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Lack of access to modern forms of energy hampers efforts to reduce poverty. The provision of electricity to off-grid communities is therefore a long-standing developmental goal. Yet, many off-grid electrification projects neglect mid- and long-term operation and maintenance costs. When this is the case, electricity services are unlikely to be affordable to the communities that are the project's primary target. Here we show that, compared with diesel-powered electricity generation systems, solar photovoltaic systems are more affordable to no less than 36% of the unelectrified populations in East Asia, South Asia, and sub-Saharan Africa. We do so by developing geo-referenced estimates of affordability at a high level of resolution (1 km2). The analysis illustrates the differences in affordability that may be found at the subnational level, which underscores that electrification investments should be informed by subnational data.

Although teaching mathematics is complicated due to a wide range of crises stemming from its complex nature, the beliefs about mathematical ability and skills, the use of ICT tools in problem solving and socio-economic disruptions, current approaches focus on how to use problem solving activities such as experimenting, questioning and working collaboratively in order to build methods to increase students' facility in comprehending and learning mathematics. In this paper, we conjecture that significant improvements in teaching mathematics can be obtained by addressing the challenge of proposing a resilient strategy that involves activities based on the concepts of proximity. Since mathematical notions must be semantically close to each other, regulation, for mathematical rules and principles should be presented clearly and explicitly, and, governance of the teaching procedure is also important, meaning that the teacher ought to control the information flow presented in class, independently from the subject being taught and the context (i.e., heterogeneous groups of learners). From the students' point of view, resilience can be defined as their ability to respond to learning crises, for instance, overcome low self-esteem, be self-organized and build self-efficacy, whereas, as far as the teacher is concerned, resilience can be defined as his/her capacity to be transformed in different contexts, like interactive material, alternative teaching methods and multi-faceted skills in crisis management.

The optimization of dam operations to transform them into multi-objective facilities constitutes a challenge for both hydrology, hydrogeology, and hydropower generation. However, the use of the optimal algorithm for such transformation is critically important. Additionally, the literature has highlighted that dams might negatively influence the recharge of groundwater. Within this study, we provide an overview of the available algorithms for the optimization of dam operations. Additionally, an overview focusing on hydropower generation in Greece illustrates the high potential of the Mediterranean region for hydropower generation and the application of MAR. The water quality of the reservoirs is also highlighted as a critical parameter. Within this study, we present indices for water quality monitoring in dam reservoirs, while the most prevailing index is the SRDD. This study constitutes a guide for researchers in choosing the optimal tools for the optimization of dam operations and the water quality monitoring of reservoirs. The present study suggests a meta-heuristic optimization methodology using the harmony search algorithm. The model uses a geometric model of the reservoir and calculates the level–supply curve. Furthermore, a multi-criteria optimization model was developed with two objective functions: the maximum power output from the hydroelectric power plant turbines and the optimal groundwater recharge. The model with appropriate parameter modifications can be applied to any small dam as it is a decision- and policy-making methodology, independent of local conditions. A further step is the application of these approaches dealing with field data and the numerical modeling of case studies. The interdisciplinary approach of this study links deferent aspect and scientific perceptions, providing a comprehensive guide to optimal water resource management and environmental sustainability. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this paper is to explore and present a higher education initiative towards the training and development of Eastern European citizens, who migrate to Greece, in pursuit of bettering their economic conditions and, simultaneously, become evolving social entities, adaptable to heterogeneous environments. Design/methodology/approach: Motivated by the motto "education for all", the initiative is based on data drawn from local and public authorities and interviews that were carried out with immigrants, mainly from Albania and Ukraine. Findings: This paper proposes a learning policy and training mechanism for foreigners and the establishment of a Mediator Office providing educational services. Research limitations/implications: Further efforts are necessary to improve the teaching content in order to be in full conformity with the characteristics and requirements of non-native learners. Practical implications: Some of the constraints hampering the implementation of this initiative are the lack of the necessary financial resources, the absence of legal framework, as well as the shortage of bilingual adult training and education instructors. Originality/value: There have been limited autonomous educational programmes concerning immigrants' lifelong learning provided by the Greek Ministry of Education, focused mainly on the Greek language and history learning. This work introduces a novel educational structure, which may be established in any higher education institution and which will involve anyone in any kind of subject, anytime and anywhere.

Ordinary differential equations (ODEs) is a subject with a wide range of applications and the need of introducing it to students often arises in the last year of high school, as well as in the early stages of tertiary education. The usual methods of solving second-order ODEs with constant coefficients, among others, rely upon the use of complex variable analysis, a topic to which the students in question may not have been previously introduced. The purpose of this article is to present an alternative approach in establishing the general solution for such types of equations without using complex numbers.

