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The global energy demand is growing substantially. Clean and secure energy supply is a must for our civilization's sustainable development.Solar and wind energy is growing fast and can contribute significantly to meet the goals set by many countries to reduce greenhouse gas emissions. A deep and wide investigation of the environmental impact of solar and wind energy is important before any solar or wind plants' construction is made. In this study, the literature is reviewed to summarize theenvironmental impact of solar and wind energy systems in terms of the following factors; land use, water consumption, impact on biodiversity, visual and noise effects, health issues, and impact on micro climate. Although the benefits of solar and wind energy are obvious and great, negative perception of these technologies can inhibit their wide penetration in some regions. This review paper includes a critical and an inclusive analysis of solar and wind energy’s environmental impact and may serve as an important tool to conduct a proper environmental impact assessment. This critical analysis may serve also as a tool for developers, policy, and decision-when planning future solar and wind farms.&nbsp

Energy poverty is the inability of people to have an adequate access to energy sources. It is complex and multi-dimensional problem. This paper examines both the prospects and constraints that exist in the integration of renewable energy systems that would aid in reducing poverty and promote sustainability in Palestine. Both energy and fuel poverty plague Palestine because of the many inadequate grid systems and a lack of electricity access that barely meets household standards. Palestine's complete reliance on fuel and electricity has perpetuated multiple challenges for its energy sector. The Palestinian energy supply faces considerable challenges that are due to its full reliance on Israel for 100% of its fossil fuel imports and for 90% of its electricity supply. This dependency has caused the energy sector to face political, cultural and socio-economic challenges, which then results in the sector being chronically vulnerability to political and economic change. The instability in Palestine prevents full utilization and development of renewable energy that has the potential to alleviate energy poverty. Many low-income families struggle with securing energy needs due to these hindrances along with inadequate heating/cooling, housing and increases in energy costs. This study suggests some recommendations which when considered would help reduce energy poverty in Palestine. The presented results show that poverty and energy poverty in Palestine go hand in hand. Focusing on country’s policy instruments is crucial to reduce the barriers towards the use of renewables and is the golden thread that will wave together economic growth, development and environmental sustainability.

The usage of renewable energy sources increases the energy security because it brings extensive socio-economic benefits to Israeli and Jordanian populations, added pathways for bilateral cooperation and allows countries to achieve their climate mitigation goals. Israel and Jordan's energy mix are both dominated by fossil fuel usage and produce only 4% of their energy supply from renewable energy. Each have been affected by the events of the Arab Spring and the discovery of the Tamar and Leviathan natural gas fields. Both countries are vulnerable to political instability and climate change. Although Israel and Jordan have set targets to attain 10% renewable energy by 2020 the progress is slow and both countries may not reach this goal if the implementation occurs at the current pace. Current policies include feed-in tariffs and auctions for renewable projects. Both would benefit from increased investment electric in vehicles, better connectivity to the grid and greater cross-border cooperation.

The efficiency of photovoltaic modules depends mainly on the cell operating temperatures. Performance enhancement of building-integrated photovoltaic (BIPV) panels by passive cooling has been investigated both experimentally and with computational modeling. It has been shown that mounting the BIPV with a narrow channel can reduce the operating temperature of the photovoltaic panel. This enhancement in the heat transfer from the PV panel results in decreasing the average temperature of the PV panel from 5 to 10 °C. Results show that having a 30 cm channel beneath the panel can increase the electrical output by 3–4%. This increase in PV output can translate into a significant amount over the life cycle of a given PV module. Various channel aspect ratios have been tested in order to correlate the enhancement in performance to the cooling channel geometry. There is significant consistency between the experimentally measured PV panel surface temperatures and those obtained from the computational model.

The world’s rural population surpasses the three billion people mainly located in Africa and Asia; roughly half the global population lives in the countryside. Access to modern fuels is a challenge for rural people compared to their urban counterparts, which can easily access infrastructures and commercial energy. In developing countries rural populations commonly depend on traditional biomass for cooking and heating. A key strategy in tackling the energy needs of those rural populations is to advance their energy ladder from the inefficient, traditional domestic burn of biomass, organic waste, and animal manure. Governments and non-governmental institutions have supported small biogas digesters in rural areas, mainly in Asia, South America, and Africa, over the last 50 years. This chapter reviews the literature to offer an overview of experimental and theoretical evidence regarding the characteristics of design, construction material, feedstock, and operation parameters that made anaerobic digestion in small digesters a valuable source. Small-scale rural biogas digesters can generate environmental, health, and social benefits to rural areas with a net positive impact on energy access. Remarkable improvement in living standards was achieved with small inputs of the methane, produced via anaerobic digestion; however, challenges associated with lack of technical skills, awareness, and education remain and obstruct biogas’ full potential in rural areas, mainly in developing countries.

