Renewable Electricity Generation Systems Research Articles

Commercial EV fleet smart charging for cost reduction and renewables integration: A case study in Germany

The transition to electric mobility reduces transportation carbon emissions but presents challenges in integrating growing electricity demand with renewable electricity generation and power systems. Smart charging emerges as a key technology to minimize operational costs and support higher utilization of green electricity for electric vehicles (EVs). Market analysis indicates a trend towards dynamic electricity tariffs, incentivizing EV charging at times favourable to the electricity grid, yet existing literature fails to address smart charging technology in sync with times of lower electricity prices and higher renewables integration. This work examines different smart charging strategies for a commercial EV fleet in Germany, considering a Real-Time Pricing (RTP) tariff indexed to day-ahead market prices and renewable electricity integrations. HOMER Grid is used to model these smart charging strategies and generate new EV load profiles. Direct and indirect CO2 emissions and renewable electricity usage ratios are calculated based on detailed electricity grid and self consumption data. The resulting Levelized Cost of Energy (LCOE) is minimized, by adjusting solar PV and battery capacities. The adoption of an RTP tariff decreases the LCOE from €0.530 to €0.314 per kWh. A smart charging strategy designed to reduce peak demand and schedule charging at lower price times further reduces the LCOE to €0.283 per kWh. The lowest LCOE of €0.281 per kWh is achieved with 34.4 kWp of solar PV capacity and no batteries. The carbon impact is minimized with larger solar PV and battery capacities. The performed work indicates a favourable framework for EV charging integrators to maximize cost savings and renewable energy integration for an EV fleet charging use case.

Simulation of the optimal plant size to produce renewable hydrogen based on the available electricity

Renewable hydrogen is emerging as a valid energy alternative to the fossil fuels currently in use. Governments are developing hydrogen-based energy strategies as a tool to decarbonise the transport, industrial, energy, and residential sectors. It is estimated that by 2050, hydrogen could cover 34% of the energy demand in these sectors in Europe according to the European Commission. However, for this to happen, green hydrogen must be produced on a large scale and in an economically feasible way.The aim of this project is to model any given renewable electricity generation system so that resources are optimized to achieve the highest and most cost-effective hydrogen production possible. Based on the green energy available data available and the characteristics of the electrolysers considered, the model minimises the cost per kilogram of hydrogen produced by optimising the size of the electrolyser.Once boundary conditions were set for two renewable energy generation cases and hydrogen production was determined for an average year, the profitability was calculated as a function of two variables: electrolysis plant size and hydrogen selling price. In the case of offshore wind power, it becomes profitable to produce hydrogen starting at a selling price of $5.5/kg H2, with a minimum plant size of 55 MW.With solar photovoltaic electricity as the input of the electrolysis plant in the second scenario, for plant size range of 1 MW–300 MW, the economic balance becomes positive selling at $3.5 to $7 per kg of hydrogen produced. The results are discussed more in depth throughout the article based on the simplified calculus model presented.

Bioenergy siting for low-carbon electricity supply in Australia

In the context of renewable energy (RE) generation, biomass resources are different to other renewable resources because they can be stored and transported. These characteristics make bioenergy a dispatchable renewable energy source. While this property is recognised as being very important in supporting the global energy transition, the potential of bioenergy in renewable electricity generation systems is not well understood owing to coarse assumptions around the distribution and availability of the resource.To address this limitation, this study derived a new database of prospective new bioenergy sites in Australia based on a geographic information system (GIS)- bioenergy siting algorithm. The optimised site selection relies on high-resolution biomass resource maps, resources transport distance and other key spatial constraints.Specifically, we present biomass resources maps for bagasse, forestry and cropping residues at a spatial resolution of 5 × 5 km. Australia is on one of the top global producer of sugar cane and as such bagasse was included as feedstock for bioenergy generation. The study identified potential utilisation of 1.0, 16.6 and 28.7 million tonnes of bagasse, forestry and stubble residues respectively at over 223 prospective sites.The new biomass site database is the most comprehensive and up-to-date compilation of prospective bioenergy sites in Australia. Moreover, by considering the real-world spatial constraints, this new data set allows for a reliable appraisal of potential biomass resource utilisation. While our study is focussed on Australia the approach is broadly applicable to other jurisdictions worldwide.

