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Access to clean and affordable modern energy is crucial to fostering social and economic development and to achieving the Sustainable Development Goals. Efficient policy frameworks and effective electrification programs are required in order to ensure that people are electrified in a sustainable manner. These programs differ from country to country depending on geographic and socioeconomic conditions. Electrification planning process must consider the geographical characteristics of the resources as well as the spatial dimension of social and economic drivers of energy demand in order to find the most optimal energy access solution. Geographical theory and Geographic Information Systems (GIS) in particular can play a significant role in electrification planning, since they are capable of managing the data needed in the decision making process and may integrate and assess all possible options. This paper focuses on considering these characteristics by applying a recently developed GIS based methodology to inform electrification planning and strategies in Ethiopia. The paper illustrates two major aspects of energy planning; 1.) how the optimal electrification mix is influenced by a range of parameters -including population density, existing and planned transmission networks and power plants, economic activities, tariffs for grid-based electricity, technology costs for mini-grid and off-grid systems, and fuel costs for consumers and 2.) how the electrification mix differs from location to location. For a certain level of energy access, ongrid connections would be optimal for the majority of the new connections in Ethiopia; grid extension constitutes the lowest cost option for approximately 93% of the newly electrified population in this modelling effort with 2030 as time horizon. However, there are some remote areas with low population density where a mini-grid (ca. 6%) or a stand-alone solution (ca. 1%) are the most economic options. Depending on local resource availability, these systems deploy varied combinations of solar, wind, hydro and diesel technologies.

Sub-Saharan Africa has been at the epicenter of an ongoing global dialogue around the issue of energy poverty. More than half of the world's population without access to modern energy services lives there. It also happens to be a sub-continent with plentiful renewable energy resource potential. Hydropower is one of them, and to a large extent it remains untapped. This study focuses on the technical assessment of small-scale hydropower (0.01-10 MW) in Sub-Saharan Africa. The underlying methodology was based on open source geospatial datasets, whose combination allowed a consistent evaluation of 712,615 km of river network spanning over 44 countries. Environmental, topological, and social constraints were included in the form of constraints in the optimization algorithm. The results are presented on a country and power pool basis.Energies 2018, 11, 3100 of 21Recent studies indicate that the decentralization (typically of a scale less than 10 MW) of energy systems can help in addressing energy poverty [9][10][11][12][13][14]. Off-grid or mini-grid systems can be a viable near-term alternative to grid extension in many parts of Sub-Saharan Africa [15]. The prospect for decentralized energy supplies are further enhanced by the continent's abundant renewable resources. Further, the local employment is developed for deployment and maintenance of local renewable electricity generating equipment [5]. A cornerstone in the movement towards renewables is hydropower [16,17]. Role of HydropowerHydropower is a technically mature and economically competitive renewable energy source that can provide significant advantages in the operations and stability of energy systems [16]. Across Africa, hydropower is responsible for 74.2% of all non-fossil fuel electricity use [18]. In 2017 the total installed hydropower capacity in Africa was 35.34 GW [16], producing approximately 131 TWh of electricity; hydropower accounts for about 21% of the total installed capacity in the continent [16,18,19]. Focusing on Sub-Saharan Africa, the installed hydropower capacity (as in 2017) was estimated at 30.4 GW [16]. Despite this, around 92% of the 300 GW potential still remains untapped [20].The opportunities for expanding hydropower are considerable and could help support electricity provision in remote African communities, especially when developed in a small, decentralized scale [21,22]. Given favorable hydrological conditions, hydropower offers a relatively low levelized cost, continuous generation without storage requirements, and the ability to operate both in isolated or interconnected (to a national grid) mode [23]. It is estimated that the installed capacity of small-scale hydropower (below 10 MW) in Sub-Saharan Africa surpasses 476 MW [24,25].According to [21,24], the small-scale hydropower resource potential in the region is estimated at 12,197 MW, with the eastern part of the continent showing the highest potential. Szabo et al. [9] consider small-scale hydro as a very suitable option for rural electrification in Africa, showing high poten...

a b s t r a c tWater and energy supply are strongly interrelated and their efficient management is crucial for a sustainable future. Water and energy systems on several Greek islands face a number of pressing issues. Water supply is problematic as regards both to the water quality and quantity. There is significant lack of water on several islands and this is mainly dealt with tanker vessels which transport vast amounts of water from the mainland. At the same time island energy systems are congested and rely predominantly on fossil fuels, despite the abundant renewable energy potential. These issues may be addressed by combining desalination and renewable energy technologies. It is essential to analyse the feasibility of this possibility. This study focuses on developing a tool capable of designing and optimally sizing desalination and renewable energy units. Several parameters regarding an island's water demand and the desalination's energy requirements are taken into account as well as input data which concern technological performance, resource availability and economic data. The tool is applied on three islands in the South Aegean Sea, Patmos (large), Lipsoi (medium) and Thirasia (small). Results of the modelling exercise show that the water selling price ranges from 1.45 V/m 3 for the large island, while the corresponding value is about 2.6 V/m 3 for the small island, figures significantly lower than the current water cost (7 e9 V/m 3 ).

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Roughly two billion people live in areas that regularly suffer from conflict, violence, and instability. Infrastructure development in those areas is very difficult to implement and fund. As an example, electrification systems face major challenges such as ensuring the security of the workforce or reliability of power supply. This paper presents electrification results from an explorative methodology, where the costs and risks of conflict are explicitly considered in a geo-spatial, least cost electrification model. Discount factor and risk premium adjustments are introduced per technology and location in order to examine changes in electrification outlooks in Afghanistan. Findings indicate that the cost optimal electrification mix is very sensitive to the local context; yet, certain patterns emerge. Urban populations create a strong consumer base for grid electricity, in some cases even under higher risk. For peri-urban and rural areas, electrification options are more sensitive to conflict-induced risk variation. In this paper, we identify these inflection points, quantify key decision parameters, and present policy recommendations for universal electrification of Afghanistan by 2030.

The authors wish to make a change in author names (adding new author—Dimitrios Mentis) to this paper [...]

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