The intensity and duration of hot weather and the number of extreme weather events, such as heatwaves, are increasing, leading to a growing need for space cooling energy demand. Together with the building stock’s low energy performance, this phenomenon may also increase households’ energy consumption. On the other hand, the low level of ownership of cooling equipment can cause low energy consumption, leading to a lack of indoor thermal comfort and several health-related problems, yet increasing the risk of energy poverty in summer. Understanding future temperature variations and the associated impacts on building cooling demand will allow mitigating future issues related to a warmer climate. In this respect, this paper analyses the effects of change in temperatures in the residential sector cooling demand in 2050 for a case study of nineteen cities across seven countries: Cyprus, Finland, Greece, Israel, Portugal, Slovakia, and Spain, by estimating cooling degree days and hours (CDD and CDH). CDD and CDH are calculated using both fixed and adaptive thermal comfort temperature thresholds for 2020 and 2050, understanding their strengths and weaknesses to assess the effects of warmer temperatures. Results suggest a noticeable average increase in CDD and CDH values, up to double, by using both thresholds for 2050, with a particular interest in northern countries where structural modifications in the building stock and occupants’ behavior should be anticipated. Furthermore, the use of the adaptive thermal comfort threshold shows that the projected temperature increases for 2050 might affect people’s capability to adapt their comfort band (i.e., indoor habitability) as temperatures would be higher than the maximum admissible values for people’s comfort and health., The paper stems from collaborative work within COST Action ‘European Energy Poverty: Agenda Co-Creation and Knowledge Innovation’ (ENGAGER 2017–2021, CA16232) funded by European Cooperation in Science and Technology—www.cost.eu (5 December 2020). João Pedro Gouveia and Pedro Palma acknowledge and are thankful for the support provided to CENSE by the Portuguese Foundation for Science and Technology (FCT) through the strategic project UIDB/04085/2020 and through the scholarship SFRH/BD/146732/2019 provided to Pedro). Ricardo Barbosa acknowledges the support for this work, which was partly financed by FCT/MCTES through national funds (PIDDAC) under the R&D Unit Institute for Sustainability and Innovation in Structural Engineering (ISISE), under reference UIDB/04029/2020.

Extreme energy poverty results from a mix of conditions including lack of access to a reliable and affordable grid-based energy source that meets basic domestic needs. In this paper, we focus on two communities that face multiple complications regarding modern energy and housing infrastructure: Roma neighborhoods in Romania and Bedouin villages in Israel. Our goal is threefold: to map within the two national contexts existing norms, policies and regulation with references to energy poverty; to identify and analyze the main characteristics and challenges associated with extreme energy poverty; finally, to highlight and discuss the nexus of infrastructure, planning and social inequality from the perspective of energy provision. Research methods included regulatory and policy analysis as well as interviews with policy and decision-makers in both countries. We found that, in both national contexts, laws and policies avoid a clear definition of energy poverty, instructions on how to measure it, and a systematic collection of relevant data. At the same time, there are no long-term policies to tackle energy poverty at a national scale. The study also found that policymakers perceive extreme energy vulnerability to be less urgent than other challenges for these excluded communities, and that long-lasting mistrust is a prominent characteristic of extreme energy conditions, as we define for the first time. Our additional contribution is conceptual: we show how informal housing conditions are combined with additional spheres of informalities, and how informal coping strategies with the challenge of energy poverty may be adopted by policymakers.

The heuristic multi-level perspective framework (MLP) is applied here to explore the innovation process and determinants of adoption and diffusion of an individual project. Drawing on insights from this explanatory and integrative framework, we benefit from an in-depth examination into drivers and barriers to biogas technology. We retrospectively investigate a frame of the project “Integrated Waste Recycling Systems for Agricultural and Environmental Safety Purposes in Rural Communities in Jordan and Israel”. Precisely, our work focuses on the outcomes of the implementation of biogas units in three Bedouin villages in Southern Israel. The adoption and diffusion of technology incorporated learning processes and changing behaviours such as skill development, competencies, social practices and new social roles. Knowledge, and financial and policymaker support were critical drivers. Besides, the involvement of women and young community members was a crucial aspect of the adoption. By contrast, patriarchy and financial capability represented barriers. We commented on the creation of social niches, and we recognised niche management actions along with the project progression. The introduction of social niches concept represents an extension to the traditional MLP vocabulary throughout a new paradigm of meanings. The social niche plays the role of the agency that embodies individuals’ level and bridges social practices to the regime. Moreover, we conclude that the biogas innovation process was the outcome of the coevolution of technological and social niches. Furthermore, we assert the importance of exploring the role of social niches and niche strategic management in the transition studies in poor contexts.

