Off-grid Communities Research Articles

Estimating theoretical stress regime for engineered geothermal energy systems in an arctic community (Kuujjuaq, Canada)

In remote northern regions, lacking deep geothermal exploratory boreholes, a theoretical approach to provide a first-order estimate of the stress regime seems a useful tool. Literature data was used in this context to evaluate the orientation of the stress components and empirical relationships were applied to calculate their magnitude in a community of Nunavik, northern Quebec. A Monte Carlo-based sensitivity analysis was carried out due to the uncertainty of the input parameters. Mohr–Coulomb friction and slip tendency analyses were additionally undertaken to assess the stress state and potential reactivation of existing fractures. The results highlight how the poor knowledge of the stress field has an important impact on the design and development of engineered geothermal energy systems in the Canadian off-grid community of Kuujjuaq.

Analysis of a self-sufficient photovoltaic system for a remote, off-grid community

Background A photovoltaic (PV) system, especially the stand-alone type, along with a battery storage system, plays a significant role in providing the needed electrical energy to remote, off-grid communities. Methods In this study, a stand-alone PV solar cell was enhanced to better understand the system operation. Modeling and simulation were performed using MATLAB software. Results This work has shown that the I-V (current-voltage) and P-V (power-voltage) characteristics of the modelled system have a profound effect on energy when a pulse width modulation controller is used as a charger. The modelled PV system generated the required energy under different conditions, considering temperature and PV battery voltage mismatches. Conclusion In summary, the simulated model in this study can be considered a system capable of detecting different conditions with the presence or absence of light at different temperatures. Finally, monitoring the temperatures, adjusting the voltage with a suitable charger controller, and selecting solar modules made of optimal materials can increase the efficiency of the solar system and allow it to be used in more applications.

Micro Pumped Hydro Energy Storage: Sketching a Sustainable Hybrid Solution for Colombian Off-Grid Communities

Currently, electricity generation in off-grid communities is done through polluting and often inefficient diesel generators. When renewable energies are implemented, they are often coupled with chemical batteries, whose specificities do not fit well with remote and harsh environments. As a more sustainable alternative, this paper looks at micro pumped hydro energy storage coupled with solar photovoltaic production. Rural electrification in Colombia is selected as the best potential context for such a solution. Several electrical machines are considered for energy conversion (associated with one pump also utilized as turbine for robustness and cost reasons) and rated over-dedicated criteria: reactive power, efficiency, price, flexibility of power intake, complexity, and robustness. This sketching phase highlights two machines, induction and permanent magnet synchronous machines, both coupled with a variable frequency drive. Two microgrid configurations are also selected that best suit this storage technology to the needs of Colombian non-interconnected zones. A pursuit of low-tech, robust solutions is carried in this paper for reasons of costs, maintenance, and local appropriation.

Safe passage for fish: The case for in-stream turbines

Current hydro power turbine technology is reviewed regarding safe fish passage. Much of the literature has focused on dam turbine configurations, while some have recommended to develop in-stream turbines as an alternative and potentially more environmentally- and ecologically-friendly option. Throughout the literature, several key design parameters and considerations appear consistently, with which future turbines are recommended to be designed if installed near fish habitats or migratory routes. Design parameters and recommendations are compiled and examined here, and conclusions about future developments of hydro turbines are provided. Additionally, the criteria and considerations are applied to an in-stream turbine design, which is shown to exhibit fish-friendly operation over a wide range of riverine velocities with mitigated fish access to the tip region. It is shown that in-stream turbines are a future-friendly (environmentally, ecologically and socially) technology that can provide sustainable energy generation to people throughout the world as an alternative to dams, including those in off-grid communities with little-to-no access to electricity.

Advancing convergence research: Renewable energy solutions for off-grid communities

Millions of people across the world live off-grid not by choice but because they live in rural areas, have low income, and have no political clout. Delivering sustainable energy solutions to such a substantial amount of the world's population requires more than a technological fix; it requires leveraging the knowledge of underserved populations working together with a transdisciplinary team to find holistically derived solutions. Our original research has resulted in an innovative Convergence Framework integrating the fields of engineering, social sciences, and communication, and is based on working together with communities and other stakeholders to address the challenges posed by delivering clean energy solutions. In this paper, we discuss the evolution of this Framework and illustrate how this Framework is being operationalized in our on-going research project, cocreating hybrid renewable energy systems for off-grid communities in the Brazilian Amazon. The research shows how this Framework can address clean energy transitions, strengthen emerging industries at local level, and foster Global North-South scholarly collaborations. We do so by the integration of social science and engineering and by focusing on community engagement, energy justice, and governance for underserved communities. Further, this solution-driven Framework leads to the emergence of unique approaches that advance scientific knowledge, while at the same time addressing community needs.

