Grid Extension Research Articles

Socio-economic and environmental analysis on solar thermal energy-based polygeneration system for rural livelihoods applications on an Island through interventions in the energy-water-food nexus

Rural electrification is constrained by grid extension infrastructural cost, isolated low rural populations, lack of anchor loads, and repayment potential of villagers while decentralized renewable energy power is constrained by high capital cost, low reliability, and non-workable business models. Solar thermal energy can produce electricity, heating, cooling, water, and fuel and has the potential for storage for livelihood applications. Hence solar thermal energy-based cogeneration and polygeneration systems have the potential for intervention in rural livelihoods with a focus on the energy-land–water-food nexus. However, standalone solar thermal systems are capital intensive and shadowed by photovoltaics. In the current work, an island in the Indian Ocean is considered for the study, and a solar thermal energy-based hybrid polygeneration system is designed with end products such as electricity, heating, cooling for food storage, and desalinating to get pure water. The turbine, VAM, pasteurization unit, and membrane distillation unit are the considered components in the present analysis. The thermodynamic properties of the key components of the polygeneration system are identified and the energy and entropy balance of the system is done. The levelised cost of production of polygeneration outputs for 25-year operational life with an accelerated depreciation of 30% of the capital cost, over 8 years is carried out. It is found that the electricity and water pricing are INR 14.71 and INR 14.01 per unit which are not attractive. Normalization is done by adjusting the price of other polygeneration outputs namely refrigeration, hot water, and pasteurizing to make the electricity and water pricing feasible to achieve an IRR of 12.99% and payback of 9 years at a 5% annual escalation. The social cost saved with the benefit of polygeneration outputs is cumulated considering value addition in the supply chain to save agricultural produce and milk, which otherwise would have spoiled. The annual carbon emissions that are curtailed with solar thermal polygeneration outputs are cumulated and found to be 434 tonnes of carbon. The social cost and environmental cost due to carbon are considered as an incentive in the cost economic economics of polygeneration system and it is found that the IRR and payback can be improved to 17.98% and 6.2 years respectively. The work recommends policy interventions to promote decentralized solar thermal polygeneration systems for impact on rural livelihoods with a focus on the energy-water-food nexus.

Understanding Braess’ Paradox in power grids

The ongoing energy transition requires power grid extensions to connect renewable generators to consumers and to transfer power among distant areas. The process of grid extension requires a large investment of resources and is supposed to make grid operation more robust. Yet, counter-intuitively, increasing the capacity of existing lines or adding new lines may also reduce the overall system performance and even promote blackouts due to Braess’ paradox. Braess’ paradox was theoretically modeled but not yet proven in realistically scaled power grids. Here, we present an experimental setup demonstrating Braess’ paradox in an AC power grid and show how it constrains ongoing large-scale grid extension projects. We present a topological theory that reveals the key mechanism and predicts Braessian grid extensions from the network structure. These results offer a theoretical method to understand and practical guidelines in support of preventing unsuitable infrastructures and the systemic planning of grid extensions.

Decision-making between hybrid renewable energy configurations and grid extension in rural areas for different climate zones

The growing population and technological developments have led to irregular houses and especially industrial facilities in developing cities. Furthermore, due to social and economic factors and the increasing massive migrations, undeveloped rural projects make irregular settlements worse. Thus, the expensiveness caused by the deterioration of the supply-demand balance makes establishment or production capacity increase of industrial facilities difficult. In this study, supplying the industrial urban facilities' demand with only grid or on-grid/off-grid HPS scenarios were investigated considering expanding and relocation outside the city. Twelve industrial cities in Turkey with various climates have been evaluated using Homer ® Pro, considering the effects of RES potential on the techno-economic parameters. The results showed that the RES potentials changed break-even distance for grid extension between 0 and 25 km. Furthermore, it has been determined that the change in the discount rate and the grid extension costs, which vary depending on the regional geographical conditions, seriously manipulate break-even distance. Particularly, it can be extended up to 55 km depending on RES potentials and grid extension capital cost. In contrast, high RES potential make unnecessary grid extension, especially where the discount rate was less than 4%. Finally, sensitivity analyses are also presented in detail.

