Spatial and environmental assessment of energy potentials for Anaerobic Digestion production systems applied to the Netherlands

Anaerobic digestion (AD) can play an important role in achieving the renewable energy goals set within the European Union. Within this article the focus is placed on reaching the Dutch local renewable production goal set for the year 2020 with locally available biomass waste flows, avoiding intensive farming and long transport distances of biomass and energy carriers. The bio-energy yields, efficiency and environmental sustainability are analyzed for five municipalities in the northern part of the Netherlands, using three utilization pathways: green gas production, combined heat and power, and waste management. Literature has indicated that there is sufficient bio-energy potential in local waste streams to reach the aforementioned goal. However, the average useful energy finally produced by the AD production pathway is significantly lower, often due to poor quality biomass and difficult harvesting conditions. Furthermore, of the potential bio-energy input in the three utilization pathways considered in this article, on average: 73% can be extracted as green gas; 57% as heat and power; and 44% as green gas in the waste management pathway. This demonstrates that the Dutch renewable production goal cannot be reached. The green gas utilization pathway is preferable for reaching production goals as it retains the highest amount of energy from the feedstock. However, environmental sustainability favors the waste management pathway as it has a higher overall efficiency, and lower emissions and environmental impacts. The main lessons drawn from the aforementioned are twofold: there is a substantial gap between bio-energy potential and net energy gain; there is also a gap between top-down regulation and actual emission reduction and sustainability. Therefore, a full life cycle-based understanding of the absolute energy and environmental impact of biogas production and utilization pathways is required to help governments to develop optimal policies serving a broad set of sustainable objectives. Well-founded ideas and decisions are needed on how best to utilize the limited biomass availability most effectively and sustainably in the near and far future, as biogas can play a supportive role for integrating other renewable sources into local decentralized energy systems as a flexible and storable energy source. (C) 2016 Elsevier Ltd. All rights reserved

Modeling biogas chains

Within the Flexigas project a model has been constructed which can analyze the efficiency, carbon footprint and environmental impact of anaerobic biogas production chains

Local balancing of the electricity grid in a renewable municipality; analyzing the effectiveness and cost of decentralized load balancing looking at multiple combinations of technologies

With the integration of Intermitted Renewables Energy (I-RE) electricity production, capacity is shifting from central to decentral. So, the question is if it is also necessary to adjust the current load balancing system from a central to more decentral system. Therefore, an assessment is made on the overall effectiveness and costs of decentralized load balancing, using Flexible Renewable Energy (F-RE) in the shape of biogas, Demand Side Management (DSM), Power Curtailment (PC), and electricity Storage (ST) compared to increased grid capacity (GC). As a case, an average municipality in The Netherlands is supplied by 100% I-RE (wind and solar energy), which is dynamically modeled in the PowerPlan model using multiple scenarios including several combinations of balancing technologies. Results are expressed in yearly production mix, self-consumption, grid strain, Net Load Demand Signal, and added cost. Results indicate that in an optimized scenario, self-consumption of the municipality reaches a level of around 95%, the total hours per year production matches demand to over 90%, and overproduction can be curtailed without substantial losses lowering grid strain. In addition, the combination of balancing technologies also lowers the peak load to 60% of the current peak load in the municipality, thereby freeing up capacity for increased demand (e.g., electric heat pumps, electric cars) or additional I-RE production. The correct combination of F-RE and lowering I-RE production to 60%, ST, and PC are shown to be crucial. However, the direct use of DSM has proven ineffective without a larger flexible demand present in the municipality. In addition, the optimized scenario will require a substantial investment in installations and will increase the energy cost with 75% in the municipality (e.g., from 0.20€ to 0.35€ per kWh) compared to 50% (0.30€ per kWh) for GC. Within this context, solutions are also required on other levels of scale (e.g., on middle or high voltage side or meso and macro level) to ensure security of supply and/or to reduce overall costs

Extreme events in the European renewable power system:Validation of a modeling framework to estimate renewable electricity production and demand from meteorological data

With the need to reduce greenhouse gas emissions, the coming decades will see a transition of Europe's power system, currently mainly based on fossil fuels towards a higher share of renewable sources. Increasing effects of fluctuations in electricity production and demand as a result of meteorological variability might cause compound events with unforeseen impacts. We constructed and validated a modeling framework to examine such extreme impact events on the European power system. This framework includes six modules: i) a reservoir hydropower inflow and ii) dispatch module; iii) a run-of-river hydropower production module; iv) a wind energy production module; v) a photovoltaic solar energy production model; and vi) an electricity demand module. Based on ERA5 reanalysis input data and present-day capacity distributions, we computed electricity production and demand for a set of European countries in the period 2015–2021 and compared results to observed data. The model captures the variability and extremes of wind, photovoltaic and run-of-river production well, with correlations between modelled and observed data for most countries of more than 0.87, 0.68 and 0.65 respectively. The hydropower dispatch module also functions well, with correlations up to 0.82, but struggles to capture reservoir inflows and operating procedures of some countries. A case study into the meteorological drivers of extreme events in Sweden and Spain showed that the meteorological conditions during extreme events selected by the model and extracted from observational data are similar, giving confidence in the application of the modeling framework for (future changes in) extreme event analysis.</p

The big picture:the future role of gas

There are a plethora of drivers of change in energy systems until 2015. The role of social and political actors is likely to be more noticeable. In Europe, locally, high-impact ideas like green consumerism and limited acceptance of energy systems that result in trade-offs will be important. Nationally, the empowerment of individuals and communities and the politicization of energy-related issues will be drivers of change. Internationally, energy issues will become more important in the foreign and security policies of state and non-state actors

Emergency repair of inguinal hernia in the premature infant is associated with high direct medical costs

_Purpose:_ Inguinal hernia repair is frequently performed in premature infants. Evidence on optimal management and timing of repair, as well as related medical costs is still lacking. The objective of this study was to determine the direct medical costs of inguinal hernia, distinguishing between premature infants who had to undergo an emergency procedure and those who underwent elective inguinal hernia repair. _Methods:_ This cohort study based on medical records concerned premature infants with inguinal hernia who underwent surgical repair within 3 months after birth in a tertiary academic children’s hospital between January 2010 and December 2013. Two groups were distinguished: patients with incarcerated inguinal hernia requiring emergency repair and patients who underwent elective repair. Real medical costs were calculated by multiplying the volumes of healthcare use with corresponding unit prices. Nonparametric bootstrap techniques were used to derive a 95 % confidence interval (CI) for the difference in mean costs. _Results:_ A total of 132 premature infants were included in the analysis. Emergency surgery was performed in 29 %. Costs of hospitalization comprised 65 % of all costs. The total direct medical costs amounted to €7418 per premature infant in the emergency repair group versus €4693 in the elective repair group. Multivariate analysis showed a difference in costs of €1183 (95 % CI −1196; 3044) in favor of elective repair after correction for potential risk factors. _Conclusion:_ Emergency repair of inguinal hernia in premature infants is more expensive than elective repair, even after correction for multiple confounders. This deserves to b