created and analysed with software ‘SimaPro’. ReCiPe and Eco-Indicator’99 were used as characterization methods to analyse the life-cycle environmental impacts. Results show the influence and contribution level expressed in mid-point categories as well as in a single-score indicator. The largest impact is created by use of fossil energy sources in production of bio-methane. The results can be used to design renewable energy supply systems and for the comparison of alternatives.

Key words:

bio-methane, life cycle assessment, natural gas, renewable energy

Environmental aspects of substituting bio-synthetic natural gas for natural gas in the brick industry

M. Repele*, M. Dudko, J. Rusanova, K. Valters and G. Bazbauers

Institute of Energy Systems and Environment, Riga Technical University,Kronvalda Boulevard ¹, Riga, LV¹0¹0, Latvia;*Correspondence: mara.repele@rtu.lv

Abstract:

Firing of bricks is an essential manufacturing process during which the bricks obtainall the necessary properties. Life cycle assessment studies show that this process is also themost energy intensive in the brick manufacturing process and results in the largestenvironmental impact. Usually kilns are fired with natural gas, therefore substitution of fossilfuel with a renewable energy source is considered one of the most effective approaches forreduction of environmental impact. Bio-synthetic natural gas (bio-SNG) is one of the mostfeasible substitutes for natural gas and therefore the aim of the study was to compare theenvironmental impacts of those energy sources.Comparison of the life cycle of the environmental impact of natural gas and bio-SNG wascarried out using the GEMIS (Global Emission Model for Integrated Systems) database. Bothenergy sources were compared on the basis of the life cycle of CO² emissions, cumulatedenergy and material requirement, land use and employment effects.Results show that by replacing natural gas with bio-SNG, greenhouse gases could be reducedand employment increased. However, cumulated energy, material and land requirement is largerwhen bio-SNG is used instead of natural gas.

Key words: