1,721,142 research outputs found
Simulation and validation of a Power-to-Power system with hydrogen storage in microporous adsorbent materials
No full textFeasibility Analysis of a Multi-family House Energy Community in Italy
Full text linkThe future energy sustainability largely depends on what will happen in metropolitan cities, therefore the role of the buildings sector and the engagement of citizens in the energy transition will be fundamental. These two dimensions seem to find the perfect match in the so-called energy communities, a group of people that choose to share their energy choices, fluxes and costs, promoting self-consumption configurations. The present paper aims to investigate the energy and economic feasibility of the smallest scale of an energy community: the multi-family house (MFH). Firstly, being these communities an emerging concept, a review of the Italian regulation framework was conducted, to highlight its limits and potentialities. Then, the installation of a community PV plant on the roof of the building was considered for an MFH case study located in the North-West of Italy. The financial convenience of belonging to an energy community was demonstrated through energy and economic evaluation and the definition of specific indicators. Results show that, if the MFH consumers join the community, the economic savings on the energy bill will amount to 40% with respect to the reference case
Optimizing green hydrogen production from wind and solar for hard-to-abate industrial sectors across multiple sites in Europe
Full text linkThis article analyzes a power-to-hydrogen system, designed to provide high-temperature heat to hard-to-abate industries. We leverage on a geospatial analysis for wind and solar availability and different industrial demand profiles with the aim to identify the ideal sizing of plant components and the resulting Levelized Cost of Hydrogen (LCOH). We assess the carbon intensity of the produced hydrogen, especially when grid electricity is utilized.
A methodology is developed to size and optimize the PV and wind energy capacity, the electrolyzer unit, and hybrid storage, by combining compressed hydrogen storage with lithium-ion batteries. The hydrogen demand profile is generated synthetically, thus allowing different industrial consumption profiles to be investigated.
The LCOH in a baseline scenario ranges from 3.5 to 8.9 €/kg, with the lowest values in wind-rich climates. Solar PV only plays a role in locations with high PV full-load hours. It was found that optimal hydrogen storage can cover the users’ demand for 2–3 days.
Most of the considered scenarios comply with the emission intensity thresholds set by the EU. A sensitivity analysis reveals that a lower variability of the demand profile is associated with cost savings. An ideally constant demand profile results in a cost reduction of approximately 11 %
Indirect evidence of hormone abuse. Proof of doping?
No full textBesides anabolic steroids, the most common performance-enhancing hormones are erythropoietin (EPO), insulin, GH, and gonadotropins, mostly indistinguishable from endogenous hormones and with very short half-life. This makes virtually impossible to demonstrate their use by measuring their concentration in the blood or urine. A possible approach to the problem may lie in in-direct demonstration through detection of the biological effects of these substances. The finding of an increased hematocrit level is suspicious but not clearly demonstrative of EPO abuse. Very high levels of circulating EPO could be associated with a strong suspicion of doping, when associated to other abnormal parameters, such as Ht, sTFRr, EPO, RDW. The presence of antibodies against the polysaccharide fraction of lateral chains of EPO has been observed only in patients treated with rhEPO. Owing to the pulsatile pattern of GH, particularly during physical exercise, pathologically high values may be found in normal subjects. Therefore, as in the case of EPO, evidence of GH abuse can be gathered only indirectly by detecting the biological effects of its administration. In training subjects GH treatment increased GH, IGF-I, IGFBP-3 and ALS, and decreased IGBP-2. After cessation of treatment IGF-I, IGFBP-3 and ALS approached basal values between 49 and 96 h. Also the bone parameters PICP ICIP, PIUP and osteocalcin increased significantly. Four days after cessation of treatment, levels of PIIIP and ICTP were still abnormally elevated. In conclusion, increases in IGF-I, IGFBP-3, ALS, PIIIP and ICTP are all indicative of recent GH abuse or of acromegaly
Pre-surgical treatment with somatostatin analogues in patients with acromegaly: The case for
No full textProfitability of energy arbitrage net profit for grid-scale battery energy storage considering dynamic efficiency and degradation using a linear, mixed-integer linear, and mixed-integer non-linear optimization approach
Full text linkGrid-scale energy storage is becoming an essential element to effectively support the rapid increased use of renewable energy sources in the power network. The present work proposes a long-term techno-economic profitability analysis considering the net profit stream of a grid-level battery energy storage system (BESS) performing energy arbitrage as a grid service. The net profit is a cost function that includes the revenue derived by arbitrage, the import cost and the degradation cost induced by battery capacity fade. Three optimization techniques with a computationally efficient optimization logic are developed. The scenario with no-degradation is formulated as a linear programming (LP) problem, while the scenarios with and without degradation are formulated as mixed-integer linear programming (MILP), and as mixed-integer non-linear programming (MINLP) problems. The non-linearity is introduced by implementing a BESS dynamic charge/discharge efficiency that is a function of the BESS power rate. Based on the obtained BESS optimal scheduling, a long-term profitability analysis is developed during the whole BESS lifetime. In the proposed case study, historical electricity market prices from the CAISO electricity market in the United States, California, are used as input. We found that, even without degradation, the break-even investment cost that makes the BESS profitable with a power to-energy-ratio of 1MW/2MWh is 210 $/kWh. By implementing a cycle-counting degradation model, we observed a remarkable battery degradation on BESS profitability corresponding to a yearly net profit reduction in the 13-24% range. From a long-term application perspective, the BESS calendar lifetime could be extended by reducing the battery cycling. Such cycling reduction is obtained by adding a penalty cost in the objective function of the energy arbitrage optimization problem
Optimal Energy Management of a Utility-Scale Battery Energy Storage System Integrated with a Photovoltaic Power Plant Considering Battery Degradation
No full textGrid-scale energy storage systems are becoming an essential element to effectively support the rapid increased use of renewable energy sources in the power network. An energy management system (EMS) is essential to optimize the energy dispatching operations by controlling the operating point of each of the system components. The present work proposes an optimal scheduling for an EMS of a utility-scale photovoltaic power plant (PV) coupled with a battery energy storage system (BESS). The EMS model is based on a computationally efficient optimization logic formulated as a mixed-integer linear programming (MILP) problem. In the proposed case study, PV hourly generation data and historical electricity market prices from the CAISO electricity market in the United States, California, are used as input. The achievable profit from energy arbitrage of PV plus BESS systems is determined considering the impact of battery degradation
Effect of short-term treatment with low dosages of the proton-pump inhibitor omeprazole on serum chromogranin A levels in man.