Electricity and Livelihood in Remote India: Smart Villages Making an Impact

India has made big strides in extending the grid, now reaching more than 98% of the villages in the country. However, in parts of the extreme north and northeast India, significant populations remain unconnected due to the challenges of mountainous terrain, climate, and remoteness. Serving such remote areas involves problems with capital expense and sustainable operation and maintenance that limit grid extension as a reliable option. Off-grid solutions must overcome logistics and financial viability hurdles to provide lighting and productive use to improve livelihoods. Innovation in technology must be accompanied by innovations in business models to create sustainable and scalable solutions.

Procedure of the design of photovoltaic systems applied to ornamental lighting

Photovoltaic systems have the advantage of reducing atmospheric pollution, avoiding 𝑪𝑶𝟐 emissions. Another advantage is the energy savings they produce and that in the long term they can return the investment made. PV systems off grids are applied in remote and rural areas, where there is no electricity distribution network. The use of PV systems off grids can be included in ornamental lighting, as they have low levels of luminous efficiency due to the use of old technologies. Therefore, this study presents a procedure for the design of PV systems applied to ornamental lighting, starting from obtaining adjusted values of solar irradiance, based on estimated solar irradiance data from NASA in the city of Cuenca (Ecuador) and measured data. The critical month (maximum consumption and minimum irradiance) is selected, which corresponds to June with a value of 𝟑, 𝟕𝟔 𝒌𝑾𝒉/𝒎𝟐 . The results indicate that these systems are feasible to be implemented, due to the fact that the total investment cost is around $10.450,00 compared to a 5,2 km grid extension system that costs around $44.512,00. Finally, the responses of the PV systems off grid applied to ornamental lighting are tested in MATLAB/Simulink.

Feasibility study of CETO wave energy converter in Iranian coastal areas to meet electrical demands (a case study)

Using wave energy to supply the electrical demand of the coastal population is an exciting idea. In recent years, many wave energy converters (WEC) have been invented, researched, and used in different parts of the world. These WECs can be used alone or in a hybrid system with other renewable resources. Also, they can be used stand-alone or grid-connected to generate electricity. Iran has access to the sea from the north and south. Using wave energy to provide power can be a good solution for energy production. This study investigates the application of a point absorber WEC named CETO to supply electricity for a 300 population on the Coasts of the Caspian Sea, Persian Gulf, and Oman sea. Waves scatter diagram for three locations calculated based on the data collected by the Iranian National Center of Ocean Data. According to these diagrams, the average wave height and period on the Konarak coast in the Oman Sea were 69 cm and 5.4 s, respectively, and Konarak had the best wave condition between the desired location in terms of wave energy potential. Also, the Cost of Energy (COE) and Net Present Cost (NPC) for three areas calculated, and the lowest amount of COE and NPC occurred in Konarak. The COE range at Konarak was between 0.523 and 0.991 $/kWh for different WEC numbers. The best performance in terms of power generation and emissions reduction also occurred in Konarak; and the output power of each CETO unit was 23.01 kW, and emissions and related penalties reduced by about 24 %. Also, the effect of load change and grid extension cost on financial results sensitively analyzed, and the results presented. The obtained financial results compared with the results of some similar WECs and it was found that the obtained results differed very little from the results of other research, and were within their range.

Sparse grid method for highly efficient computation of exposures for xVA

Every “x”-adjustment in the so-called xVA financial risk management framework relies on the computation of exposures. Considering thousands of Monte Carlo paths and tens of simulation steps, a financial portfolio needs to be evaluated numerous times during the lifetime of the underlying assets. This is the bottleneck of every simulation of xVA.In this article, we explore numerical techniques for improving the simulation of exposures. We aim to decimate the number of portfolio evaluations, particularly for large portfolios involving multiple, correlated risk factors. The usage of the Stochastic Collocation (SC) method Grzelak et al. (2019)[, together with Smolyak’s (1963), Judd et al. (2014) sparse grid extension, allows for a significant reduction in the number of portfolio evaluations, even when dealing with many risk factors. The proposed model can be easily applied to any portfolio and size.We report that for a realistic portfolio comprising linear and non-linear derivatives, the expected reduction in the portfolio evaluations may exceed 6000 times, depending on the dimensionality and the required accuracy. We give illustrative examples and examine the method with realistic multi-currency portfolios consisting of interest rate swaps and swaptions.