Food production in space from CO2 using microbial electrosynthesis

The current food method in space is launching prepackaged food which is costly and unsustainable. Alternatives include growing crops and microalgae single cell protein (SCP) using artificial light photosynthesis, which are energy inefficient. Prepackaged food and microalgae food were compared to microbial electrosynthesis of acetic acid (MES-AA). Since the dominant cost of a space mission is the cost of launching mass, components of a system were converted to an equivalent mass, including power, heat rejection, and volume. Three-year roundtrip crewed missions were evaluated for the International Space Station, the Moon, and Mars. The average Equivalent System Mass (ESM) of MES-AA is 1.38x and 2.84x lower than prepackaged food and microalgae SCP, respectively. The expected electricity-to-calorie conversion efficiency of MES-AA is 19.8 %, consuming 3.45 kW to fully feed five astronauts; diets would realistically include multiple foods. MES-AA has a higher energy efficiency than any currently investigated resilient food in space. MES-AA can provide diet diversity at a lower cost than customarily storing prepackaged food or growing crops in space. Producing food while contributing to closed loop life support in space can contribute to reducing global catastrophic risk and is relevant in off-grid communities, like in rural Alaska.

Sustainable electricity supply for small off-grid communities in Colombia: A system dynamics approach

Colombia, like many other low and middle-income countries, faces an electricity access deficit. Even where access is available, many off-grid communities are only provided with a few hours of service, typically using diesel, which is expensive and polluting. Using a system dynamics model, this paper investigates how a sustainable and durable electricity supply can be provided in off-grid communities in Colombia. The scenarios examined draw on two government funds that have been established to: deliver the infrastructure and provide subsidies for electricity supply. The results demonstrate that a transition from diesel to renewables is not only possible but also economically viable and desirable. The simulations also show that in order to make the best use of limited government funding for electrification, the transition from diesel to renewables should begin as soon as possible and be accompanied by a zero-diesel policy by 2040. Furthermore, the model highlights that electricity systems should be designed to enable gradual growth in demand – driven by socio-economic development and productive uses. Given the imperative to provide a sustainable and durable electricity supply to off-grid communities, this paper provides insights into how this can be achieved while delivering clear benefits for users, utilities and the government.

Three-dimensional open architecture enabling salt-rejection solar evaporators with boosted water production efficiency

Direct solar desalination exhibits considerable potential for alleviating the global freshwater crisis. However, the prevention of salt accumulation while maintaining high water production remains an important challenge that limits its practical applications because the methods currently employed for achieving rapid salt backflow usually result in considerable heat loss. Herein, we fabricate a solar evaporator featuring vertically aligned mass transfer bridges for water transport and salt backflow. The 3D open architecture constructed using mass transfer bridges enables the evaporator to efficiently utilize the conductive heat that would otherwise be lost, significantly improving the water evaporation efficiency without compromising on salt rejection. The fabricated evaporator can treat salt water with more than 10% salinity. Moreover, it can continuously and steadily work in a real environment under natural sunlight with a practical solar-to-water collection efficiency of >40%. Using the discharged water from reverse osmosis plants and sea water from the Red Sea, the evaporator demonstrates a daily freshwater generation rate of ~5 L/m2, which is sufficient to satisfy individual drinking water requirements. With strong salt rejection, high energy efficiency, and simple scalability, the 3D evaporator has considerable promise for freshwater supply for water-stressed and off-grid communities.

Adobe bricks as zero-material-cost solar evaporators for water-scarce regions

Consistent access to clean water is amongst the most pressing of global crises, particularly in less developed and off-grid communities. We present a high-efficiency solar evaporation device perfectly suited to address this crisis. Composed solely of soil, the adobe brick is a material that is easy to fabricate, and whose raw constituents are widely available at no cost. Once prepared, these bricks exhibit superb water absorption properties, excellent solar absorption, and efficient photothermal conversion, all of which contribute to a pure water evaporation rate of 2.52 kg m−2 h−1 (77 % evaporation efficiency) and a salt water evaporation rate of 2.16 kg m−2 h−1 under an irradiance of one sun. Suitable pore sizes allow salt water to be converted to fresh water with only minimal salt buildup over 6 h and rapid rejection of particulates to the reservoir below. Variations in soil makeup and inclusion materials are characterized in detail, and evaporation rates are compared. This enables recommendations for the composition of an ideal adobe brick evaporator and important conclusions for the study of solar evaporation materials. While soil composition may be optimized for performance, the high evaporation rates of all samples indicate opportunities for adobe brick desalination across all biomes.