In systems science, entropy is considered as the unintended process that occurs when a system fails and it is measured by change in outputs over time. In the same field, the opposite notion is homeostasis, referring to a system's ability to maintain its internal structural and functional balances. The paradox is the synergy between system maintenance and evolution. The purpose of this article is to explore the key point, during the theoretical transition of a system from the inevitable phase of entropy to the inherent phase of homeostasis, named entropoiesis, meaning the dynamic process by which a system maintains its working conditions, despite disturbances from external forces, by creating entropy to any of its components or to another system. [ABSTRACT FROM AUTHOR]

Defining flood-prone areas is particularly important for policy makers, in order to design mitigation strategies and implement flood risk management planning. The present research applies a multicriteria index method to assess flood hazard areas at a river basin scale, in a geographic information system (GIS) environment. The developed methodology has been applied for an area in northeastern Greece, by processing information of seven parameters: flow accumulation, distance from the drainage network, elevation, land use, rainfall intensity and geology. The method assigns a relative importance to each of the parameters for the occurrence and magnitude of flooding, and the relevant weight values are defined through an "analytical hierarchy process". Subsequently, and according to the relative importance of each index, the spatial information is superimposed, resulting in a flood hazard map of the studied region, an area in northern Greece. The obtained results indicate flood-prone zones, with a very high flood hazard mainly occurring at the lowlands in the vicinity of the drainage network. The provided flood hazard map supports planning activities and mitigation plans that are crucial to protect both the agricultural activities and existing infrastructure from future flood events. [ABSTRACT FROM AUTHOR]

Pumped hydroelectric storage (PHS) is the main utility-scale storage technology. Although PHS systems generally constitute a fraction of generation, they receive increasing attention due to their potential balancing role towards higher penetration of variable renewable energy sources (RES). In the European context it is widely believed that PHS are key elements of the ongoing energy transition. The present analysis examines if this assumption is valid and PHS utilization grows parallel to RES. We collected, harmonised and analysed datasets for 1991–2016 revealing an uneven utilization among European states. While certain countries increased the utilization rates of PHS by a factor of three to four, in several others PHS units are heavily under-utilized. In three extreme cases the utilization rate, compared to the past, is at 10–25% level. We analysed this controversy by identifying tendencies in the electricity markets, ownership and management status in the various countries, as well as competition with other technologies with balancing potential. Finally, we developed a new approach to display PHS tendencies in a compact picture. Building on the growth-share matrix Economics framework, we identified the strategic direction of PHS for each of the analysed countries. [ABSTRACT FROM AUTHOR]

Supplying power to remote areas may be a challenge, even for those communities already connected to the main grid. Power is often transmitted from long distances, under adverse weather conditions, and with aged equipment. As a rule, modernizing grid infrastructure in such areas to make it more resilient faces certain financial limitations. Local distribution may face stability issues and disruptions through the year and--equally important--it cannot absorb significant amounts of locally-produced power. The European policy has underlined the importance of energy production in local level towards meeting energy security and climate targets. However, the current status of these areas makes the utilization of the local potential prohibitive. This study builds on the observation that in the vicinity of such mountainous areas, irrigation dams often cover different non energy-related needs (e.g., irrigation, drinking water). Transforming these dams to small-scale hydropower (SHP) facilities can have a twofold effect: it can enhance the local energy portfolio with a renewable energy source that can be regulated and managed. Moreover, hydropower can provide additional flexibility to the local system and through reservoir operation to allow the connection of additional solar photovoltaic capacities. The developed methodological approach was tested in remote communities of mountainous Greece, where an earth-fill dam provides irrigation water. The results show a significant increase of renewables' penetration and enhanced communities' electricity autarky. [ABSTRACT FROM AUTHOR]