Photovoltaics is amongst the most important technologies for renewable energy sources, and plays a key role in the development of a society with a smaller environmental footprint. Key parameters for solar cells are their energy conversion efficiency, their operating lifetime, and the cost of the energy obtained from a photovoltaic system compared to other sources. The optimization of these aspects involves the exploitation of new materials and development of novel solar cell concepts and designs. Both theoretical modeling and characterization of such devices require a comprehensive view including all scales from the atomic to the macroscopic and industrial scale. The different length scales of the electronic and optical degrees of freedoms specifically lead to an intrinsic need for multiscale simulation, which is accentuated in many advanced photovoltaics concepts including nanostructured regions. Therefore, multiscale modeling has found particular interest in the photovoltaics community, as a tool to advance the field beyond its current limits. In this article, we review the field of multiscale techniques applied to photovoltaics, and we discuss opportunities and remaining challenges. © T. Abu Hamed et al., published by EDP Sciences, 2018., European Cooperation in Science and Technology: MP1406, The authors are grateful for the financial support by the COST Action MP1406 “MultiscaleSolar.”

Off-grid energy systems are the main electricity source in rural Bedouin villages in the Negev. Due to the need for electricity, Bedouin households took upon themselves the responsibility of buying and installing photovoltaic (PV) systems. This study is the first of its kind to present data on energy poverty and installed PV systems at the recognized and unrecognized Bedouin villages to assess their future electricity needs. Interviews were conducted in four Bedouin villages (Wadi El Neam, Qasr El Sir, Wadi Areha and Ber Hadaj). It was found that although Bedouin households rely heavily on the PV systems to provide them with the electricity needed in their daily lives, they use the diesel generators when the PV system are not able to produce energy. It was also found that the generated electricity from PV systems is limited and insufficient to meet basic needs and it shapes the villagers’ daily life. The Bedouin communities use minimum energy consumption associated with their basic necessities. Enlarging the current installed photovoltaic system emerged as an urgent need.

This study examines the kinetics of boron hydrolysis. The boron hydrolysis reaction is classified as a noncatalytic heterogeneous reaction. It was found the steam rapidly hydrolyzes the boron, forming an oxide ash layer that then also reacts with the steam, forms gaseous boric acid, and re-exposes the boron substrate to steam. Additionally, the thickness of the ash layer, once formed, was found to be relatively constant through the reaction. In order to facilitate kinetic analysis the reaction was divided into two stages: a fast oxidation stage and a second, slower stage. The corresponding kinetic parameter for the first stage activation energy is 25 kJ/mol. The shrinking core model was used to model the second stage of the hydrolysis reaction where it was found that diffusion of steam through the ash layer was the rate limiting step.

An electrostatic self-cleaning panel for solar collectors is described. An electrodynamic screen (EDS) is formed by interdigitated transparent surface electrodes energized by three-phase low-frequency ac voltages in the range of 5-200 Hz and 500-1000 V. The resulting electrostatic field wave exerts force on the particles and sweeps them laterally across the panel. Particle trajectories are simulated to help ascertain parameters for maximum dust-removal efficiency. The electric field of the EDS is found by a Fourier expansion of Laplace's equation solutions for a surface potential that is periodic in space and time. Trajectories are found for particles of various sizes and charges and for different electrode spacings and excitations. Computed trajectories are compared qualitatively to experimental observations. One unexpected result is the chaotic behavior of larger particles which jump sporadically back and forth and only slowly migrate in the direction of the imposed electrostatic surface wave.

Hydrolysis of boron is investigated as a part of a boron/boron oxide solar water splitting-thermochemical cycle. Boron was hydrolyzed and boron oxide was gasified with steam in a tubular reactor. The effects of the reactor temperature and water flow rate on hydrogen production and boron oxide gasification were studied at different furnace set point temperatures and water flow rates. The produced hydrogen was measured by inline gas chromatography. Results show that the hydrogen production rate increased by increasing the reaction temperature and water flow rate. The range of hydrogen production efficiency of 95–100% was obtained for all experiments, as well as a full conversion of the boron particles to boron oxide, and the boron oxide to orthoboric acid. It was observed that the hydrogen production rate was high at the beginning of the hydrolysis process and decreased gradually with time. The X-ray analysis showed that the boron was converted into boron oxide and boric acid. The formation of a boric acid layer on the reactor walls was attributed to the gasification of the boron oxide.