Off-grid households’ preferences for electricity services: Policy implications for mini-grid deployment in rural Tanzania

Mini-grids play a critical role in providing electricity to remote, off-grid communities in Sub-Saharan Africa. However, success of mini-grid projects can be hindered by poor cash flows and limited revenue returns. A clear understanding of off-grid households’ preferences for electricity services is a prerequisite for mini-grid stakeholders to set tariff structures and stimulate income-generating power demand to scale up mini-grid deployment. This study conducted a choice experiment survey in two off-grid villages targeted by new mini-grid projects in Tanzania to reveal heterogeneity in households’ preferences for multiple electricity service attributes. We found that households’ heterogeneous preferences were significantly associated with demographic (e.g. gender), socioeconomic (e.g. ownership of TV), and energy-related behavioural characteristics (e.g. charging devices away from home). We suggest that service-based, tiered tariffs and business models can be designed to cater for the heterogenous demands and preferences of different segments of customers. Successful deployment of mini-grids needs to consider the competition from the existing solar home systems and focus on the provision of higher tiers of electricity services. Gender equality issues should be addressed in rural electrification efforts given the significantly greater vulnerability of female-led households to higher electricity fees.

Biogenic propane production by a marine Photobacterium strain isolated from the Western English Channel.

Propane is a major component of liquefied petroleum gas, a major energy source for off-grid communities and industry. The replacement of fossil fuel-derived propane with more sustainably derived propane is of industrial interest. One potential production route is through microbial fermentation. Here we report, for the first time, the isolation of a marine bacterium from sediment capable of natural propane biosynthesis. Propane production, both in mixed microbial cultures generated from marine sediment and in bacterial monocultures was detected and quantified by gas chromatography-flame ionization detection. Using DNA sequencing of multiple reference genes, the bacterium was shown to belong to the genus Photobacterium. We postulate that propane biosynthesis is achieved through inorganic carbonate assimilation systems. The discovery of this strain may facilitate synthetic biology routes for industrial scale production of propane via microbial fermentation.

Model-based techno-economic evaluation of power-to-hydrogen-to-power for the electrification of isolated African off-grid communities

Mini-grids are expected to be the least cost option to electrify more than half a billion people living predominantly in isolated communities in sub-Saharan Africa. Providing a high reliability of power supply to satisfy paying customers is vital for the challenging business case of mini-grid owners. Therefore, renewable-based mini-grids of the third generation commonly include either diesel generators or battery storage for backup power supply.Power-to-hydrogen-to-power (P2H2P) is a promising alternative to overcome technical, financial, and social shortcomings of diesel generators and batteries. Previous research highlights the challenging economic competitiveness of P2H2P in specific case studies only. Here, we conduct a model-based techno-economic analysis on an archetypal representative mini-grid to compare the economic performance of P2H2P against the diesel generator and battery storage. We identify key parameters decisive for the competitiveness of P2H2P via sensitivity analysis.Under today's conditions, P2H2P is financially viable in 100 % decarbonized mini-grid systems. Ongoing trends of increased fuel price and P2H2P technology improvements must continue to achieve economic advantages of P2H2P over the diesel generator. However, P2H2P is competitive in locations in which the diesel price is higher than 2.6 USD/l or when P2H2P investment costs drop by >50 %, which is expected beyond 2040. Sensitivity analysis shows that increasing P2H2P system efficiency can substantially benefit the economic performance. Seasonal variations on the African continent are insufficient to create exploitable advantages of P2H2P against the short-term storage of batteries.The results suggest especially larger future PV mini-grids to combine battery storage and P2H2P rather than including common diesel generators or only including batteries when trends towards cheaper and more efficient technologies continue and diesel prices increase. Future work should investigate economic effects of the unique multi-usability of hydrogen on the mini-grid system, such as the usage as clean cooking fuel.