An optimal design of wind -solar hybrid system using HOMER for drip irrigation application. A case study – Ouargla

In this study HOMER software was used as a simulation tool for the hybrid system to provide the optimal configuration of a renewable energy source capable of covering the electrical energy needs in order to irrigate 02 hectares in Ouargla region. Results have shown this region has significant potential for solar energy, reaching (2263 kWh / m2 / year). There is also significant wind speed during the spring and summer seasons. The results obtained through HOMER have demonstrated that the hybrid system consisting of 2 kW PV array, 1 number of 3 kW wind turbine, 2 kW converter, is the optimal configuration which provides the minimum cost of energy estimated with a value(COE) 0.303 $/kWh and the cost of a 25-year project estimated at (14 989 $). Finally, a comparison of the standalone system with grid extension suggests that the preference for the standalone system in isolated areas.

Providing electricity access for unelectrified people in remote areas: demonstrated to a case study in Libya

Power generation in rural areas of the world, whether through renewable energy sources or grid expansion, is critical to increasing the monetary value of life. The cost of extending the national grid or installing off-grid systems is determined by a variety of factors, including the area's location, geography, population, distance from a grid point, and land size. Due to their cost-effectiveness and ease, off-grid rural electrification systems that incorporate a variety of renewable energy sources (RESs) have become unavoidable in areas where grid connectivity is neither available nor feasible. A hybrid combination of renewable energy technologies (RETs) has demonstrated to be a viable alternative to costly grid extension in remote areas throughout the world. The purpose of this study was to plan and assess the techno-economic feasibility of providing electricity to rural Enttelat in Libya using renewable energy sources, considering 70 houses with a combined load of 875 kWh/d. Three significant outcomes were obtained because of the techno-economic design using the HOMMER tool. These three primary outcomes were chosen for their resource availability and cost-effectiveness. When several input parameters such as annual average load, scaled annual average solar resource, wind speed, annual real interest rate, and solar PV and wind component prices were varied, the sensitivity analysis revealed that hybrid system solar PV-wind renewable resource has a high potential, especially if the location is remote from a grid source.

A Rising Role for Decentralized Solar Minigrids in Integrated Rural Electrification Planning? Large-Scale, Least-Cost, and Customer-Wise Design of Grid and Off-Grid Supply Systems in Uganda

Increasing Uganda’s low electrification rate is one of the country’s major challenges. Power service is essential to achieve socioeconomic development and poverty reduction, especially in rural areas. This paper shows the advantages of using an integrated (grid and off-grid) electrification model with high geospatial, temporal, and customer-class granularity as the Reference Electrification Model (REM). In universal electrification strategies, REM will help better ascertain the role of minigrids, jointly with grid extension, solar kits, and stand-alone systems. REM has been applied to the Southern Service Territory (SST) to determine the least-cost mix of electrification modes—grid extension, off-grid minigrids, and standalone systems—that satisfies the hourly demand requirements of each customer—residential, commercial, or industrial—considering its individual location. REM incorporates the existing grid layout, the hourly solar local profile, and the catalogs of actual components for network and generation designs. The paper shows that minigrids can provide grid-like service at a significantly lower cost in many circumstances and to a considerable extent. Therefore, minigrid strategies should play a more important role in electrification planning, both transitorily and on a permanent basis, particularly when the central grid suffers from frequent and prolonged blackouts.

