Investment in wind-based hydrogen production under economic and physical uncertainties

This paper evaluates the economic viability of a combined wind-based green-hydrogen facility from an investor's viewpoint. The paper introduces a theoretical model and demonstrates it by example. The valuation model assumes that both the spot price of electricity and wind capacity factor evolve stochastically over time; these state variables can in principle be correlated. Besides, it explicitly considers the possibility to use curtailed wind energy for producing hydrogen. The model derives the investment project's net present value (NPV) as a function of hydrogen price and conversion capacity. Thus, the NPV is computed for a given price and a range of capacities. The one that leads to the maximum NPV is the ‘optimal’ capacity (for the given price). Next, the authors estimate the parameters underlying the two stochastic processes from Spanish hourly data. These numerical estimates allow simulate hourly paths of both variables over the facility's expected useful lifetime (30 years). According to the results, green hydrogen production starts becoming economically viable above 3 €/kg. Besides, it takes a hydrogen price of 4.7 €/kg to reach an optimal conversion capacity half the capacity of the wind park. The authors develop sensitivity analyses with respect to wind capacity factor, curtailment rate, and discount rate. © 2023 The Author(s)This research is supported by the Spanish Ministry of Economy and Competitiveness (MINECO), through BC3 María de Maeztu excellence accreditation MDM-2017-0714, and the Basque Government (IT1777-22, Grupo de Investigación del Sistema Universitario Vasco, Grupo B). Further support is provided by Fundación Repsol through the Low Carbon Programme joint initiative (http://www.lowcarbonprogramme.org). The authors thank seminar participants at the 17th IAEE European Energy Conference (Athens, September 2022) for their helpful comments. We also thank three anonymous referees for their thorough, helpful remarks and suggestions. The authors remain responsible for any errors. This research is supported by the Spanish Ministry of Economy and Competitiveness (MINECO), through BC3 María de Maeztu excellence accreditation MDM-2017-0714, and the Basque Government (IT1777-22, Grupo de Investigación del Sistema Universitario Vasco, Grupo B). Further support is provided by Fundación Repsol through the Low Carbon Programme joint initiative (http://www.lowcarbonprogramme.org). The authors thank seminar participants at the 17th IAEE European Energy Conference (Athens, September 2022) for their helpful comments. We also thank three anonymous referees for their thorough, helpful remarks and suggestions. The authors remain responsible for any errors. Data availability. The authors have drawn on the database of the Spanish power transmission and distribution system operator (Red Eléctrica de España), which is publicly available: https:/www.esios.ree.es

A multi-resolution and multivariate analysis of the dynamic relationships between crude oil and petroleum-product prices

This paper proposes the use of a novel multivariate, dynamic approach wavelet local multiple correlation (WLMC) (Fernández-Macho, 2018) to analyse the relationship between oil time series in the time-scale domain. This approach is suitable for use with energy data of any kind that change over time and involve heterogeneous agents who make decisions across different time horizons and operate on different time scales. The study of the links between multivariate oil time series is of great importance in energy research, e.g., it is extremely important for petroleum industry refiners and investors to know the relationships and margins between output prices and crude oil costs. The estimation of wavelet correlations in a multivariate framework between such prices is a suitable way to analyse crude oil and petroleum products as a system. To exemplify the use of WLMC, we analyse the relationships between the prices of seven commodities: West Texas Intermediate crude oil and six distilled products (conventional gasoline, regular gasoline, heating oil, diesel fuel, kerosene and propane) from 10/06/2006 to 17/01/2017. The results reveal that the wavelet correlations are strong throughout the period studied and there is a strong decay in correlation values from 2013 to 2015. The most plausible explanation for this decay is overproduction of tight oil in the U.S. and a slowdown in global demand for oil. Furthermore, our results also reveal that heating oil, diesel and kerosene maximise the multiple correlation with respect to the other oil variables on different scales, indicating that these products are the most dependent variables in the crude-product/price system. WLMC offers new opportunities for applications in energy research and other fields. © 2018 Elsevier Lt