The cometabolic degradation of trichloroethylene (TCE) by Pseudomonas putida F1 (strain ATCC 700007) at different concentrations was studied in single- and two-phase systems using 2-undecanone as the second organic phase. Toluene vapors were used as the primary growth substrate for Pseudomonas putida F1. The effects of the biomass concentration and the phase ratio on the biodegradation process were investigated. The best biomass concentration and the most suitable phase ratio were found to be 0.462 and 0.025 g/L (vorg/vaq), respectively. In the single-phase system, 36.5 mg/L TCE was degraded completely in 15 hours and only 78% of 55 mg/L TCE was degraded in 27 hours, while in the two-phase system 55 mg/L TCE was degraded completely in 14 hours. The use of the two-phase system not only decreased the biodegradation time of TCE but also prevented the inhibition effect of high concentrations of TCE on the microbial biomass.

The Palestinian Territories relies on Israel for 100% of its fossil fuel imports and for 87% of its electricity imports. Total energy consumption in the Palestinian Territories is the lowest in the region and costs more than anywhere else in the Middle East. The purpose of this paper is to present the current energy situation in the Palestinian Territories, evaluate the potential of renewable energies in meeting part of the energy demand and discuss the challenges and benefits of using these types of energies. It is shown that the main renewable energy sources in the Palestinian Territories are solar, wind and biomass. Using the available renewable energy sources in the Palestinian Territories may significantly decrease the energy reliance on neighboring countries and improve the Palestinian population's access to energy. It is estimated that solar sources have the potential to account for 13% of electricity demand and wind energy for 6.6%. The conversion of animal waste into biogas has the potential to meet the needs of 20% of the rural population. The conversion of unused agricultural residue into biodiesel could replace 5% of the imported diesel.

Boron has been proposed as a candidate for hydrogen production. In this study a process is described in which boron is used as a means to store and transport solar energy from a production site to motor vehicles, where it is used to generate hydrogen and heat. The proposed multi-step fuel cycle includes no carbon as a reducing agent and, therefore, no release of CO 2 to the atmosphere. This process is safe, mostly involving harmless materials and well-understood technologies. It eliminates the distribution, storage, and pumping of hydrogen at the refueling station, and diminishes the amount of hydrogen stored on the vehicle to a minimum. It is shown that the boron reaction with water, performed on-board of a vehicle, has high hydrogen storage capacity based on both volume and mass, compared with other candidate technologies. An energy balance of the entire process predicts that the overall efficiency of converting solar energy to work by the vehicle engine can be about 11%.

A two-phase aqueous-organic system was used to degrade benzene, toluene and phenol, individually and as mixture by Pseudomonas putida F1 (ATCC 700007). In the first stage of the work, the effect of the phase ratio (0–1, v/v) and the agitation rate (150 and 200 rpm) on the biodegradation process was investigated in an orbital shaker using 2-undecanone as the solvent and the most suitable phase ratio and agitation rate were found to be 0.0625 (v/v) and 200 rpm, respectively. P. putida F1 was added into the aqueous phase of the two-phase system, which consisted of a 40 ml aqueous phase and 2.5 ml 2-undecanone. Experiments were carried out at pH 7 and 30 °C. Benzene, toluene and phenol individually were consumed completely below concentrations of 4400 mg l−1 benzene, 4200 mg l−1 toluene and 600 mg l−1 phenol according to the aqueous phase volume. The presence of the second phase (organic phase) not only prevented the inhibition effect of the substrates, but also decreased the biodegradation time. The maximum overall biodegradation rates of benzene, toluene and phenol were obtained as 183, 197 and 18 mg l−1 h−1, respectively. In the biodegradation experiments using mixtures, the presence of phenol did not change the biodegradation times of benzene and toluene and, the presence of benzene and toluene decreased the biodegradation times of phenol.

Hydrolysis of boron is investigated as a part of a boron/boron oxide solar, water-splitting, thermochemical cycle. Boron was hydrolysed and boron oxide was gasified with steam in a tubular reactor. The influence of the reactor temperature and time on hydrogen conversion was measured at furnace set point temperatures of 873, 973 and 1073 K. The hydrogen production rate was measured by inline gas chromatography. The products were analyzed by X-ray diffraction. The average hydrogen production efficiency of 92% was obtained for both 973 and 1073 K. The formation of a boric acid layer on the reactor walls was attributed to the gasification of the boron oxide. The X-ray analysis shows 100% conversion of the boron to boron oxide and boric acid.

