• Energy Research
• Open Source close
• Embargo close
• other engineering and technologies close
• ES close

[EN] The objective of this article is to compare the behaviour of the most representative domestic hot water systems (DHW) in single-family buildings. The study evaluates the energy consumption, equivalent CO2 emissions and cost for each system over a 15-year life period. This analysis is carried out in four cli- matic zones across Europe to observe the influence of climatic conditions on the results. The four climatic zones are located in the cities of Athens, Madrid, London and Berlin. The analysed systems are: a) natural gas-fired instantaneous water heaters, b) electric storage water heater, c) solar thermal system with gas- fired instantaneous, d) solar thermal system with electric storage water heater, e) air-source heat pump, f) photovoltaic system with electric storage water heater, and g) photovoltaic system with air-source heat pump. This range of technologies covers the most likely solutions to be implemented across domestic buildings in Europe.The heat pump system (HPWH) with PV considering self-consumption shows the lowest environmen- tal impact in all zones, but is not an attractive investment in the coldest zones due to lower natural gas prices. Thermal solar systems have a high purchase and maintenance costs which do not compensate their energy savings. The PV HPWH system has a greater reduction of emissions and a lower cost than HPWH across a 15-year life. The gas boiler system has the lowest cost in a 15-year period in the coldest areas, despite having a greater environmental impact than the heat pump.(c) 2023 Elsevier B.V. All rights reserved.

Abstract The study presents recent developments in the Turkish power market and introduces an Analytic Hierarchy Process model to evaluate and compare the relative overall attractiveness of power plant options for Turkey. The developed model incorporates technical characteristics, resource availability, socio-economic, environmental, cost, political, legal and organisational aspects, for evaluating and prioritising power plant types (biomass, coal, geothermal, hydro, natural gas, nuclear, petroleum, solar and wind). The study incorporates perspectives of different experts that represent various stakeholders of the Turkish power sector. The study reveals that supply reliability, investment costs and contribution to national economy are perceived as most important factors, whereas waste disposal and decommissioning costs are perceived as least important factors. Considering the overall weights, the most attractive power plant types for the Turkish power market are coal, hydro and natural gas power plants. The study indicates that Turkey should drastically decrease the installed capacity share of traditionally dominant power plants (to 58% from 89% in 2016) and fossil fuel power plants (to 40% from 56% in 2016), and increase the share of renewable power plants (to 52% from 44% in 2016), indigenous resource based power plants (to 67% from 56% in 2016) and nuclear power plants.

Cement-based materials are widely used for stabilizing and conditioning radioactive waste in low- and intermediate-level repositories. In this study, the adequacy of four different types of mortars, obtained from four different commercial cements, CEM I, II and IV (A and B), to act as barrier to 137Cs migration was analysed. Diffusion experiments using the in-diffusion (ID) method with constant tracer concentration in the reservoirs were carried out, at increasing experimental times (150, 380 and 1500 days approximately). In the experiments of less duration, and especially in CEM II and CEM I, two different pathways for diffusion were identified (fast and slow), leading to a double porosity system. However, the ???fast??? contribution to Cs diffusion, in all cases, could be neglected at larger experimental time, indicating a rearrangement of the pore structure that becomes more tight and homogeneous over time. Thus, if the experiments last enough time, only one diffusion coefficient properly describe Cs transport in these systems. Apparent diffusion coefficients, Da, obtained for Cs, range between 6.0??10???13 and 1.0??10???14 m2/s. Mortars produced with CEM IV (A and B) are the most efficient barrier for cesium transport, amongst those analysed in this study. Mortars with CEM II, which contain blast furnace slag, present the highest diffusion coefficient.

Abstract This study aims at analyzing the performance results of the European policies in energy investment within an integrated multidimensional quality measurement approach. For this purpose, the quality function deployment is adopted to the multidimensional performance measurement based on the balanced scorecard method. The dimensions and criteria of customer and technical requirements, process design, and performance measurement are defined to measure each process of QFD (Quality Function Deployment) for the energy investment policies with the supported literature. Within this context, the customer and technical requirements for energy investment policies are evaluated by considering the fuzzy decision matrix in the first process of the QFD and then, the technical requirements are used to rank the new service/product process of the energy investments in the second process of QFD. The balanced scorecard perspectives and the key factors are defined to rank the European energy investment policies respectively. Accordingly, the possible priorities of the European energy investment policies are discussed to conduct the most remarkable and efficient energy operations and the relevant results to contribute the improvement of energy sector are highlighted.

The increasing proportion of renewable energy introduces both long-term and short-term uncertainty to power systems, which restricts the implementation of energy management systems (EMSs) with high dependency on accurate prediction techniques. A hierarchical online EMS (HEMS) is proposed in this paper to economically operate the Hybrid hydrogen–electricity Storage System (HSS) in a residential microgrid (RMG). The HEMS dispatches an electrolyzer-fuel cell-based hydrogen energy storage (ES) unit for seasonal energy shifting and an on-site battery stack for daily energy allocation against the uncertainty from the renewable energy source (RES) and demand side. The online decision-making of the proposed HEMS is realized through two parallel fuzzy logic (FL)-based controllers which are decoupled by different operating frequencies. An original local energy estimation model (LEEM) is specifically designed for the decision process of FL controllers to comprehensively evaluate the system status and quantify the electricity price expectation for the HEMS. The proposed HEMS is independent of RES prediction or load forecasting, and gives the optimal operation for HSS in separated resolutions: the hydrogen ES unit is dispatched hourly and the battery is operated every minute. The performance of the proposed method is verified by numerical experiments fed by real-world datasets. The superiority of the HEMS in expense-saving manner is validated through comparison with PSO-based day-ahead optimization methods, fuzzy logic EMS, and rule-based online EMS.

Abstract Lithium-ion batteries play an important role in the life quality of modern society as the dominant technology for use in portable electronic devices such as mobile phones, tablets and laptops. Beyond this application lithium-ion batteries are the preferred option for the emerging electric vehicle sector, while still underexploited in power supply systems, especially in combination with photovoltaics and wind power. As a technological component, lithium-ion batteries present huge global potential towards energy sustainability and substantial reductions in carbon emissions. A detailed review is presented herein on the state of the art and future perspectives of Li-ion batteries with emphasis on this potential.

In contemporary electrical networks, reliability stands as a paramount attribute. Since the introduction of distributed generation (DG) and microgrid (MG) concepts has considerably changed the structure of distribution networks, it is necessary to consider reliability aspects while going toward modern smart grids. This study introduces a novel methodology focusing on the partitioning of radial distribution systems into distinct MGs, strategically aimed at minimizing energy not supplied (ENS) to fortify overall system reliability. Two types of faults are considered including DG and busbar failures, and the impact of each kind of fault is investigated. Besides, a new Markov model is proposed to evaluate the reliability of DGs and MGs. Given the stochastic nature of the majority of DGs, the incorporation of energy storage systems (ESSs) can significantly enhance system performance. Therefore, this paper dedicates attention to exploring optimal ESS placement. To address the complex challenge of optimizing system partitioning, a modified version of the group search optimization (GSO) algorithm, named dominated GSO (DGSO) is proposed. The PG&E 69-bus distribution system is studied with two different structures to accurately investigate the effectiveness of the proposed partitioning approach on the system reliability. Moreover, the optimal number of MGs to be constructed within the intended system is determined.