Comparative life cycle environmental impact assessment of renewable electricity generation systems: A practical approach towards Europe, North America and Oceania

The choice of a power plant in different nations depends on the required resources availability, abundance, and reliability. It is evident that renewable energy generation resources provide a more sustainable solution than the fossil fuels. However, as a complete system, renewable energy generation systems also have some overall environmental impacts on humankind and ecosystems. The main objective of this paper is to addresses the environmental effects caused by different types of renewable energy generation systems through process-based life-cycle impact analysis. A comparative study is carried out among different renewable energy generation technologies which include wind, photovoltaic, biomass, and hydro power. Life-cycle impact analysis has been carried out by Institute of Environmental Sciences (CML), Eco-indicator 99, Cumulative Energy Demand (CED) and Ecopoints 97 approaches. The superiority of this work is creating a comprehensive life-cycle inventory following a reliable global database, assessing the impacts for about 10 midpoint impact categories and three endpoint indicators, and taking account of the fossil-fuel-based energy consumption rate of each plant. The key findings reveal that photovoltaic power plants have the highest environmental impacts in the types of ozone layer depletion, fresh water aquatic ecotoxicity and marine aquatic ecotoxicity, while biomass plants impact on the categories of abiotic depletion, global warming, photochemical oxidation, acidification, and eutrophication. Moreover, the wind power plants have the more significant environmental effect on human toxicity and terrestrial ecotoxicity types. Overall, hydropower plants are found to be much more environment-friendly than other renewable electricity generation systems.

Country-specific cost projections for renewable hydrogen production through off-grid electricity systems

Renewable hydrogen is increasingly recognized as one of the key decarbonisation options compatible with the EU's climate neutrality goal. We quantify possible cost reductions for renewable hydrogen production until 2050 through electrolysis with off-grid renewable electricity generation systems. We focus on the use of solar PV and on- and offshore wind energy in 30 European countries. We project that towards 2050 hydrogen production costs can fall below 2 €/kg in several countries in Europe. Hybrid configurations, consisting of both onshore wind and solar PV electricity generation, generally result in lower renewable hydrogen production costs. Systems with a relatively high level of full load hours benefit from a reduced share of investment costs for the electrolyser component. The levelized cost of hydrogen produced via solar PV systems can only compete with wind-based systems when significant electrolyser cost reductions are realized, despite the ultimately low expected levelized costs of solar PV-based electricity generation. The novelty of this analysis is that it proffers an overview of the dependencies of the costs of green hydrogen production, and how these costs could decrease over the forthcoming decades across a large set of European countries. Specifically, we show how the dynamics behind the projected renewable hydrogen production costs per country highlight the role that technological learning could have in identifying the most suitable locations for hydrogen production.

Analysis and proposal of energy planning and renewable energy plans in South America: Case study of Ecuador

This research evaluates the South American Electric Energy System and its features related to the inclusion of renewable energies into the transition processes to leave fossil fuel-based energy systems behind. Analysis of the Ecuadorian case is a novel approach because in the first instance its matrix was based on the use of fossil fuels, with dire consequences of pollution, especially in the Amazon. Interest is growing in terms of economic, legal and social renewal, leaving behind the rapidly depleting oil systems which have been a polluting source. This research presents a novel analysis of the state of the Ecuadorian electricity system and after a flexible analysis in Energyplan, proposes the feasible renewable energy sources and their shares to guarantee the new demand in 2050 and an Ecuadorian 100% renewable electricity generation system, having a positive impact on the monetary, increasing production levels and improving the quality of life of its citizens. Installed power by 2050 is expected to be 20 GW and will require an annual production of 72.24 TWh. Hydro (6.02 GW), solar PV (5.7 GW) and wind (5.61 GW) will have the most impact on the Ecuadorian energy matrix. The average production cost of 1 MWh will be approximately 18 US cents.