Life cycle assessment of a renewable energy system with hydrogen-battery storage for a remote off-grid community

Remote areas usually do not have access to electricity from the national grid. The energy demand is often covered by diesel generators, resulting in high operating costs and significant environmental impacts. With reference to the case study of Ginostra (a village on a small island in the south of Italy), this paper analyses the environmental sustainability of an innovative solution based on Renewable Energy Sources (RES) integrated with a hybrid hydrogen-battery energy storage system. A comparative Life Cycle Assessment (LCA) has been carried out to evaluate if and to what extent the RES-based system could bring environmental improvements compared to the current diesel-based configuration. The results show that the impact of the RES-based system is less than 10% of that of the current diesel-based solution for almost all impact categories (climate change, ozone depletion, photochemical ozone formation, acidification, marine and terrestrial eutrophication and fossil resource use). The renewable solution has slightly higher values only for the following indicators: use of mineral and metal resources, water use and freshwater eutrophication. The climate change category accounts for 0.197 kg CO2 eq./kWh in the renewable scenario and 1.73 kg CO2 eq./kWh in the diesel-based scenario, which corresponds to a reduction in GHG emissions of 89%. By shifting to the RES-based solution, about 6570 t of CO2 equivalent can be saved in 25 years (lifetime of the plant). In conclusion, the hydrogen-battery system could provide a sustainable and reliable alternative for power supply in remote areas.

A hybrid renewable-based solution to electricity and freshwater problems in the off-grid Sundarbans region of India: Optimum sizing and socio-enviro-economic evaluation

Stand-alone hybrid renewable energy systems have been proven as a promising pathway towards reliable and sustainable electrification of remote rural off-grid communities. The present study proposes such a system for a location near the Indian part of the Sundarbans, an area rich in biodiversity and endangered species. The hybrid system comprises solar photovoltaic modules, wind turbine, biomass generators with an electrolyzer-fuel cell-based storage system and can potentially replace the current kerosene-based arrangements, which have a significant damaging effect both on the surrounding ecosystem and the health of the residing population. The excess generation from the system is diverted to a reverse osmosis desalination system to meet the fresh water demands of the community. The sizing optimization of the hybrid configurations, performed in the MATLAB environment using a non-dominated sorting genetic algorithm-II, minimizes the cost of energy ($/kWh) and the damage to human health (DALYs) caused by the system while maintaining a demand supply reliability defined by the loss of power supply probability index. The optimized systems are analyzed based on crucial socio-enviro-economic indicators such as: cost of water ($/m3), lifecycle emission (kg CO2-eq/yr), carbon emission penalty ($/kg), ecosystem damage (species·year), job creation, and human development index. The results indicate that the best configuration has an energy cost of 0.1967 $/kWh with a water cost of 0.86 $/m3. With the least carbon emission of 56,345 kg CO2-eq/yr, 7.89E-2 DALYs of damage to human health, and 4.47E-4 species·year damage to the ecosystem, this system also imparts a positive effect on the community by creating 2.484 jobs and improving the living standards of the people with a human development index value of 0.5885. Moreover, the proposed hybrid system is able to mitigate 75,832 kg/yr of CO2 emissions, preserving the ecological quality of the region.

Untangling the impact of socio-demographic factors on energy consumption: Why is energy access difficult to achieve in off-grid island communities?

The provision of electricity to rural off-grid island communities is considered a practical initial approach to achieving Just Energy Transition. Often, these communities are powered by diesel generators running on conventional fossil fuels that typically translate to higher electricity tariffs. The use of renewable energy technologies is deemed as the practical approach to electrify these islands. However, there is a need to define how these off-grid communities consume electricity to provide a more robust approach to load demand profiling. This study proposes an alternative path analysis approach to determine causality relationships between socio-demographic attributes of households and their ownership of electrical appliances, as an approach to ascertain electricity consumption. The approach is applied in three island communities in Palawan, Philippines where electricity is provided by diesel generators. A comprehensive survey considering age, gender, income, education, household size, and employment status was done in the three island communities. Path analysis using the R lavaan package was completed to determine causality and the results were compared with traditional correlation analysis. Results of both path analysis and correlation analysis show that income and education have the strongest significance in determining household ability to own appliances, and thus electricity consumption while age is not statistically significant at all. All other factors show weak to moderate significance. The results of the research provide a critical baseline approach to load demand profiling that can help stakeholders to conduct more efficient energy planning and develop more pragmatic strategies towards 100% household electrification and Just Energy Transition.

Women and Mobile Phone Charging Business in Nigeria: A Capability Perspective

There is a growing adoption of solar home systems to support sustainable development and address poor electricity supply in sub-Saharan Africa (SSA). This has resulted in the rise of solar mobile phone charging businesses, especially in off-grid communities. An area that remains under-researched that needs to be addressed is how these solar mobile phone charging businesses provide opportunities for women in rural communities in SSA. We employ the concept of Sen's Capability Approach to evaluate how the solar mobile phone charging businesses have improved the lives of women by focusing on opportunities provided for expanding their freedom to participate in social, economic, and political activities. Our analysis shows that women's involvement in solar mobile phone charging businesses has enhanced their individual and collective capabilities to participate in development activities; however, certain contextual factors hinder the generation of these capabilities. The paper concludes with some implications for theory and practice.