Nonvanishing quadrature derivatives in the analytical gradients of density functional energies in crystals and helices

It is shown that the quadrature derivatives in some analytical gradients of energies evaluated with a multi-centre radial-angular grid do not vanish even in the limit of an infinitely dense grid, causing severe errors when neglected. The gradients in question are those with respect to a lattice constant of a crystal or to the helical angle of a chain with screw-axis symmetry. This is in contrast with the quadrature derivatives in atomic gradients, which can be made arbitrarily small by grid extension. The disparate behaviour is traced to whether the grid points depend on the coordinate with respect to which the derivative of energy is taken. Whereas the nonvanishing quadrature derivative in the lattice-constant gradient is identified as the surface integral arising from an expanding integration domain, the analytical origin of the nonvanishing quadrature derivative in the helical-angle gradient remains unknown.

Ex-post design, operations and financial cost-benefit analysis of mini-grids in Ghana: What can we learn?

This paper adopted an integrated scenario modelling approach using HOMER and financial cost-benefit analysis to investigate design accuracy, power supply challenges and financial viability of two existing mini-grids in Ghana. It also examined the economic competitiveness of grid extension relative to the mini-grid plants, and offered learnings for future improvement with broader application to other developing countries. Results of the techno-economic analysis points to over-dimensioned mini-grids which should ideally be able to supply power reliably without any issues. However, altered operating decisions led to capacity constraints which is made worse by degraded batteries. Two reasons were identified to account for the oversized plants: initial load over-estimation and the influence of grant. Cost of electricity supply was found to be considerably higher than the applied tariffs making it impossible for the recovery of even operations and maintenance cost at current levels of consumption. The analysis also show that efficiently designed tariffs, coupled with the application of existing tariff regulations can significantly improve financial performance to guarantee sustainability of the mini-grid plants. The mini-grids were observed to be cost-ineffective compared to grid extension mainly due to unsuitable siting distances. Beyond efficient tariff design, other learnings from the investigation included; (1) the need to couple in-depth surveys with modular mini-grids construction to avoid over-design, (2) the need to use diesel support to mitigate cost in systems aiming for high reliability, (3) that grants can have an expansionary effect on system dimensioning and needs to be monitored, (4) that cost-cutting measures must be an integral part of mini-grid development programmes to narrow viability gap, and that, (5) overcapacity can lead to altered operating plans with consequences.

Geo-Enabled Sustainable Municipal Energy Planning for Comprehensive Accessibility: A Case in the New Federal Context of Nepal

Energy is a fundamental need of modern society and a basis for economic and social development, and one of the major Sustainable Development Goals (SDG), particularly SDG7. However, the UN’s SDG Report 2021 betrays millions of people living without electricity and one-third of the world’s population deprived of using modern energy cooking services (MECS) through access to electricity. Achieving the SDG7 requires standard approaches and tools that effectively address the geographical, infrastructural, and socioeconomic characteristics of a (rural) municipality of Nepal. Furthermore, Nepal’s Constitution 2015 incorporated a federal system under the purview of a municipality as the local government that has been given the mandate to ensure electricity access and clean energy. To address this, a methodology is developed for local government planning in Nepal in order to identify the optimal mix of electrification options by conducting a detailed geospatial analysis of renewable energy (RE) technologies by exploring accessibility and availability ranging from grid extensions to mini-grid and off-grid solutions, based on (a) life cycle cost and (b) levelized cost of energy. During energy assessment, geospatial and socio-economic data are coupled with household and community level data collected from a mobile survey app, and are exploited to garner energy status-quo and enable local governments to assess the existing situation of energy access/availability and planning. In summary, this paper presents a geo-enabled municipal energy planning method and a comprehensive toolkit to facilitate sustainable energy access to local people.

Socio-techno-economic assessment to design an appropriate renewable energy system for remote agricultural communities in developing countries