Towards an integrated design of renewable electricity generation and storage systems for NZEB use: A parametric analysis

Although nearly zero energy buildings have attracted growing research attention, literature analysis shows that only a limited number of researches try to couple load match/grid interaction issues and environmental impacts in early design stages. The study proposes a novel multidisciplinary design approach that allows to integrate these two conflicting aspects aiming to find trade-offs. The proposed approach has been applied to a building case study, equipped with a photovoltaics system without energy storage. The results show that even though on yearly basis the energy use (5,290 kWhe) is largely overcome by the on-site energy generation (8069 kWhe), an oversized PV system alone may not be the best solution for reducing the environmental impact of the building sector, besides not being very efficient in improving load match. Afterwards, a parametric analysis was carry out analysing three redesign scenarios, obtained varying the sizes of the PV system and installing different sizes of the storage systems. The results show that the use of storage systems, in addition to decrease the grid dependency, can increase the environmental benefits arising from the renewable energy sources (e.g. there is a decrease of global warming potential of 48%, compared to the base case, with 5.28 kWp PV system and 10 kWh storage system). Conflicting results are found according to specific impact categories and this suggests the need for a holistic approach, including different domains and indicators. In this context, the proposed approach can contribute to the transition toward low-carbon energy technologies, by supporting researches and designers to take environmentally sound considerations.

Conceptualization and techno-economic evaluation of municipal solid waste based microgrid

To find a sustainable municipal solid waste (MSW) management and renewable electricity generation system is need of the hour. In modern hybrid electricity generation systems, the use of MSW on priority is not evaluated yet. To satisfy this need, a small scale MSW based microgrid is proposed and evaluated in economic and reliability terms. First, the waste of the selected city is characterized considering four seasons summer, spring, autumn and winter for a complete year. Then a microgrid system is designed using MSW processing techniques namely, anaerobic digestion (AD) and gasification that are further integrated with solar photovoltaic (PV) system, battery and the main grid. The size of the microgrid is optimized using an artificial bee colony (ABC) algorithm targeting the configuration that meets the desired system reliability requirements with minimum cost. The proposed system found as a sustainable approach to process the MSW of a small city (0.1 million population) and a reliable mean to fulfill the electricity demand of a village having 225 houses in India. The annualized system cost (ASC) of the proposed hybrid system found to be INR 5760919 with levelized cost of electricity (LCOE) 5.65 INR/kWh (0.0737 USD/kWh). The total MSW landfilling avoided cost is 451898.9 INR/year that is 17% of its processing cost.

Modelling utility-aggregator-customer interactions in interruptible load programmes using non-cooperative game theory

Aggregator-activated demand response (DR) is widely recognised as a viable means for increasing the flexibility of renewable and sustainable energy systems (RSESs) necessary to accommodate a high penetration of variable renewables. To this end, by acting as DR aggregators and offering energy trading capabilities to smaller customers, energy retailers unlock additional sources of demand-side flexibility to ensure the cost-optimal operation of RSESs. Accordingly, a growing body of literature has highlighted the ways in which non-cooperative game theory could be used to reduce the gaps between modelled and real-world results for aggregator-mediated DR schemes. This paper aims to contribute to the trends of giving a realistic grounding to research on distributed DR-integrated energy scheduling by using insights from non-cooperative game theory to determine: (1) the optimal trade-off between importing electricity and utilising DR capacity in grid-tied RSESs, (2) the impact of the price elasticity of DR supply of different customer classes – especially, new sources of electricity demand, such as e-mobility – on the system-level dispatch of DR resources, and (3) the financial implications of harnessing the flexibility potential of a large number of end-consumers across different sectors. Accordingly, the principal goal of the paper is to develop an operational planning optimisation model that can be directly applied to real-world aggregator-mediated, market-based demand-side flexibility provisioning domains. To this end, this paper presents the first DR elasticity-aware, non-cooperative game-theoretic DR scheduling model that: (1) yields the best compromise solution between imported power and dispatched DR resources from the utility’s perspective, (2) characterises the utility-aggregator-customer interactions during the market-based DR trade process with several customer categories involved, and (3) disaggregates the total sectoral load on the system to individual end-consumers, which has potential implications for pre-feasibility and business case assessments. The application of the model to a conceptual micro-grid for the town of Ohakune, in New Zealand, demonstrates its effectiveness in reducing the daily system operational cost (over the critical peak hours) by ~66% and ~47% on a representative summer and winter day, respectively. Importantly, the paper provides statistically significant evidence supporting that activating the flexibility potential of small- to medium-scale end-consumers through specifically defined third-party aggregators in a market-based approach – that is aware of strategic interactions among instrumentally rational economic agents involved in the dispatch and delivery of DR resources – plays a significant role in the cost-optimal transition to 100%-renewable electricity generation systems within the smart grid paradigm.

