GWh Of Energy Research Articles

Energy, exergy, environmental and economy (4E) analysis of the existing of biomass-ORC plant with capacity 150 kWe: A case study

Biomass makes a substantial contribution to Italy’s renewable energy mix. In 2018, 19,235 GWh of energy were created, continuing a trend that began three years earlier. Italy’s demand for biofuel is expected to reach 2.8 million tonnes of oil equivalent by 2025 and remain constant until 2040. Biomass combustion frequently generates high temperatures (900–1000 °C), which justifies the construction of high-temperature heat recovery units such as steam Rankine or supercritical carbondioxide (SCO2) cycles. However, these methods are only economically practical on a medium to large scale. Small-scale units have high component costs because of the high specific volume of steam, while high turbomachinery costs mostly hamper small sCO2 systems. So, another alternative way is to use an organic Rankine cycle (ORC). This study uses thermodynamic analysis to determine how much power can be achieved in terms of energy, exergy, economy and what impact on sustainability is achieved at the Bologna ORC plant. From the study results, it was found that the Bologna unit has a capacity of 150 kWe. When data was collected, the maximum power obtained was 85 kW at a temperature and pressure of 153 °C and 1.84 MPa, respectively. Biomass-ORC investment is economically competitive, with NPV and LCOE values of 238 kE and 0.93 E/kWh, respectively, and a simple payback period of 24 years for residents with yearly energy needs of 2000 h.

Novel energy management options for charging stations of electric vehicles in buildings without increasing peak demand for sustainable cities

Electric vehicles are recognised as a critical step in making the transportation sector more environmentally friendly, especially when powered by renewable energy sources. A major hindrance to their widespread adoption is the scarcity of charging stations and the absence of grid access. This study explores and examines four distinct ways to enhance the energy grid of buildings. The primary goal of these solutions is to generate more capacity without raising the peak electricity load of the building through the incorporation of energy storage technologies. The target location is Southern Ontario, Canada, which is one of most populated regions in Canada. Strategy 3 stands out as the most promising alternative, with an impressive 35 % increase in charging station capacity compared to other strategies. Using this method, it is feasible to store 353.4 GWh of energy during the summer and 480.1 GWh during the winter. In summer, the station can release 243.1 GWh, and in the winter, 345.6 GWh of energy can be efficiently used to charge electric vehicles. Strategy 4, which includes hydrogen generation and fuel cell systems, offers a competitive alternative with a 28 % increase in capacity. This method allows for charging station capabilities of 52 GW during the summer and 13 GW during the winter. The strategies emphasize the importance of adaptable capacity solutions to address variations in demand on a seasonal and daily basis while considering both economic and environmental sustainability. As the adoption of electric vehicles continues to rise, the nuanced operational aspects of these strategies are pivotal for the development of sustainable and efficient transportation ecosystems, ensuring that electric vehicle charging infrastructure keeps pace with the growing demand.

Assessment of the energy potential of municipal solid waste: A case study of Mussaka dumpsite, Buea Cameroon

A country's economic growth and urbanization often lead to environmental degradation due to the amount of waste generated. Proximate analysis was done. The objective of this study is to evaluate the energy potential of the municipal solid waste (MSW) in Buea municipality through landfill gas-to-energy and incineration technology. Methane emissions from the Mussaka dumpsite for two decades using the Inter-Governmental Panel on Climate Change (IPCC) default method (DM) and Landfill Gas Emission Model (LandGEM V3.03) models were estimated. The Buea municipality's 2022 combustible MSW generated 40,593.69 tons with a low heating value of 7.37 MJ/kg, potentially producing 20.5 GWh of energy. LandGEM and IPCC DM models predicted total methane emissions during the period 2010–2030 as 21.33Gg and 54.77Gg, with annual energy potentials ranging from 0 to 5.10 GWh and 2.91 to 15.31 GWh respectively. This study provides crucial information for waste management investors and policymakers.

Environmental and economic significance of big, old-growth trees

ABSTRACT Big, old-growth European silver fir, beech and oak on high- and medium-fertility soils in the Carpathians generate a huge increase in trunk volume, total phytomass and annual carbon accumulation (25–50 kg). Accordingly, each giant emits a lot of oxygen (65–130 kg/yr) and water vapour (40–80t/yr), and its transpiration consumes 0.03–0.06GWh of energy which can cool a hectare of a 30 m × 1 ha air layer by 0.027–0.053°C. Stands of spruce and stone pine in the high mountain zone grow more slowly; their current increase in trunk volume and material and energy impact on the surrounding air is 3–5 times less but, still, it increases over time. By increasing the number of big old-growth trees in forest stands, stand productivity and the material and energy impact on the environment can be increased by 20–40%.