Access to clean energy for communities living in remote areas where grid extension is considered unfeasible can be provided by off-grid electrification systems using renewable energy (RE). Especially in developing countries, ensuring the appropriateness of such systems is crucial because it will determine the system's sustainability despite its limited resources. This study demonstrates the design process of an appropriate system by assessing the potential of three RE sources: solar, wind, and biomass in an oil palm and rubber-tree plantation village in South Kalimantan Province, Indonesia. A social assessment is done to avoid sustainability issues of the previously introduced technology intervention by identifying correlations between residents' attributes and satisfaction levels on a selection of social values through multiple correspondence analysis (MCA) and nonparametric methods. The techno-economic assessment and sensitivity analysis uses local data processed with the Hybrid Optimization of Multiple Energy Resources (HOMER) software. Results identified the need for a more appropriate clean energy supply for cooking, the potential role of modern technology, and access to information and communication in income generation, among other needs and opportunities that can be linked with the energy system design. The technical assessment showed that a centralized solar power plant paired with a diesel engine could provide power to the village. However, the cost of electricity (COE) is much higher than the price cap introduced by the national electricity company. This study urges a clear mechanism and a guarantee for the delivery of feed-in-tariffs (FIT) and a price cap exemption for off-grid RE systems. Furthermore, a people-centered public–private partnership business model and a remote capacity-building intervention are also needed. An appropriate energy system design must be supported by an enabling environment and supporting policies to be feasible.

An integrated waste-to-energy approach: A resilient energy system design for sustainable communities

The idea of sustainable cities and communities is a collective goal that runs across intergovernmental programs, like the United Nations Sustainable Development Goals and the African Agenda 2063 strategic framework. However, with several communities in sub-Saharan Africa and some parts of Asia having no access to electricity, this objective is still a “mirage”. Developing a resilient energy system for an unelectrified community should involve a thorough assessment and integration of the local energy resources in a decentralized generation and distribution system. For example, technologies that convert the waste generated in the community into biogas should be a part of microgrid systems. This paper thus proposes a microgrid solution for small communities where a combination of waste-to-energy, battery storage, and solar photovoltaic technologies can provide enough energy needed for the sustainable development of local communities. An unelectrified village in Nigeria has been selected as a case study. The energy demand for the village was carefully analyzed as 574 kWh/day. Techno-economic analysis of the hybrid solar PV/biogas/diesel system fit to serve this load was carried out using hybrid optimization of multiple energy resources software. The optimum hybrid system configuration was found to have a net present cost of $436,943 for 25 years with carbon dioxide emission amounting to 4,070 kg/year, compared to the traditional solar/diesel/battery microgrid which will require net present cost of $655,521 and emit 22,648 kg of carbon dioxide annually. Also, the cost of energy from this system is $0.151/kWh which is similar to the average grid tariff in the region. From the breakeven grid distance analysis, it was noted that the proposed solution is much more economical than grid extension for communities above a distance of 2.78 km to the grid.

Multi-stage optimization of rural electrification planning at regional level considering multiple criteria. Case study in Nigeria

Rural electrification should plan the multi-stage implementation of electrification systems considering different distribution options (national grid extension and decentralized off-grid systems) with different energy sources (photovoltaic, wind, diesel, etc.). Most of the existing planning assessment tools search for a static final design and only consider economical and technical criteria, although social and environmental issues have proven essential in ensuring long-term sustainability. In this context, the objective of this paper is to investigate and define how different actions of electricity extension in a region can be gradually organized to maximize the region’s overall satisfaction, and which technology options for electricity generation and distribution should be promoted on a regional scale according to economic, technical, socio-institutional and environmental criteria. The obtained solution defines, at each planning stage, to which communities should electricity access be extended and which configuration and sources are used in each community in order to maximize the total satisfaction of the region. This total satisfaction is calculated by means of multicriteria indices that evaluate the energy provided and the suitability of the chosen system designs according to stakeholders’ opinions (experts, promoters, users, among others). A mixed-integer linear programming (MILP) model is developed to solve the regional multi-stage planning. The model is validated with a computational experiment of 540 randomly generated instances; the results highlight its efficiency. Finally, it is applied to solve a case study of 544 real non-electrified communities in Plateau State (Nigeria) calculating two electrification plans (with a more and less budget-constrained scenario) which are compared with the currently available one. The results show that the proposed new plans significantly increase the total satisfaction obtained in the electrification of the region. The consideration of a less-constrained budget scenario allows the promotion of on-grid MGs based on only photovoltaic without diesel, which is the most satisfying option for the case study from a multicriteria perspective.

