Research paperFeedstock change at biogas plants - Impact on production costs

- Scenarios of operational changes in the feedstock composition are developed.
- The economic analysis considers adaptations and incremental investments of biogas plants.
- Prior processing of raw material leads to a substantial increase of costs.
- The utilization of alternative feedstocks increases the overall production costs.
- Environmental pay-offs could be encouraged through appropriate subsidy.

At the beginning of the millennium, regulatory changes relating to energy production from biogas triggered a significant increase in the installation of biogas plants in Europe. During the past few years, the regulatory framework has been adapted to accommodate biogenic waste and agricultural residues as a primary source of raw materials.Based on individual data of Austrian biogas plants, this article performs a detailed costs assessment in case of feedstock changes. Various scenarios of possible agricultural raw material changes are examined assuming a base scenario of a 500 kW biogas plant feed with a mix of maize silage and slurry. The presented technical and economic analysis focuses on the scenarios “mix”, “manure”, “stover/catch crops”, and “second crops”. The results show that the use of alternative feedstocks has only limited effects on the cost of feedstock procurement as the advantage of lower specific costs is counter-balanced by the need for higher quantity. The substantial technical efforts and additional investments negatively impact the cost of biogas production, resulting in an average cost increase of 30%.