ALBERT

Description: The aim of the present paper is to develop a reliable and accurate model of the wastewater biochemical treatment process and to explore the behaviour through a general dynamic simulation environment, namely the INtegrated Simulation Environment Language (INSEL), for the analysis of the energy demand of the whole wastewater treatment plant. In particular, the presented model pays special attention to the chemical kinetics involved in the activated sludge process for the reduction of nitrogen and carbon compounds. According to the best practices, the plant configuration considered in this work includes the denitrification-nitrification process, performed by completely mixed reactors. In particular, the process analysed in this paper is based on the Ludzak-Ettinger process. The biological process is simulated according to the well-known method widely used in the literature, namely the Activated Sludge Model No 1 (ASM1). The model includes a set of equations for the calculation of aerobic growth of heterotrophs, anoxic growth of heterotrophs, aerobic growth of autotrophs, decay of autotrophs, ammonification of soluble nitrogen, hydrolysis of entrapped organics, and hydrolysis of entrapped organic nitrogen. All these equations, along with energy and mass balances, are solved by the explicit Euler method. The developed model is validated using literature data, showing a great accuracy (deviation below 1%). As for the temperature, results show that, between 15 and 25 °C, in the initial part of the process, transport effects dominate the consumption ones. When the temperature is higher than 30 °C, nitrate consumption is so fast that biomass growth is limited by this effect. Conversely, in case of low temperatures (5–10 °C), biomass growth is not limited by nitrate availability. Finally, results also showed that temperature significantly affects the denitrification process, whereas the effect on the oxygen is lower.

Description: Innovative small-scale biogas plants, including upgrading solutions to affordable biomethane, are necessary to tap into the spatially distributed potentials of organic waste. This research identified and assessed novel small-scale technologies before market-entry maturity in the key process steps of the biomethane chain. We assessed technical, economic, and ecological indicators, and compared them to larger-scale references. The assessment included 7 pre-treatment, 13 digester, and 11 upgrading systems all at the small scale. We collected recently available data for Europe (2016–2018) for small-scale technologies (

Description: Natural gas covers more than 20% of Europe’s primary energy demand. A potential disruption could lead to supply shortages with severe consequences for the European economy and society. History shows that such a vast and complex network system is prone to exogenous and endogenous disruptions. A dedicated large-scale dataset of the European natural gas network from publicly available information sources is assembled first. The spatial coverage, completeness and resolution allows analyzing the behavior of this geospatial infrastructure network (including consumption) and its components under likely disruptive events, such as earthquakes, and/or technical failures. Using the developed system state simulation engine, the disruption impact is mapped. The results show that storage facilities cannot in all cases compensate for a pipeline disruption. Moreover, critical pipelines, such as the Transitgas pipeline crossing the Alps and the Trans-Mediterranean pipeline bringing natural gas from Northern Africa, are identified. To analyze the pipelines with high impact on the system performance, a detailed scenario analysis using a Monte Carlo simulation resulting in supply grade mapping is conducted and presented for the case of Italy. Overall, it can be concluded that locations with a dead-end, sole supply, and without storage facility nearby, are remarkably exposed to natural gas supply losses.

Description: In order to calculate the financial return of energy efficiency measures, a cost–benefit analysis (CBA) is a proven tool for investors. Generally, however, most CBAs for investors have a narrow focus, which is—simply speaking—on investment costs compared with energy cost savings over the life span of the investment. This only provides part of the full picture. Ideally, a comprehensive or extended CBA would take additional benefits as well as additional costs into account. The objective of this paper is to reflect upon integrating into a CBA two important cost components: transaction costs and energy efficiency services—and how they interact. Even though this concept has not been carried out to the knowledge of the authors, we even go a step further to try to apply this idea. In so doing, we carried out a meta-analysis on relevant literature and existing data and interviewed a limited number of energy experts with comprehensive experience in carrying out energy services. Even though data is hardly available, we succeeded in constructing three real-world cases and applied an extended CBA making use of information gathered on transaction costs and energy services costs. We were able to show that, despite these additional cost components, the energy efficiency measures are economically viable. Quantitative data was not available on how energy services reduce transaction costs; more information on this aspect could render our results even more positive. Even though empirical and conceptual research must intensify efforts to design an even more comprehensive CBA, these first-of-its-kind findings can counterargue those that believe energy efficiency is not worth it (in monetary terms) due to transaction costs or energy services costs. In fact, this is good news for energy efficiency and for those that seek to make use of our findings to argue in favor of taking up energy efficiency investments in businesses.