The renewable energy sources for electricity generation: Short review

It is critical to increase the value of life in rural areas by developing power from renewable sources or expanding the grid. The extension of the national grid or off-grid systems depends on location, geography, population, distance from grid point, and land size. Since grid connections are not always available or feasible, off-grid rural electrification systems using renewable energy sources (RES) have become unavoidable. An alternative to costly grid extensions in remote areas of the world is a hybrid combination of renewable energy technologies. This review paper discusses renewable energy sources that can generate electricity for residential and commercial.

Current scenario and outlook for biogas and natural gas businesses in the mobility sector in Brazil

Carbon neutral solutions are demanded to reduce the greenhouse gas (GHG) emissions from the mobility sector. In Brazil, alongside bioethanol, natural gas and biogas are potential solutions towards a low carbon future. While Brazilian natural gas market growth has increased due to recent offshore discoveries, its biogas potential is one of the largest in the world. Nevertheless, Brazil has currently no production of stock automobile by either gaseous fuel, despite of having the largest world flex fuel fleet (gasoline-ethanol). Therefore, the present research aims at evaluating critical points linked to the natural gas and biomethane businesses expansion in Brazil. The current scenario and outlook for energy usage is presented. RenovaBio, the recent governmental program to promote biofuels, is evaluated from the gas business point of view. And finally, the main incentive policies and regulations, price formation and limitations for the grid expansion are discussed. It is shown that biogas competitiveness as a vehicular fuel is limited mainly for the additional costs of its upgrading process to biomethane. Regarding the natural gas usage, the main limiting factor is the monopoly of production and transport in Brazil as it does not allow free competition and increases the end consumer price. Moreover, the current pipeline grid extension prioritizes the most industrialized regions and does not reach all potential natural gas users. New governmental policies and incentives were proven necessary to improve the economic viability and hence to fully benefit from the potential of both energy sources to reduce carbon footprint.

Supply preferences and productive electricity use constraints among micro and small enterprises in Bihar, India

Productive electricity use is one channel by which improvements in electricity supply contribute to economic development. Literature in this context focusses typically on larger more established firms. Here we describe electricity supply, use and preferences among micro- and small-enterprises (MSEs), which are important providers of livelihoods in emerging economies. We conduct our work using primary surveys of firm owners (N = 696) in Bihar, India. We find that reported grid electricity supply reliability is quite good, providing on average 18.7 h of electricity per day and less than one day with blackouts or voltage fluctuation per month. Nevertheless, 40% of the sampled firms have no grid connection and 75% of consume less than one kilowatt-hour per day to power basic appliances including lighting, phone charging, and fans. Using a conjoint experiment to explore firm preferences for their electricity supply, we find that supply-side improvements are unlikely to drive broad increases in grid take-up and electricity consumption. Moreover, for the majority of firms, decentralised power supply through renewable energy technologies is both adequate and acceptable to firm owners, providing a viable parallel solution to grid extension.

Feasibility Analysis and Development of Stand-Alone Hybrid Power Generation System for Remote Areas: A Case Study of Ethiopian Rural Area

This paper proposed a standalone solar/wind/micro-hydro hybrid power generation system to electrify Ethiopian remote areas that are far from the national utility grid. The aim is that it will lead to the development of renewable energy sources, using a hybrid optimization model for energy renewables (HOMER) as an optimization and sensitivity tool and MATLAB as a design tool. The system uses 100% renewable energy. This system incorporated solar photo-voltaic (PV), wind turbines, micro-hydro systems, and battery systems. The net present cost of the system is $4,377,731, incorporating capital depreciation and levelized operation and maintenance costs. During the hybrid energy system’s lifetime, the cost of a grid extension power supply is $22.185 million, which is nearly $17,808,000 more than the cost of the proposed standalone system. So, developing solar/wind/micro-hydro hybrid power generation will save $17,808,000 versus extending the national utility grid. As a result of a thorough examination of renewable energy resources, standalone solar, wind, and micro-hydro hybrid power generation is a technically and economically viable option for the case study area of Maji town.