The synthesis and hydrolysis of zinc nanoparticles are carried out in a tubular reactor. A key component of the reactor is a coaxial jet quench device. Three coaxial and multi-inlet confined jets mix Zn(g), steam, and argon to produce and hydrolyze zinc nanoparticles. The performance of the quench device is assessed with computational fluid dynamics modeling and measurements of hydrogen conversion and particle size and composition. Numerical data elucidate the impact of varying jet flow rates on temperature and velocity distributions within the reactor. Experiments produce hydrogen conversions of 61–79%. Particle deposition on sections of the reactor surface above 650 K favors hydrolysis. Residence time for in-flight particles is less than 1 s and these particles are partially hydrolyzed.

Hydrolysis of Zn is investigated as the second step in a ZnO∕Zn redox solar water splitting process. Zinc is evaporated and hydrolyzed with steam in a hot wall flow tubular reactor. The influence of the reactor temperature distribution and residence time on hydrogen conversion was measured for furnace set point temperatures of 1023K and 1073K. The yield of ZnO aerosol was measured in situ using a scanning differential mobility sizer. The composition and morphology of the solid product were characterized with X-ray diffraction and microscopy. Hydrogen conversions of 87–96% at temperatures above zinc saturation are attributed primarily to hydrolysis of zinc(g) at the wall of the reactor at temperatures from 800Kto1077K.

Boron hydrolysis reaction can be used for onboard production of hydrogen. Boron is a promising candidate because of its low molecular weight and relatively high valence. The oxide product from this process can be reduced and the boron can be recovered using known technologies, e.g., chemically with magnesium or via electrolysis. In both routes solar energy can play a major role. In the case of magnesium, an intermediate product, magnesium oxide, is formed, and its reduction back to magnesium can exploit solar energy. The boron hydrolysis process at moderate reactor temperature up to 650°C, potentially suitable for use in vehicles, has not been sufficiently studied so far. This paper addresses the operational requirements using an experimental setup for investigating the hydrolysis reaction of metal powders exposed to steam containing atmosphere. The output hydrogen is measured as a function of temperature in reaction zone, steam partial pressure, and the different steam to metal ratio. Test results obtained during the hydrolysis of amorphous boron powder in batch experiments (with 0.1–2g of boron, water mass flow rate of 0.1–1g∕min, carrier gas flow rate of 100cm3∕min at total atmospheric pressure with steam partial pressure of 0.55–0.95bar abs) indicate that the reaction occurs in two different stages, depending on the temperature. A slow reaction starts at about 300°C and hydrogen output increases with reactor temperature and steam partial pressure. The fast stage starts as the reactor temperature approaches 500°C. At this temperature, the reaction develops vigorously due to higher reaction rate and its strong exothermic nature. The fast stage is self-restrained when 50–60% of the loaded boron is reacted and 1.5–1.8 SPT L H2 per 1g of boron is produced. Raising the temperature before the steam flow starts during the preheating period above 500°C increases the hydrogen yield at the fast stage. Then, the reaction continues for a long time at slow rate until the hydrogen release is terminated. The duration of the fast step decreases sharply with the increase of the steam to boron ratio.

The synthesis and hydrolysis of zinc nanoparticles are carried out in a tubular reactor. A key component of the reactor is a coaxial jet quench device. Three co-axial and multi-inlet confined jets mix Zn(g), steam and argon to produce and hydrolyze zinc nanoparticles. The performance of the quench device is assessed with computational fluid dynamic modeling and measurements of hydrogen conversion and particle size and composition. Numerical data elucidate the impact of varying jet flow rates on temperature and velocity distributions within the reactor. Experiments produce hydrogen conversions of 61 to 79%. Particle deposition on sections of the reactor surface above 650 K favors hydrolysis. Residence time for in-flight particles is less than one second and these particles are partially hydrolyzed.Copyright © 2008 by ASME

Hydrolysis of Zn is investigated as the second step in a ZnO/Zn redox solar water splitting process. Zinc is evaporated and hydrolyzed in a hot wall flow tubular reactor. The design of the reactor was suggested by prior studies at ETH-Swiss Federal Institute in which simultaneous synthesis of hydrogen and zinc oxide nanoparticles was the goal. The influence of the reactor temperature and residence time on hydrogen conversion was measured for 1023 and 1073 K. Particle yield was measured in-situ using a scanning differential mobility sizer. Particle composition and morphology were characterized with X-ray diffraction and microscopy. In agreement with the prior work, hydrogen conversions of 87 to 96 percent at temperatures above zinc saturation are attributed primarily to hydrolysis of zinc(g) at the wall of the reactor.Copyright © 2007 by ASME