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Abstract Reaching universal access to electricity by 2030 requires a massive deployment of mini-grids in rural areas of developing countries. Among the many challenges hindering this process, there are the high uncertainties in assessing demand patterns in rural communities, the costs of field survey campaigns, and the absence of ample and reliable datasets coming from existing projects. This paper tries to address these issues by presenting and discussing a database of load profiles from sixty-one off-grid mini-grids from developing countries worldwide, gathered from the literature, private developers and fieldworks, and reported with technical, socio-economic and geographical characterization factors. A clustering procedure led to the identification of five archetypal load profile clusters, which are presented and analyzed together with their load duration curves. Subsequently, the distribution among the clusters of the various characterization factors selected is studied. The proposed approach allows to widen the range of load profiles usually considered, and to seek correlations between the load profile shapes, the peak power and average energy consumption per connection, the number of customers, the age of measurement, geographical position, operator model, type of tariff and generation technologies present. This work establishes a first step in the creation of a shared database for load profiles of rural mini-grids, helping to overcome the lack of available data and difficulties of demand assessment, proposing original insights for researchers to understand load patterns, and contributing to reduce risks and uncertainties for mini-grid developers.

Abstract The primary goal of the project is to design a lighting system that provides the highest visual comfort and conserves energy for different uses and furniture layouts, which considers that the design of the house will be used by many different users. Indoor system designs vary in layout, goals and optics with two levels of intervention: when initially furnished and during daily use. Lighting is managed by a building automation system, which is equipped with motion and daylight sensors and human interfaces with user scenarios. An outdoor design that requires only a standalone system and is powered by photovoltaic and eolic devices has been developed. All systems incorporate LED technology and have been custom-developed for Med in Italy, which resulted in new patents. Lighting system projects have been involved in several competitions, e.g., Med in Italy placed in the Solar Decathlon in Architecture, Electrical Energy Balance, House Functioning, and Sustainability and took third place in the final ranking. Further research developments are in progress and will be seen in next Solar Decathlon Europe in Paris in 2014. This paper describes the project, installation and analyses of the energy savings that the Medinitaly system can achieve compared with traditional solutions. Simulation data are compared with measured data from the period of the Solar Decathlon competition.

Abstract A novel integrated energy system based on a geothermal heat source and a liquefied natural gas heat sink is proposed in this study for providing heating, cooling, electricity power, and drinking water simultaneously. The arrangement is a cascade incorporating a flash-binary geothermal system, a regenerative organic Rankine cycle, a simple organic Rankine cycle, a vapor compression refrigeration cycle, a regasification unit, and a reverse osmosis desalination system. Energy, exergy, and exergoeconomic methods are employed to analyze the suggested system. A parametric study based on decision variables is carried out to better assess the system performance. Four different multi-objective optimization problems are also carried out. At the most excellent trade-off solution specified by the TOPSIS method, the system attains 29.15% exergy efficiency and 1.512 $/GJ total product cost per exergy unit. The main output products are consequently calculated to be 101.07 kg/s cooling water, 570.44 kW net output power, and 81.57 kg/s potable water.

The average antimony concentration in municipal solid waste is estimated to be about 10-60 ppm. Thermodynamical models predict a volatile behavior for antimony compounds, yet literature mass balances show that about 50% of the antimony input remains in the grate ashes. This fact can be explained by the formation of thermally stable antimonates in the fuel bed due to interactions with alkali or earth-alkali metals. Thermogravimetric experiments revealed an increased thermal stability for antimony oxide in presence of oxygen and calcium oxide. Spiking experiments on the test incinerator TAMARA showed that chlorination processes have a strong effect on antimony volatilization whereas high fuel-bed temperatures and addition of antimony oxide only have a moderate effect. In the grate ashes, antimony shows a pH-depending leaching property, which is typical for anionic species. This fact supports the thesis that antimony is present in the grate ashes in an anionic speciation.