Towards a 100% renewable energy electricity generation system in Sweden

Swedish government’s target is to have 100% renewable electricity production by 2040. Currently, hydropower contributes the majority of renewable electricity generation of the country. The wind power capacity has increased significantly in the past decade. In this paper, practical data is used to study the possibility of reaching the 100% renewable electricity generation goal by replacing existing thermal generations with wind power generations. It is found that the Swedish electricity generation system can reach 100% renewable by tripling the existing wind power capacity combined with the existing hydropower in the country. Based on current growth rate of wind power installation, the goal could be reached within 20 years. Hourly simulation shows that 100% renewable energy generation system composed by wind power and hydropower satisfy hourly operation requirements.

Comparative Life Cycle Environmental Impact Assessment of Renewable Electricity Generation Systems: A Practical Approach Towards Europe, North America and Oceania

This paper addresses the comparative environmental impacts of four different renewable-power plants, namely solar, wind, biomass and hydropower plants. Life-cycle impact analysis has been carried out by Institute of Environmental Sciences (CML), Eco-indicator 99, Cumulative Energy Demand (CED) and Ecopoints 97 methods, using the Ecoinvent database and SimaPro software. The superiority of this work is creating a comprehensive life-cycle inventory following a reliable global database, assessing the impacts for about 10 midpoint impact categories and three endpoint indicators, and taking account of the fossil-fuel-based energy consumption rate of each plant. The results show that photovoltaic power plants have the highest environmental impacts in the types of ozone layer depletion, fresh water aquatic ecotoxicity and marine aquatic ecotoxicity, while biomass plants impact on the categories of abiotic depletion, global warming, photochemical oxidation, acidification, and eutrophication. Moreover, the wind power plants have the more significant environmental effect on human toxicity and terrestrial ecotoxicity types. Overall, hydropower plants are found to be much more environment-friendly than other renewable electricity generation systems.

Life cycle assessment of a vanadium flow battery

Battery storage technologies have been showing great potential to address the vulnerability of renewable electricity generation systems. Among the various options, vanadium redox flow batteries are one of the most promising in the energy storage market. In this work, a life cycle assessment of a 5 kW vanadium redox flow battery is performed on a cradle-to-gate approach with focus on the vanadium electrolytes, since they determine the battery’s storage capacity and can be readjusted and reused indefinitely. The functional unit is 1 kWh stored by the battery. The initial results show that the environmental hotspots reside mainly in the structural and material components of the battery, evidencing the need for alternative or recycled materials, preferably produced locally. Since the quantity of electrolytes determine the amount of storable electricity, an analysis was conducted on the variation of the impacts with the increase of storage capacity. An alternative scenario with reused electrolytes was also performed. Results show that with the increase of storage capacity, the contribution of the electrolytes to the impacts decrease significantly by stored kWh. In the reused electrolytes scenario, impacts were reduced mainly for the Acidification and Mineral, fossil and renewable resource depletion categories.

A Complete Power Demand Distribution using Renewable Electricity Generation System for India by Incorporating Solar, Wind, Thermal and Biomass Energy Resources

In India the electricity demand is growing rapidly day by day due to various increasing residential, official and organizational buildings which requires more power. Electricity generation system is dominated by a hybrid renewable energy resources like wind and solar, approximately 35% from 2007 to till now, still power shutdown is applied compulsory by the Indian Government. In order to improve the amount of power generation to 100% with increased thermal, fossil-fueled, and bio-gas power generation is converted into complete solar, wind and thermal including peaking options. In order to fulfil the demand, the wind capacity is increased from 35% into 100% by incorporating solar and thermal. Incorporating various energy systems into stand alone power grid, the highest power demand can be fulfilled. This paper applied an application for mixing various energy resource for increasing the power generation and production.

