Life Cycle Assessment of Biochar Production and Soil Application on Danish Dairy Farms
Authors
Poulsen, Lasse Krogh ; Coenen, Philip Holger Lindholt
Term
4. Term
Publication year
2023
Submitted on
2023-06-01
Pages
80
Abstract
Denne afhandling undersøger, om danske mælkeproducenter kan reducere deres miljøpåvirkninger ved at fremstille biokul via pyrolyse (opvarmning af biomasse uden ilt) og tilføre det til jorden for at lagre kulstof. To typer restbiomasse analyseres som input til pyrolyse: halmrester og afgasset gylle (gylle efter biogasprocessen). Miljøpåvirkningerne blev sammenlignet med en livscyklusvurdering (LCA) i to tilgange: en konsekvensmodel og en model baseret på International Dairy Federation (IDF) retningslinjer for at se, hvordan metodevalg påvirker resultaterne. Forskningsinterviews gav data og praktisk indsigt i pyrolyseprocessen og landbrugskonteksten. I begge modeller og for begge typer biomasse viste LCA'en lavere påvirkninger på global opvarmning og på respiratory inorganics, det vil sige luftforurenende stoffer, der kan skade menneskers sundhed, sammenlignet med at udbringe biomassen direkte på marken uden pyrolyse. Resultaterne blev anvendt på en konkret malkekvægsbedrift for at beregne, hvor meget gårdens tilgængelige biomasse kunne reducere påvirkningerne. Samlet set tyder pyrolyse på at være et nyttigt værktøj til at nedbringe udledninger i mælkeproduktion, men der er behov for mere data, fordi teknologien stadig er ny i kommerciel skala.
This thesis examines whether Danish dairy farms can reduce environmental impacts by making biochar through pyrolysis (heating biomass without oxygen) and applying it to soils to store carbon. It considers two types of residues as feedstocks for pyrolysis: straw residues and digested manure (manure after anaerobic digestion). Environmental impacts were compared using Life Cycle Assessment (LCA) with two approaches: a consequential model and a model based on International Dairy Federation (IDF) guidelines, to see how method choices influence results. Research interviews provided data and practical insight into the pyrolysis process and the farming context. In both models and for both feedstocks, the LCA found lower impacts on global warming and on respiratory inorganics—air pollutants that can harm human health—compared with spreading the biomass directly on fields without pyrolysis. These findings were applied to a specific dairy farm to estimate how much the farm’s available biomass could reduce its impacts. Overall, pyrolysis appears to be a useful tool to cut emissions in dairy farming, but more data are needed because commercial-scale pyrolysis is still new.
[This summary has been rewritten with the help of AI based on the project's original abstract]
Keywords
Dairy ; LCA ; Carbon ; Sequestration ; Carbon storage ; Biochar ; Agriculture ; Pyrolysis ; Milk ; Farm ; Life Cycle Assessment ; GHG ; Emissions ; CO2 emissions
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