This study addresses the increasing need for flexibility in the Polish Power System (PPS), particularly in the context of growing price volatility on the Day-Ahead Market (DAM) resulting from the rising share of renewable energy sources (RESs). The aim of the study was to assess the feasibility of implementing demand-driven operation in an existing linear biogas plant in Poland and to develop a Decision-Making Model (DMM) for optimizing its operation based on electricity price forecasts. A machine learning model based on Extreme Gradient Boosting (XGBoost) was developed using historical electricity price, demand and weather data and integrated into the DMM to generate hourly operating schedules. The model achieved high predictive accuracy, with a Mean Absolute Error (MAE) of approximately 51 PLN/MWh, and effectively captured nonlinear price dynamics. Based on predefined decision thresholds—biogas production rate, current biogas storage level, upper and lower limits of pressure in biogas storage capacity, maximum biogas storage duration, power quotient (PQ) and electricity price levels—optimal operating strategies were determined. The results indicate that while demand-driven operation is technically feasible and enables better alignment with market signals, its economic viability remains limited under current market and regulatory conditions. Investment in additional cogeneration capacity was not justified, as costs significantly exceeded potential revenues. Consequently, a more viable approach involves optimizing existing infrastructure through flexible production strategies.

In their study, the authors analyse the changes made to the Renewable Energy Sources Act with regard to guarantees of origin, in relation to the implementation of the RED II Directive. In the first part of the study, they describe the EU regulations introducing guarantees of origin as a document certifying to the end user that a given part or quantity of energy was produced from renewable sources. They then turn to the changes concerning the new energy carriers covered by guarantees of origin. In this regard, they analyse these carriers with reference to French and German regulations. They describe the procedure for obtaining guarantees of origin, pointing to the significant differences in the French system. The last part of the paper is devoted to the mutual recognition of guarantees of origin and Poland’s participation in the Association of Issuing Bodies.

The authors analyse the changes made to Poland's Renewable Energy Sources Act regarding the support system for biomethane, in relation to the implementation of the RED II Directive and the EU hydrogen and gas decarbonisation package. In the first part of the study, they describe the basis of pro-environmental, sector-specific regulation, particularly in the gas industry, and the potential for using biomethane to decarbonise this sector. They then analyse changes in European policy and legislation relating to biomethane, as set out in the Polish National Energy and Climate Plan. The final section of the paper focuses on the key instrument for supporting biomethane in Poland: the sale of biomethane at a fixed purchase price. In this regard, they analyse the legal framework for this instrument, the procedure for obtaining support, the level of the fixed purchase price, the support period, and the rules for settling accounts with the entity paying the state aid.