Abstract This paper investigates two transition initiatives at the local level – namely the reconversion of the Porto Marghera and Gela refineries into biorefineries for second-generation biofuels. The study aimed at assessing the extent to which the narrative pressures exerted by local actors influenced the perspectives of key stakeholders involved in these transition processes. To this end, a blended methodology was employed, combining discourse analysis with stakeholder analysis and semi-structured interviews. First, stakeholders were grouped into four categories according to the source (national/global) and channel (formal/informal) of pressure. National/informal actors emerged as the most influential group. The discourse analysis identified three dominant storylines representing complementary trajectories defined by national actors operating through informal channels. Finally, semi-structured interviews with key local actors involved in the Porto Marghera and Gela reconversions were used to assess the impact of these storylines in the reconversion processes. Comparison of the two cases revealed fundamental specificities related to their respective cultural, political and socio-economic contexts. While the Porto Marghera reconversion was presented as a consolidated success story (albeit with a number of drawbacks related to the fact that it was still mainly powered by first-generation feedstocks), the Gela case was viewed as a complex and challenging ongoing process with an uncertain outcome.

The rapid increase of electric vehicles (EVs) penetration represents an important challenge for the distribution system operator (DSO). The main issues arise not only from an optimal grid expansion planning point of view but also for managing the system in the near future. The paper focuses on a short-term period EV penetration scenario and proposes a mechanism of EV charging sessions rescheduling in order to mitigate grid congestions. The collaboration between three actors, namely the DSO, the fleet manager and the end user, allows the DSO to identify rescheduling programs in order to face overload events, that represent the most important issue for the grid caused by the widespread penetration of EVs. The IEEE 33-bus test system is used to check the potential of the proposed mechanism. Load flow simulations show that more than 50% of congestions are avoided by means of this approach. The promising results constitute a base case for a future work in which the optimal rescheduling program would be investigated.

Abstract This computational work was conducted to describe the atomic behavior of Ar atoms in the presence of Cu, Fe, and Cu/Fe nanoparticles via the molecular dynamics (MD) approach. The results of our simulations on the atomic behavior of various structures were reported by calculating physical quantities, such as temperature, total energy, aggregation time, and density/velocity/temperature profile. Computational results revealed that the total energy, the solar energy for instance, converged to a negative value after t = 5 ns. This calculation estimates the atomic stability of nanostructures. Numerically, by adding Cu/Fe nanoparticles to Ar base fluid, the aggregation time in atomic structures increased to 4.59 ns; this atomic improvement could be used for heat/mass transfer aims.

A family of mixed vanadium oxides LiCoyNi(1−y)VO4 (x=0.2, 0.5 and 0.8) of potential use as high voltage cathode materials in lithium batteries, has been synthesized and characterized. In general the x-ray diffraction analysis showed that these compounds have an inverse spinel structure where about 85 % of the Ni2+ and Co2+ ions occupies octahedral sites and the rest tetrahedral sites along with the V5+ ions. Moreover, the annealing temperature plays a key role in determining the particle size, as demonstrated by scanning electron microscope analysis. Cycling voltammetry tests showed that the lithium insertion-extraction process in the LiCoyNi(1−y)VO4 electrode materials occurs reversibly at around 4.3–4.4 V vs. Li and these results are confirmed by cycling tests.

Abstract Polygeneration of electric power, cooling and fresh water from seawater and brackish water by using solar energy is discussed in this paper. The best plant component arrangement has been selected for a 400–600 square meter Solar Dish surface. The engine is made of turbomachinery derived from the Internal Combustion Engine Turbocharger Technology for reliability and economy reasons. The Micro Gas Turbine has been selected taking the ©GICE complex arrangement concept into account. Such an arrangement is capable of concurrent production of power and of a cold stream by the expansion in the Power Turbine. Such a cold stream is used for ©CryoDesalination of seawater and cooling. An example has been presented, it demonstrates the potential of large solar dish technology used to feed solar energy in an integrated system made of a ©GICE engine, ©CryoDesalination group and a collector of the cold streams for cooling purposes. Two options have been explored and compared.