On flexible hydropower and security of supply: Spain beyond 2020

Generation adequacy is a key ingredient to security of electricity supply (SoS). Some national plans envisage a future decrease in the number of coal-fired stations and an increase in renewable installed capacity. This forecast, along with the future reduction of nuclear capacity, will lead to a combination of less baseload plants and sizeable intermittent generation. Hence there is a risk that supply will be unable to meet demand and generation adequacy will suffer. We assess how the flexible management of hydro resources can alleviate this risk by adjusting power generation to peak demand. Indeed there is empirical evidence that they are positively correlated. We compute this correlation in the case of Spain (an electric island ). Besides, hydro plants operate in combination with other non-dispatchable technologies within the system. Therefore, we also take their hourly seasonality into account. Next we run a Monte Carlo simulation to derive the risk profile of several adequacy metrics in the coming decades. Our results show that flexible hydro generation certainly mitigates the risk but is insufficient to bring an adecuate level of SoS when the enhanced renewable capacity goes hand in hand with a decreased baseload capacity. The risk further decreases after accounting for seasonal non-dispatchable generation, yet it still looms large. These results can be important for policy makers, system operators, and power companies when analizing investments in renewable energy with a long lifespan. © 2020 Elsevier LtdThis research is supported by the Basque Government through the BERC 2018–2021 program and by the Spanish Ministry of Economy and Competitiveness MINECO through BC3 María de Maeztu excellence accreditation MDM-2017-0714. Additionally, Luis M a Abadie and José M. Chamorro are grateful for financial support from the Spanish Ministry of Science and Innovation ( ECO2015-68023 ) and the University of the Basque Country - UPV/EHU ( GUI18/136

New High-Performance Materials: Bio-Based, Eco-Friendly Polyimides

The development of high-performance bio-based polyimides (PIs) seems a difficult task due to the incompatibility between petrochemical-derived, aromatic monomers and renewable, natural resources. Moreover, their production usually implies less eco-friendly experimental conditions, especially in terms of solvents and thermal conditions. In this chapter, we touch some of the most significant research endeavors that were devoted in the last decade to engineering naturally derived PI building blocks based on nontoxic, bio-renewable feedstocks. In most cases, the structural motifs of natural products are modified toward amine functionalities that are then used in classical or nonconventional methods for PI synthesis. We follow their evolution as viable alternatives to traditional starting compounds and prove they are able to generate eco-friendly PI materials that retain a combination of high-performance characteristics, or even bring some novel, enhanced features to the field. At the same time, serious progress has been made in the field of nonconventional synthetic and processing options for the development of PI-based materials. Greener experimental conditions such as ionic liquids, supercritical fluids, microwaves, and geothermal techniques represent feasible routes and reduce the negative environmental footprint of PIs’ development. We also approach some insights regarding the sustainability, degradation, and recycling of PI-based materials

New Trends in UV Curing

We present an overview of the use of photochemistry applied to polymerization and crosslinking reactions by radical or cationic process used for thin film technologies and more generally for coatings. Industrially, most of the formulations used are initiated by radical mechanism. Since the discovery by J. Crivello of iodonium and sulfonium salts, the market has been oriented to use cationic systems to crosslink monomers/ oligomers. One of the main advantage of such a system is that it is not sensitive to the presence of oxygene as it is for radical mechanisms. An overview of a photosensitive formulation is presented i.e. photoinitiators, photosensitisers, monomers and/or oligomers mainly used by formulators and additives. A new technique which has been developed to study and optimise any photosensitive formulation – differential phto calorimetry DPC – and which permits to determine kinetic parameters such as enthalpy, degree of conversion, rate constant, Arrhenius parameters, etc. is also describe. Some of the main characteristics and properties of UV cured polymers like acrylates, epoxides, vinylethers and others are correlated with their structures and the photocuring conditions. Applications to thin film technologies based on acrylates, epoxides and silicones is presented. A promising area of research which opens a new route for the obtention of new structure of alternating copolymers for coatings without the use of photoinitiator and based on charge transfer complex CTC is also presented

Dehydrochlorination of PVC Compositions During Thermal Degradation

The polyvinylchloride (PVC) differs from other polymer materials by low thermostability. The process of dehydrochlorination takes place even at low temperatures. The purpose of this investigation was to determine the influence of different PVC additives on formation of hydrogen chloride (HCl) from thermal degradation in different gaseous fluids. It has been established that the HCl formation takes place more in nitrogen as a medium than in air medium at a given temperature, especially for the high temperature region. Dibutyl phthalate (as a plasticizer) in 25 mass % w.r.t. PVC, reduces the mass loss due to HCl formation by about 5%, which is the result of two interaction processes - between HCl and plastifier degradation products. It has been found that the addition of 5 mass % of stabilizer in PVC slows down the process of dehydrochlorination and as a result the loss of mass is 2-5% less, compared to non-stabilized samples. Calcium carbonate as a filler was found to be active above 400-500 °C and reduction in mass loss was found to be up to 15% at a temperature range of 800-900 °C. Calculation of kinetic parameters shows that the rate of dehydrochlorination depends on the composition of PVC. The activation energy of formation of HCl in air, in a temperature range of 400-600 °C has been found to be 12.7, 13.3, 16.1 kJ/mol for pure, plasticized and stabilized PVC, respectively. The results reported here shall be useful for development of methods for waste utilization and their influence on the environment

