Unit commitment and investment valuation of flexible biogas plants in German power markets

Biogas plants become more flexible, scheduling their power generation with respect to market prices. For this purpose the electrical capacity of power units is extended to convert the continuously produced gas as well as the gas held in storage. This work has shown how gas plants with extended capacity located at a gas production site can be analyzed on the basis of unit commitment. Mixed integer linear programs (MILP) have been developed for the unit commitment of such plants in different use cases. The models developed consider gas plants at a gas production site participating in German power markets, switching between static and variable gas supply, providing secondary and tertiary control reserve, and claiming the German market and flexibility premium. The models can be applied to plan daily schedules for the operation of these gas plants. Furthermore, the models can be applied to analyze the benefits of extending the electrical or storage capacity of gas plants located at a gas production site. The models calculate the optimized gross income that can be applied as cash flow for determining the net present value (NPV) of investments in extended electrical and storage capacity.