Life-cycle impact assessment of renewable electricity generation systems in the United States

Renewable electricity generation technologies provide a more sustainable solution than the non-renewables. However, as a complete system, renewable energy generation systems have some overall environmental impacts on humankind, resources and ecosystems. This paper will address the environmental effects caused by different types of renewable plants through life-cycle assessment. A comparative study is done among solar PV, biomass, and pumped storage hydropower plants in the United States. Life-cycle impact analysis has been carried out by the Eco-indicator 99, TRACI (Tool for the Reduction and Assessment of Chemical and other Environmental Impacts), CED (Cumulative Energy Demand), Ecopoints 97, RMF (Raw Material Flows) and IPCC (Intergovernmental Panel on Climate Change) methods, using the SimaPro software. The impacts are considered in 10 mid-point impact categories and three end-point indicators. The results show that pumped storage hydropower plants have the highest impact on human health (7.74E-05/kWh) and the ecosystem (3.35E-06/kWh), whereas biomass plants have the maximum effect on resources (4.79E-07/kWh). Overall, the solar PV plants are found to be much more environment-friendly than other renewable electricity generation systems. These findings will guide investors in installing sustainable and clean power plants.

Interactive energetic, environmental and economic analysis of renewable hybrid energy system

One of the commitments of the European community is to increase the share of energy produced from renewable sources in order to minimize costs and risks, or that the society has to bear to produce electricity, in addition to compliance with European pollutant gas (CO2, SO2, NOx and PM) objectives. An ever-increasing body of research aims to study the actual energy savings of buildings with systems of renewable energy production implemented with storage systems, evaluating the potential energy savings. To date, however, the analysis of the environmental impacts of the total life cycle was not taken into account. Thus, no assessment has been made whether the amount of energy saved (esaved) outweighs the energy needed for production, use and disposal (einvested). This study presents an approach for the analysis and evaluation of the energy flows, environmental impacts and cost of a new modular and integrated system of renewable electricity generation and intelligent electrochemical storage systems, that allows auto-production and self-consumption of electricity in residential buildings (smart grid). The results show that the total impact depends on the configuration chosen, from the consumption profile and the types of users. If the duration of use is short and the savings achieved are small, the expected benefits will not always be achieved, in terms of costs for the user and the environmental impact.

A hybrid approach of VIKOR and bi-objective integer linear programming for electrification planning in a disaster relief camp

In this paper, we provide a model which optimizes the allocation of electricity generation systems, in terms of their number and location, in a disaster relief camp. The objectives that this model takes into account are minimization of the total cost of the project and prioritization of those generation systems that perform favourably. Energy and specifically electricity plays an important role in the provision of essential needs like lighting, water purification, heating, ventilation and medical care for displaced people. Disaster relief camps are commonly considered as off-grid projects, so individual generation and control systems are the main means of electrification. To support decision makers in electrification planning for temporary and semi-temporary camps, we propose a bi-objective integer linear programming model. The performance evaluation of technologies such as fuel generators, wind turbines and solar panels is conducted with an MCDM (VIKOR) approach. The model is applied on a hypothetical but realistic map site with data regarding commercially available equipment. The better performance of solar panels regarding the evaluation criteria have made them the dominant applied source of renewable electricity generation system and together with application of micro-grids in the model they have proven to reduce the cost of generation significantly. However, installing fuel generators have been found necessary for facilities which can cause a remarkable damage in case of electricity interruption. The model is promising in helping relief aid agencies to design an electrification project with minimum cost and maximum utility.