Electric and Optical Properties of Polyimide Surface Films Modified by Metals

Electric and optical properties of polymer films, which were prepared on the basis of polyimides and metallized by binary aggregates Ag with Ni and Co, have been investigated. The metallized polyimide films with additional coating from Ni, Au and Rh have been studied too. It has been found that the temperature dependence of the specific surface resistance in the metallized films at the temperature from 25 up to 160 °C was in the well agreement with linear law. The specific surface resistance at 20 °C and temperature coefficient showed low values and was 0.16-2.24 Ω and 0.69×10-4-19.18×10-4 K-1 respectively. The film reflection coefficient in visible spectrum field at wavelength of 530 nm was 75% and essentially enlarged with wavelength increasing

Synthesis and Properties of Peroxy Oligomers Obtained by Telomerization Effects of the Presence of Bases

New bifunctional oligomers bearing peroxy groups have been synthesized by telomerization in one step reaction. For obtaining oligoperoxides (PO) by telomerization method, epoxide compounds will react with substances containing labile hydrogen atom. Using the principle of stochiometric imbalance between diepoxy compounds and substances with mobile hydrogen atoms and employing a functional peroxide as telogen, the synthesis of PO was studied. 2,2–Di[4–(2,3–epoxy–1-propoxy)phenyl]–propane (diglycidyl ether of diphenylol propane - DGEDPP), 1,2–Di (2,3–epoxy–1-propoxy) ethane (diglycidyl ether of ethylene glycol -DGEEG) and 1,2–Epoxy–3–tert–butylperoxypropane (EP) have been synthesized by methods reported in the literature. Chemical structures have been confirmed by NMR and FTIR, number-average molecular weights Mn of POs by cryoscopy, active oxygen content [O]act. for POs was determined by iodometry and epoxy number (e.n.) for POs was measured via direct titration of PO samples. A 50% solution of potassium or sodium isopropylates in 2-propanol is used to catalyze the telomerisation. Different parameters such as ratio of components, temperature, reaction time have been optimized in vu to get well defined peroxy oligomers. The presence of peroxy groups in synthesized POs allows us to employ these compounds as curing agents for polymers containing unsaturated double bonds and may be used to improve performance of unsaturated polyester GFR systems

Subconjunctival Injection of XG-102, a c-Jun N-Terminal Kinase Inhibitor Peptide, in the Treatment of Endotoxin-Induced Uveitis in Rats.

Abstract Purpose: XG-102, a TAT-coupled dextrogyre peptide inhibiting the c-Jun N-terminal kinase, was shown efficient in the treatment of experimental uveitis. Preclinical studies are now performed to determine optimal XG-102 dose and route of administration in endotoxin-induced uveitis (EIU) in rats with the purpose of clinical study design. METHODS: EIU was induced in Lewis rats by lipopolysaccharides (LPS) injection. XG-102 was administered at the time of LPS challenge by intravenous (IV; 3.2, 35 or 355 μg/injection), intravitreal (IVT; 0.08, 0.2 or 2.2 μg/eye), or subconjunctival (SCJ; 0.2, 1.8 or 22 μg/eye) routes. Controls received either the vehicle (saline) or dexamethasone phosphate injections. Efficacy was assessed by clinical scoring, infiltrating cells count, and expression of inflammatory mediators [inducible nitric oxide synthase (iNOS), cytokine-induced neutrophil chemoattractant-1 (CINC-1)]. The effect of XG-102 on phosphorylation of c-Jun was evaluated by Western blot. RESULTS: XG-102 demonstrated a dose-dependent anti-inflammatory effect in EIU after IV and SCJ administrations. Respective doses of 35 and 1.8 μg were efficient as compared with the vehicle-injected controls, but only the highest doses, respectively 355 and 22 μg, were as efficient as dexamethasone phosphate. After IVT injections, the anti-inflammatory effect of XG-102 was clinically evaluated similar to the corticoid's effect with all the tested doses. Regardless of the administration route, the lowest efficient doses of XG-102 significantly decreased the ration of phospho c-Jun/total c-Jun, reduced cells infiltration in the treated eyes, and significantly downregulated iNOS and CINC-1 expression in the retina. CONCLUSION: These results confirm that XG-102 peptide has potential for treating intraocular inflammation. SCJ injection appears as a good compromise to provide a therapeutic effect while limiting side effects