Unlocking the biomethane potential of bovine manure? A cost-benefit analysis and geospatial assessment of biomethane production on medium-sized Dutch dairy farms

Abstract

Greenhouse gas emissions and environmental pollution from the energy and dairy farming sector must decrease to achieve sustainability goals in the Netherlands. Manure digestion (MD) and nitrogen stripping (NS) can contribute to both. With MD, CH4 emissions are captured from slurry. The CH4 is useable for biomethane production, a substitute for natural gas. The residual product, digestate, can be used for NS, which decreases ammonia emissions. MD and NS have thus far mostly been economically viable for relatively large dairy farms. This thesis researched the economic and practical viability of MD, potentially complemented by NS, if operated by groups of one to ten small or medium-sized Dutch dairy farms. Based on the findings, MD is not economically viable for such groups without NS. Digesting manure on each individual farm demands substantial investments. Digesting manure at a central location demands daily transports of fresh slurry, which for small farms is difficult to realize daily. With NS, MD is viable for groups with 800 to 1100 dairy cows in total. However, the added value of NS strongly depends on the manure disposal price. An analysis of the current geospatial distribution of Dutch dairy farms indicated that the economic potential of slurry-based biomethane ranges from 0,22 to 0,48 bcm. Several major practical obstacles for manure-based biomethane production in groups, most notably permit acquirement, complicate the realization of this potential in the near future.