Feasibility of hybrid in-stream generator-photovoltaic systems for Amazonian off-grid communities.

While there have been efforts to supply off-grid energy in the Amazon, these attempts have focused on low upfront costs and deployment rates. These "get-energy-quick" methods have almost solely adopted diesel generators, ignoring the environmental and social risks associated with the known noise and pollution of combustion engines. Alternatively, it is recommended, herein, to supply off-grid needs with renewable, distributed microgrids comprised of photovoltaics (PV) and in-stream generators (ISG). Utilization of a hybrid combination of renewable generators can provide an energetically, environmentally, and financially feasible alternative to typical electrification methods, depending on available solar irradiation and riverine characteristics, that with community engagement allows for a participatory codesign process that takes into consideration people's needs. A convergent solution development framework that includes designers-a team of social scientists, engineers, and communication specialists-and communities as well as the local industry is examined here, by which the future negative impacts at the human-machine-environment nexus can be minimized by iterative, continuous interaction between these key actors.

An Experimental Study on a Dual-Fuel Generator Fueled With Diesel and Simulated Biogas

Abstract Diesel-fueled generators are widely used for power generation in remote and/or off-grid communities. In such communities, local organic waste streams can be used to generate biogas, which can be used to replace diesel used by diesel generators to lower fuel cost and reduce greenhouse gas (GHG) emissions. Diesel-powered generators can be easily retrofitted with a biogas dosing line in the engine intake to introduce biogas, but appropriate optimization would be of great help to further improve generator performance and reduce GHG emissions. The objective of this research is to demonstrate simplified optimization methods that can reduce GHG emissions (carbon dioxide and methane) from such retrofitted dual-fuel engines under various biogas compositions. The study was conducted on a modern 30 kilowatt (kW) generator using an electronically controlled, four-stroke, four-cylinder, direct injection, turbo-charged diesel engine. The engine was operated with the factory electronic control unit (ECU) and a programmable ECU which allowed for control of the fuel injections and exhaust gas recirculation valve. Biogas was simulated by using natural gas (with more than 95% methane by volume) which was diluted with either carbon dioxide or nitrogen. This study consisted of two areas. The first one was the comparison of the engine performance when operating with biogas using the factory ECU and the programmable ECU with user-optimized fuel injection. The second one was the influence of volume fraction of carbon dioxide or nitrogen in the biogas. Test results reinforced the importance of optimizing the diesel injections when the engine was operated in the biogas-diesel dual-fuel mode to ensure complete combustion and achieve a reduction in GHG emissions. Increasing nitrogen fraction had a minimal effect on the emissions but increasing carbon dioxide fraction caused the NOx and methane emissions to decrease, and the indicated thermal efficiency to increase.

Design and Development of a Management System for Energy Microgrids Using Linear Programming

Energy is a fundamental tool for human development and this paper presents an approach that seeks to improve its use in Colombian off-grid communities. This approach is based on microgrid concepts where generation, storage, and consumption units interact with each other, and these interactions are presented through a linear programming model. In this approach, specific strategies are implemented according to the Colombian context, where some isolated communities already have diesel-based solutions for energy access, and the type of element that is studied, finding that the proposed optimization model is capable of adequately managing the loads of the microgrid,, thus improving the way in which the generated energy is stored and used through said horizon. Finally, different characteristics of the model are evaluated against multiple indicators and it is concluded that there may be much more specific strategies that improve its operation.

Microgrid System Evaluation Using Capacity Factor For an Off-grid Community in Nigeria

With the high rate of economic development, there is an increasing load demand even in rural communities and Obayantor in Nigeria. Obayantor, having zero connection to the primary grid, needs electricity. Following the community located in a tropical rejoin of Nigeria, it has enough solar energy sources. With the high price of diesel fuel, solar microgrid seems to be the best energy solution for the rural community. In this study, technical and economic analysis was carried out on the solar-based microgrid and compared with a diesel-only microgrid using MATLAB Software tool. The results show that the solar microgrid is more cost-effective and has a cheaper COE, affordable for the rural community compared with the diesel microgrid, which is more expensive to afford. The Annual system cost for the solar microgrid was lower compared with the diesel source. The result also revealed that the diesel-alone microgrid system is 4.71 times and 0.2 times more costly than the solar-based microgrid system in terms of the cost of energy and ASC, respectively. Thereby making the diesel microgrid not having technical and economic feasibility for the community.