No full textBACKGROUND:
Measurement of chromogranin A (CgA) levels in blood can be used to monitor neuroendocrine tumors (NETs). CgA levels may also be elevated in several other endocrine and non-endocrine diseases. It is well known that drugs affecting acid gastric secretion can increase gastrin. Proton-pump inhibitors are extensively used but only a few data have been reported on their effects on CgA secretion.
DESIGN:
The aim of the study was to evaluate the short-term effect of low dosages of omeprazole (OM) on CgA levels and to sensitize endocrinologists to possible false positive values of CgA in order to prevent expensive diagnostic work-up in searching for NETs.
SUBJECTS AND METHODS:
Thirty-five female and nine male in-patients (18-81 years) were studied. Mild or severe hypertension in 20 patients needed therapy. Endocrine and metabolic diseases were diagnosed in the majority of patients. CgA levels were evaluated before and during OM therapy (10 mg/day, orally).
RESULTS:
Without OM therapy, CgA levels were 64+/-6 microg/l. Elevated baseline CgA levels were found in nine subjects. CgA levels were significantly related to age (P<0.001), creatinine levels (P=0.03) and the severity of hypertension (P=0.002). On short-term OM therapy (n=42; 18.8+/-2.4 days; range 5-90 days) a significant (P<0.001) increase in CgA (145+/-22 microg/l) from baseline (63+/-7 microg/l) levels was found. The average net CgA increase on short-term OM therapy was 93+/-20 microg/l. There was a significant correlation between baseline CgA levels and CgA increase on short-term OM therapy (P=0.004) but not between the increase in CgA and the duration of the therapy.
CONCLUSIONS:
An increase in CgA levels quickly follows the start of low dosages of OM. This release is more pronounced when the baseline CgA levels are already increased by slight renal insufficiency or severe hypertension. In this common clinical situation an intensive work-up for NETs is not justified before reassessment of CgA after the withdrawal of OM
Model complexity and optimization trade-offs in the design and scheduling of hybrid hydrogen-battery systems
Full text linkThe production of hydrogen from renewable sources could play a significant role in supporting the transition toward a decarbonized energy system. This study has involved investigating optimization strategies - mixed-integer linear programming (MILP), a hybrid particle swarm optimization (PSO)-MILP framework, and PSO combined with a rule-based energy management strategy (EMS) - applied to a power-to-hydrogen system for industrial applications. The analysis evaluates the levelized cost of hydrogen production (LCOH), carbon emissions, and the impact of key factors, such as battery degradation, electrolyzer efficiency, real-time pricing, and hydrogen load management. The obtained results indicated that the MILP-based models achieved moderate LCOH values (10.1-10.7 €/kg) but incurred higher CO2 emissions (20.2-24.6 kt/y). Instead, the PSO model, combined with the rule-based EMS, lowered emissions to 14.3 kt/y (a 27-45% reduction), albeit with a higher LCOH (11.6 €/kg). The hybrid PSO-MILP models struck a balance, achieving LCOH values of between 9.2 and 9.7 €/kg, with CO2 emissions of 19.7-20.3 kt/y, as they benefited from the integration of piecewise affine linearization for modeling electrolyzer efficiency and battery degradation. In terms of computational efforts, the MILP-based models required more than 48 h to converge, while the PSO-MILP models completed within 27-35 h, and the PSO model with rule-based EMS achieved results in 1.5 h. These findings offer guidance that can be used to select the most suitable optimization method on the basis of the desired performance targets, resource constraints, and computational complexity, thereby contributing to the design of more sustainable energy systems
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