Recognizing the issues of land shortage and growing concerns for protecting natural lands, installers and project developers, with the help of scientists and engineers, continuously try to locate alternative spots for photovoltaic (PV) system installations. In the present paper a novel approach is suggested and analysed: installing solar PV systems on the downstream face of existing dams. This approach provides advantages that could favour even large-scale systems with a capacity of several MWp. First, produced energy could cover water reservoirs' needs supporting energy-intensive processes as water pumping and treatment in a sustainable manner. Moreover, energy provision to inhabited areas near the dams and the subsequent creation of independent mini grids could mitigate energy poverty. In the case of hydroelectric dams, the so-created hybrid system (PV-hydro) could become notably efficient, because the intermittent solar energy would be counterbalanced by the flexibility of hydropower. Finally, we found a notable number of existing water reservoirs in Africa that are either under-utilized or non-powered. That unexploited energy potential can also be amplified by PV-system installation. The analysis included data collection from various sources. Datasets have been cross-checked and extended in the newly created GIS-based model, enabling the selection of the most suitable sites in South Africa, taken as case studies. Following their identification, the selected dams have been analysed using the PVGIS tool in order to estimate the annual energy production. The results have been very encouraging, indicating that PV systems on the face of dams are an advantageous option for renewable energy production. © 2015 The Authors. Progress in Photovoltaics: Research and Applications published by John Wiley & Sons Ltd. [ABSTRACT FROM AUTHOR]

The study presents a cost effective electricity generation portfolio for six island states for a 20-year period (2015-2035). The underlying concept investigates whether adding sizeable power capacities of renewable energy sources (RES) options could decrease the overall costs and contribute to a more sustainable, indigenous electricity generation at the same time. Often, island states rely on fossil fuels which, apart from dependence on foreign resources, also includes an additional, significant transport cost. This is an extra motive to study the extent in which island states represent primary locations for RES technologies. For the aims of the present study an optimization model has been developed and following numerous runs the obtained results show that installing PV and battery capacities can delay-reduce the huge investments in fossil options in early periods. Thus, investment on RES can have a positive, long-term effect on the overall energy mix. This prompt development can happen without adding new subsidies but there is a need to address the existing socio-economic barriers with intelligent design of financing and economic instruments and capacity building as discussed in the conclusions. [ABSTRACT FROM AUTHOR]

The use of coal for electricity generation is the main emitter of Greenhous Gas Emissions worldwide. According to the International Energy Agency, these emissions have to be reduced by more than 70% by 2040 to stay on track for the 1.5–2 °C scenario suggested by the Paris Agreement. To ensure a socially fair transition towards the phase-out of coal, the European Commission introduced the Coal Regions in Transition initiative in late 2017. The present paper analyses to what extent the use of photovoltaic electricity generation systems can help with this transition in the coal regions of the European Union (EU). A spatially explicit methodology was developed to assess the solar photovoltaic (PV) potential in selected regions where open-cast coal mines are planned to cease operation in the near future. Different types of solar PV systems were considered including ground-mounted systems developed either on mining land or its surroundings. Furthermore, the installation of rooftop solar PV systems on the existing building stock was also analysed. The obtained results show that the available area in those regions is abundant and that solar PV systems could fully substitute the current electricity generation of coal-fired power plants in the analysed regions. [ABSTRACT FROM AUTHOR]

Energy planning in rural areas and in developing countries most often relies on the outputs of specialized analytical tools, of which only a handful have been developed. Over the years these tools have been upgraded, and the newest among them take into consideration, to a greater or lesser extent, all key determinants of energy generation and distribution. This article focuses on a "pool" of web‐based geo‐referencing open‐source tools and highlights the extent to which each analytical tool reflects the particularities of the various determinants of energy generation and distribution. In doing so, the present work identifies aspects of the tools that need to be strengthened. Building on this information, the article further maps the suitability of each tool with regard to calculating (at a local level) the six Sustainable Development Goal indicators that are closely related to energy. This makes it possible to draw conclusions about monitoring needs in study‐areas. Bringing together these two sets of findings, the article concludes with a research agenda for analytical tool development in the area of energy planning, which spills over developmental agendas. This article is categorized under: Energy and Development > Systems and InfrastructureEnergy and Development > Economics and Policy Electrification planning in rural areas and in developing countries most often relies on the outputs of specialised analytical tools that support geographically‐referenced analyses. The study reviews the handful of existing tools, to explore the extent to which the outputs of these tools can help to establish calculate energy‐ and climate‐related indicators that are relevant to assess the implementation of United Nations' Sustainable Development Goals. The results highlight gaps in knowledge, monitoring needs and trends across existing tools [ABSTRACT FROM AUTHOR]

The cover image is based on the Overview Next generation interactive tool as a backbone for universal access to electricity by Magda Moner‐Girona et al., DOI: 10.1002/wene.305. © EU, by Grégoire Dubois. The cover image is based on the Overview Next generation interactive tool as a backbone for universal access to electricity by Magda Moner‐Girona et al., DOI: 10.1002/wene.305. © EU, by Grégoire Dubois. [ABSTRACT FROM AUTHOR]