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Background: New regulations and market conditions in Germany affect the profitability of biomethane upgrading as a repowering option for existing biogas plants following on-site CHP utilization. These conditions present trade-off challenges between higher sustainability requirements, maintaining production capacity and new revenue opportunities. Optimization methods, such as linear programming (LP), are essential for determining the ideal substrate mixture and profitable solutions amidst multiple market conditions, plant-specific process constraints, and substrate properties. Methods: We updated a substrate mixture optimization model within an assessment framework for the repowering of existing biogas plants (BGPs), which focuses on the operator's perspective. By integrating multiple German biomethane markets for various BGPs, we assessed changes in the substrate mixture, GHG emissions, contribution margins, and constraint parameters to derive conclusions for operators and future framework design. Results: Integrating market revenues and constraints can increase contribution margins by 12–55%. Additional gains can be achieved by considering multiple markets simultaneously but limited to a few BGPs. The plant-specific LP solution space and used benchmark market are decisive. The former limits the potential of high substrate-specific contribution margins, which has a significantly higher impact than the relation between plant-specific characteristics and process constraints. The advanced fuel market is currently the lead market for biomethane, incentivizing GHG-emission extensive substrates, decreasing gas production and GHG emissions but increasing levelized cost of energy (LCOE) and partially CO2 abatement costs. Conclusions: The key to improve profitability and to supply an increasing biomethane demand while fulfilling new requirements is a large LP solution space. Increasing market options, substrate availability, and digestion system capacity achieve this on the operator's side. Policy makers could reduce normative requirements such as the maize cap or double counting of advanced fuels and favor high but uniform GHG requirements. Operators can prepare robustly for the future substrate mixture by adding digester volume and pre-treatment tech, ensuring long-term and diverse substrate availability, and contracts with flexible components. Although current market conditions can improve specific GHG emissions, they do not necessarily increase manure usage when other options, such as straw, are viable. Other regulatory support systems will be required to do so. [ABSTRACT FROM AUTHOR]

Due to the decarbonization of the energy system, natural gas will only play a minor role as an energy source after 2045. To decarbonize the gas supply in the future, there are two options for green gases: hydrogen or biomethane. The injection of green gases into the existing gas infrastructure leads to changes in the gas composition, requiring a consideration of the framework conditions for distribution. Adjustments to the grid for transport may be required. Consequently, this paper presents the main characteristics of hydrogen and biomethane and examines the suitability of the gas infrastructure for their transportation. A case study for the development of gas infrastructure in Germany is presented. The focus is on the further development of biogas, concentrating on the question of which biogas should optimally be upgraded in the future to enable its be distribution in the long term. [Display omitted] • Dedication of gas infrastructure to hydrogen in competition with the distribution of biomethane. • Examination of the suitability of the infrastructure for the distribution of green gases. • Gas grid development pathways in Germany. • Role of biogas in future gas supply. [ABSTRACT FROM AUTHOR]

Wind and solar power are already the major pillars of renewable power generation in Germany and will become even more dominant in the future. At the same time, dispatchable power plants phasing out. The expected increase of fluctuations in the residual load could be partial balanced by flexible bioenergy. However, there is currently no assessment approach for quantifying the systemic GHG impacts for flexible bioenergy generation. Based on the merit order concept, we develop an empirical approach to systemically assess the GHG emissions impact for electricity generated by flexible bioenergy plants. We estimate price response functions using the historical data of market prices and feed-in time series for the different forms of dispatchable non-renewbale dispatchable generation (NRDG). By calculating the expected NRDG based on these functions, and using specific emission factors, we are able to estimate the net impact for a switch from invariable to flexible bioenergy generation. The calculated net impact ranges from −20 to −36 g CO 2eq per kWh, which is equivalent to a benefit of −10% to −18% respectively for an average carbon footprint of 200 g CO 2eq per kWh. The calculation tools are written in Python and freely accessible on ZENODO and GitLab. [Display omitted] [ABSTRACT FROM AUTHOR]

The study presents the development of a method for the long term monitoring of methane emissions from pressure relief valves (PRV 1 PRV: pressure relief valve. 1 ) of biogas storages, which has been verified during test series at two PRVs of two agricultural biogas plants located in Germany. The determined methane emission factors are 0.12 g CH 4 kWh el −1 (0.06% CH 4 -loss, within 106 days, 161 triggering events, winter season) from biogas plant A and 6.80/7.44 g CH 4 kWh el −1 (3.60/3.88% CH 4 -loss, within 66 days, 452 triggering events, summer season) from biogas plant B. Besides the operational state of the biogas plant (e.g. malfunction of the combined heat and power unit), the mode of operation of the biogas flare, which can be manually or automatically operated as well as the atmospheric conditions (e.g. drop of the atmospheric pressure) can also affect the biogas emission from PRVs. [ABSTRACT FROM AUTHOR]

Abstract: Increasing shares of intermittent power sources such as solar and wind will require biomass fueled generation more variable to respond to the increasing volatility of supply and demand. Furthermore, renewable energy sources will need to provide ancillary services. Biogas plants with excess generator capacity and gas storages can adapt the unit commitment to the demand and the market prices, respectively. This work presents a method of day-ahead unit commitment of biogas plants with excess generator capacity and gas storage participating in short-term electricity and control reserve markets. A biogas plant with 0.6 MW annual average electric output is examined in a case study under German market conditions. For this biogas plant different sizes of the power units and the gas storage are compared in consideration of costs and benefits of installing excess capacity. For optimal decisions depending on prices, a mixed-integer linear programming (MILP) approach is presented. The results show that earnings of biogas plants in electricity markets are increased by additional supplying control reserve. Furthermore, increasing the installed capacity from 0.6 MW to 1 MW (factor 1.7) leads to the best cost–benefit-ratio in consideration of additional costs of excess capacity and additional market revenues. However, the result of the cost–benefit-analysis of installing excess capacity is still negative. Considering the EEG flexibility premium, introduced in 2012 in the German renewable energy sources act, the result of the cost–benefit-analysis is positive. The highest profit is achieved with an increase of the installed capacity from 0.6 MW to 2 MW (factor 3.3). [Copyright &y& Elsevier]

This article deals with the analysis of instrumentation from three modern German full-scale biogas plants with different inputs and typical process engineering concepts for German conditions. The measured results from each plant and the suitability of the instrumentation used are evaluated and assessed. Conclusions are also made about improving the use and architecture of the instrumentation. The analysis results show which benefits and optimum combination of on-line and off-line instrumentation could result for the control and automation of industrial and agricultural biogas plants. [ABSTRACT FROM AUTHOR]

This paper give information about German biogas plant at middle and big scale. That research was executed with support of Rostock University and Hohenheim University. The main objective is to show the properties of German biogas plant at middle and big scale and it's possible use in undevelopment country like as Cuba. [ABSTRACT FROM AUTHOR]