The present study analyses the environmental impact of electricity production from two different sources: natural gas and biogas upgraded, the so called bio-methane. Through LCA approach, several indicators are evaluated according to ReCiPe model in GaBi software. The analysis is applied to two different case studies, Germany and Italy, and the perspective is a substitution approach: bio-methane is seen as a valuable bio-fuel compared to natural gas. Our analysis aims to evaluate the impact of the production of 1 kWhel produced by the two technologies. The reasons comes from the Germany contest: its national energy plan, to be complied by 2020, includes decommissioning of nuclear power plants to be substitute by renewables and substitution of natural gas as fuel with bio-methane . LCA methodology was chosen because the study wants to give an overview of all environmental indicators affected by the two technologies, considering emission to water, soil and air. The results show how biogas production significantly affects indicators such as Climate Change, Terrestrial Acidification, Eutrophication, Particulate Matter Formation and Ozone Depletion. Reasons can be found in agricultural practices, emission to air and soil caused by energy crops and their fermentation. Crop yield and transport can vary prominently, thus it affects emissions to air, soil and water in a very variable way. Sensitivity analysis helped to evaluate our assumption and confirmed our results. EU directives for renewable power production and emission reduction are duly taken into consideration. Germany and Italy use different policy to support the improvement of renewable sources, in particular biogas and bio-methane. This last one is currently not supported by Italian Renewable Act. That’s why no bio-methane plant has been installed yet. An overview of the current policies in Germany and Italy is given and an economic analysis is performed. The production cost of bio-methane compared to natural gas in both countries showed lower costs in Germany. We also verified the profitability of a bio-methane plant in Germany. The comparative analysis for biogas power plant in Germany and Italy showed higher profitability in Germany, thanks to the supporting policy. For both bio-methane and biogas the most influencing cost items are the agricultural cost. The result was confirmed by the sensitivity analysis. Conclusions highlight the environmental damages of biogas for massive electricity production, caused by today’s energy crops practices and the high costs to support them. Agricultural practices should be improved and cost reduced to make the investment environmentally sustainable and economically profitable.
Il presente progetto si occupa di analizzare l’impatto ambientale provocato dalla produzione di energia elettrica da due fonti differenti: gas naturale e biogas purificato, il cosiddetto bio-metano. Attraverso questo studio LCA, sono stati valutati diversi indicatori appartenenti al cosiddetto modello ReCiPe contenuto nel software GaBi. L’analisi è applicata a due casi studio, Germania e Italia, e lo studio è stato realizzato secondo un approccio sostitutivo: il bio-metano ad oggi è visto come un valido bio-carburante, se paragonato al gas naturale. La nostra analisi si dà l’obiettivo di valutare l’impatto che hanno queste due tecnologie nel produrre 1 kWh elettrico. Le ragioni di questo studio vengono offerte dal contesto tedesco: il piano nazionale energetico germanico, da essere portato a termine entro il 2020, prevede la chiusura e lo smaltimento delle centrali nucleari presenti nel paese, al fine di sostituire l’energia elettrica da esse prodotto con fonti rinnovabili. In particolare il piano prevede inoltre la sostituzione del gas naturale con il bio-metano. È stata scelta la metodologia LCA perché lo studio vuole dare una visione completa dell’impatto ambientale delle due tecnologie a confronto, considerando emissioni nell’acqua, suolo e aria. I risultati mostrano come la produzione di energia elettrica da biogas influenza significativamente indicatori come Climate Change, Terrestrial Acidification, Eutrophication, Particulate Matter Formation e Ozone Depletion. Le ragioni si trovano principalmente nelle pratiche agricole e nelle emissioni in aria, suolo e acqua causate dalle coltivazioni energetiche e la loro fermentazione. Il rendimento del raccolto e la distanza del suo trasporto possono variare notevolmente, influenzando le emissioni. L’analisi di sensibilità svolta aiuterà a valutare le nostre assunzioni e confermare i risultati. Le direttive dell’Unione Europea, riguardo la produzione di energia elettrica da rinnovabili e la riduzione di emissioni, sono strettamente tenute in considerazione. Germania e Italia utilizzano diverse politiche al fine di supportare lo sviluppo di un parco rinnovabili, in particolare ci concentriamo su biogas e bio-metano. Quest’ultimo è attualmente non supportato finanziariamente dal Decreto Rinnovabili in Italia. Per questo, al contrario della Germania, in Italia non esistono impianti di produzione di bio-metano. Viene data una visione globale delle politiche di supporto tedesca e italiana e viene svolta una analisi economica. Il costo di produzione del bio-metano confrontato con quello del gas naturale mostra come i costi si mantengano più bassi in Germania. È stato inoltre verificata la profittabilità di tale investimento in Germania. L’analisi prosegue con il confronto di impianti di produzione di energia elettrica alimentati a biogas, che mostrano maggiore profittabilità in Germania. Per entrambi, il costo che più influenza la produzione è quello dell’agricoltura. Il risultato è stato confermato dall’analisi di sensibilità. Le conclusioni evidenziano i danni ambientali provocati dal biogas per una produzione di energia elettrica di massa, causati dalle odierne pratiche colturali e gli alti costi per supportarle. Le pratiche agricole dovrebbero essere sviluppati e i costi ridotti, così da rendere l’investimento nel settore biogas sostenibile a livello ambientale e economicamente profittevole.
A life cycle analysis and economic comparison between biogas and natural gas in two different countries : Germany and Italy
PIERI, MONICA ROBERTA
2012/2013
Abstract
The present study analyses the environmental impact of electricity production from two different sources: natural gas and biogas upgraded, the so called bio-methane. Through LCA approach, several indicators are evaluated according to ReCiPe model in GaBi software. The analysis is applied to two different case studies, Germany and Italy, and the perspective is a substitution approach: bio-methane is seen as a valuable bio-fuel compared to natural gas. Our analysis aims to evaluate the impact of the production of 1 kWhel produced by the two technologies. The reasons comes from the Germany contest: its national energy plan, to be complied by 2020, includes decommissioning of nuclear power plants to be substitute by renewables and substitution of natural gas as fuel with bio-methane . LCA methodology was chosen because the study wants to give an overview of all environmental indicators affected by the two technologies, considering emission to water, soil and air. The results show how biogas production significantly affects indicators such as Climate Change, Terrestrial Acidification, Eutrophication, Particulate Matter Formation and Ozone Depletion. Reasons can be found in agricultural practices, emission to air and soil caused by energy crops and their fermentation. Crop yield and transport can vary prominently, thus it affects emissions to air, soil and water in a very variable way. Sensitivity analysis helped to evaluate our assumption and confirmed our results. EU directives for renewable power production and emission reduction are duly taken into consideration. Germany and Italy use different policy to support the improvement of renewable sources, in particular biogas and bio-methane. This last one is currently not supported by Italian Renewable Act. That’s why no bio-methane plant has been installed yet. An overview of the current policies in Germany and Italy is given and an economic analysis is performed. The production cost of bio-methane compared to natural gas in both countries showed lower costs in Germany. We also verified the profitability of a bio-methane plant in Germany. The comparative analysis for biogas power plant in Germany and Italy showed higher profitability in Germany, thanks to the supporting policy. For both bio-methane and biogas the most influencing cost items are the agricultural cost. The result was confirmed by the sensitivity analysis. Conclusions highlight the environmental damages of biogas for massive electricity production, caused by today’s energy crops practices and the high costs to support them. Agricultural practices should be improved and cost reduced to make the investment environmentally sustainable and economically profitable.| File | Dimensione | Formato | |
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https://hdl.handle.net/10589/80544