Wim Bijkerk, student of the VU University of Amsterdam, completed his BSc thesis within the BiogasETC project in July 2013.
The thesis report is entitled: ‘Energizing the countryside, the optimal utilization of small scale gas upgrading at farm sites’
Dr. René Cornelissen of CCS has acted as Internship coach; 1st assessor was J.A. Neijzen; 2nd assessor was J.P. Dekker.
Summary of the report:
Biogas can be obtained through the digestion of organic waste flows, which provides several advantages. The produced biogas is a sustainable source of energy and reduces the emission of greenhouse gasses, without ending up in the food vs. fuel dilemma. Additional benefits of biomethane, a biogas derived natural gas substitute, is that waste flows yield a valuable product, which can be integrated in the Dutch energy supply very well. Biomethane can play an essential part in the energy transition, because the biogas production is more predictable and controllable than the wind and solar energy production.
Biogas production suits the agricultural sector very well, because agriculture, especially farming, produces large quantities of waste and contributes significantly to the emission of harmful greenhouse gasses. This combination creates opportunities to make the sector more sustainable, without emplacing restraints or limitations on everyday practice. The most suitable for small scale biogas production are farms with relatively large waste flows and a need for fertilizers on pastures. These conditions can be found best at Dutch dairy farms.
The utilization of the produced biogas is an important factor in small scale biogas production. Nowadays nearly all biogas is used to produce heat and power in CHP-units. The low efficiencies and the lack of a sufficient nearby heat demand constrain the usability of this method. In order to overcome these two drawbacks, Cornelissen Consulting Services B.V. is developing a small scale gas upgrading plant to produce biomethane from biogas. Gas upgrading isn’t hindered by the large dissipation of usable energy. The developed installation uses an innovative scrubbing agent, which removes CO2 and H2S simultaneously from the biogas, whereby methane losses are zero.
There are definitely opportunities for small scale biomethane production at farm sites. Biomethane production can be an additional source of revenue, directly though the sales of biomethane and, eventually, indirectly though the induced possibilities, e.g. waste processing. Regardless of any financial benefits, the production of biomethane yields large environmental benefits. One digester and upgrading plant at a dairy farm will reduce GHG-emissions with 346.3 tCO2e/year.
Calculations based on the current tailored plant design and the development up to this point; indicate that small scale upgrading is not yet feasible. The overall design of the installation as well as the scrubbing agent have to be improved. Calculations based on batch production, better heat integration and a more stable scrubbing agent; a future vision indicates a sound and solid case is achievable. The estimated €400,000 investment has a payback time of 6.3 years and the NPV of the project is €64,000 at a 15% discount rate.
This future vision can be achieved through focusing on two key aspects. The first aspect is the design of the plant. Enhancements have to be made to reduce energy and financial losses; key points of interests are the durability of the scrubbing agent, heat integration and a robust design. The second aspect is the valorization of the triggered non-financial benefits, like reduction of GHG’s and manure processing.