Samenvatting

One potential renewable energy resource is green gas production through anaerobic digestion (AD). However, only part of the biogas produced (up to 50-60%) contains the combustible methane; the remainder are incombustible gasses with the biggest being carbon dioxide. These gasses are often not used and expelled in the atmosphere. Through the use of BIO-P2M where hydrogen is mixed with the remaining CO2 additional methane can be produced, increasing the yield and using the feedstocks more effectively. Within this research the environmental sustainability and effectiveness of BIO-P2M is evaluated using the MEFA and aLCA method, expressed in; net green gas production, efficiency in (P)EROI, emissions in GWP100, and environmental impact in Ecopoints. The functional unit is set as a normal cubic meter of Groningen quality natural gas. Results indicate a net improvement of all indicators when applying BIO-P2M in several configurations (in situ, ex situ). When allocating the production of renewable energy to the BIO-P2M system environmental impacts for wind the results are still positive; however, when using solar PV as an energy source the environmental impact in Ecopoints exceeds that of the reference case of Groningen natural gas. An additional option for improving the indicators is optimization of the process. When using BIO-P2M combined with heat and power unit for producing the internal electricity and heat demands all indicators are improved substantially. On a national scale when utilizing al available waste materials for the BIO-P2M system around 1217 MNm3/a of green gas can be produced, which is 3% of the total yearly consumption in the Netherlands and around 60% more than when using normal AD systems. Within the context BIO-P2M is an interesting option for increasing green gas output and improving the overall sustainability of the AD process. However, the source of green electricity needs to be taken into account and process optimization can ensure better environmental performance.