Investor focused placement and sizing of photovoltaic grid-connected systems in Pakistan

Abstract The world is moving toward renewable rich electricity generation systems. Pakistan being the sixth most populous country in the world and having median age of 21 years requires extensive resources for the next couple of decades to fulfill its energy requirements. Punjab is the largest province of Pakistan with 60% of total population and consumes about 80% of the electricity. The province does not have a lot of hydro and wind potential, but it has tremendous opportunity to utilize solar energy to fulfill its energy needs. In this paper, we explore the solar energy production possibilities in the province. Our objective in this paper is to find the best locations to install utility-scale solar power plants to fulfill 30% of energy needs by 2030. In addition to the technical feasibility of solar PV power plants, we also look at the economic aspects of such plants. To this end, we look at the complete life cycle of a solar PV power plant. Using data from an existing solar PV power plant we derive Profitability Index (PI) of various possible locations. According to our results, the transmission line losses range between 0.7% and 12.2% depending on the load and length of the transmission lines. Using data from transmission line losses the PI of potential utility-scale solar PV sites ranges between −9.11% and 69.65% based on various economic factors. These results provides detailed information on the best places to establish utility-scale power plants from technical as well as economic perspective.

Performance study of SOL&PID system for the degradation of Acid Red 26 and 4-Chlorophenol

To increase the photocatalytic reaction rate and make full use of electricity generated by photovoltaics (PV), a water purification system (SOL&PID) with solar and ultraviolet-light emitting diode (UV-LED) powered by a hybrid PV photocatalytic reactor was designed and tested in this paper. The SOL&PID system is based on Solar Water Purification and Renewable Electricity Generation system (SOLWAT). Photovoltaic and photocatalytic performances of SOL&PID system were evaluated in comparison with SOLWAT by the degradation of Acid Red 26 (AR 26) and 4-chlorophenol (4-CP) using suspended TiO2. To assess the directly-coupled performance between PV and UV-LED array, the power consumption percentage of UV-LED array from the maximum output power of PV was analyzed. The results show an adequate coupling between the UV-LED array and the photovoltaics. More than 92% of the maximum output power generated by PV modules is used to drive the LED array. The photocatalytic reaction rate constants in SOL&PID system increase respectively 29–37% and 31–78% during AR 26 and 4-CP experiments, in comparison with SOLWAT system. Besides, the SOL&PID system achieved lower solar module temperature and lower UV-LED pin temperature than the reference systems by the addition of flow channel.

Economic Feasibility of Renewable Electricity Generation Systems for Local Government Office: Evaluation of the Jeju Special Self-Governing Province in South Korea

While environmental and energy concerns have become global issues, the government of South Korea has made notable efforts and formulated plans for the diffusion of renewable energy generation facilities for the nation’s public and governmental institutions. Accordingly, Jeju Island has become one of the most promising locations for utilizing renewable energy resources. This study aims to propose potential configurations for renewable energy generation facilities (mainly solar and wind energy facilities) in response to the electricity demand of the main local governmental offices of Jeju Special Self-Governing Province. The study utilizes the hybrid optimization of multiple energy resources software to simulate two optimized configurations for generation at a cost of energy of $0.306 per kWh (independent) and $0.204 per kWh (grid-connected) with 100% renewable fraction for the island. The implications of the simulation results and limitations of the study are discussed.

An economic evaluation of renewable and conventional electricity generation systems in a shopping center using HOMER Pro

This paper presents the methodology and results of the simulation and optimization of renewables and non-renewables energy system for supply to a shopping center as an alternative to the electric grid consumption, so that to determinate the optimal system. The fundamentals equations used to estimate the operational costs are presented. The software used to simulate and optimize the purposed system is HOMER Pro®, this software can simulate energy systems with renewable fractions and optimize those components to obtain the best system to use. In addition, the renewable systems they have the lowest annual operation cost and total operation cost in the simulated case study, therefore those systems should be consider as the better option to take as an alternative to the electrical grid consumption, but the non-renewable systems could be a great solution if the problem lies in obtaining an emergency plant, capable of generating large amounts of energy in a short period of time. Finally, that the renewable electric generating devices are the better option to use as an alternative to the electric grid consumption but it is recommended the use of an emergency plant with the final purpose of supply large amounts of energy if the situation requires it and this emergency plants should be natural gas electric generating devices or diesel electric generating devices.