Energy Saving Measures in the High-Power RF System of the European XFEL

The high-voltage modulators of the 26 klystrons in the XFEL represent the largest power consumer of the accelerator facility. The beam energy is usually 14 GeV, but a few weeks a year, lower and higher beam energies are also produced. For example, 11.5 and 16.3 GeV. Until mid-2022, the modulator voltages were set so that enough RF power for 16.3 GeV beam energy could be provided at all times. In order to save energy, the modulator voltages will now be lowered to a sufficient level for beam energies of ≤ 14 GeV. In this way, the previous power consumption of the modulators of 5 MW can be reduced up to 1 MW depending on the operation mode. Over the course of a year, this will save several GWh of energy. In the following, the relationship between the output voltage and the power consumption of the modulators is described. Afterwards, it is reported how the power consumption was reduced in various operating conditions in 2022.

Circular Economy in Wastewater Treatment Plants—Potential Opportunities for Biogenic Elements Recovery

Technologies used in municipal wastewater treatment plants (WWTPs) allow the recovery of energy and valuable elements (phosphorus, nitrogen, and organic carbon) for the soil. This article presents, in schematic form, the carbon, nitrogen, and phosphorus cycling in a WWTP with a load of 70,000 Population Equivalent and develops a spreadsheet to estimate their recovery. Biogas generation enables the recovery of 1126 Mg of organic carbon per year and the generation of 12.6 GWh of energy. The most rational form of organic waste recycling is the production of compost with fertilizing parameters, but efforts should be made to reduce iron compounds in its composition. It has been estimated that compost production provides the recovery of 30% of carbon, 98% of phosphorus, and 18% of nitrogen from the streams of these elements entering the WWTP. The possibility of partially replacing the iron coagulants used to precipitate phosphorus with waste magnesium salt is presented, leading to the precipitation of struvite, which is well absorbed by plants. The article presents the advantages of combining sewage treatment with organic waste management in WWTPs. The developed spreadsheet allows for the control of energy recovery through the quantitative selection of organic waste for fermentation.

Tidal energy extraction modifies tidal asymmetry and transport in a shallow, well-mixed estuary

Tidal energy extraction is increasingly being studied as a potential renewable energy resource in estuaries worldwide. Although it is understood that energy extraction via tidal stream turbines can modify currents and transport within estuaries, it is not clear how the underlying nonlinear physical mechanisms dictating tidal hydrodynamics are modulated. This research investigates the influence of a hypothetical tidal stream turbine array on barotropic tidal processes in a shallow, well-mixed system: the Piscataqua River – Great Bay (PRGB) estuary, using a numerical model. The modeled turbine farm includes 180 turbines which would extract an estimated 44.7 GWh of energy, annually. The tidal hydrodynamic model for the existing condition is validated with in-situ observations of currents and water level before analyzing tidal asymmetry and transport with and without tidal turbines. Results indicate that the tidal turbine array will decrease tidal elevation and current magnitudes system-wide, but generally reduce ebb currents and transport more than flood over most of the estuary footprint, thereby diminishing tidal asymmetry. The smaller asymmetric distortion compared to the no-turbine case is attributed to reductions in the storage volume of water over the estuary’s extensive tidal flat regions between low and high waters which decreases the associated nonlinear intertidal storage mechanism up to 25%. This leads to weakened ebb dominance over estuary sections from the mouth to mid-reaches, where depths are deep enough to keep the combined nonlinear shallow water and frictional effects from asserting control over the storage mechanism. Even in upstream shallow regions where depth-dependent friction controls asymmetry in both cases, the frictional mechanism is reduced only by 10% with turbines. Some environmental considerations of this work are discussed, with focus on sediment transport, water quality, and ecology.

Yamula barajının hidroelektrik rezervuar işletiminin makine öğrenimi ile simülasyonu

Large-scale reservoirs provide operational flexibility to water managers by storing water during times with higher surface water availability and releasing water when it is most needed. Most large-scale reservoirs serve for multipurpose demands, such as water supply for agricultural, urban and environmental users, hydropower, recreation, fisheries and transportation. Due to its low operating cost, hydropower generation is often maximized in energy systems with mixed hydro and thermal sources. Hydropower generation is also used to meet peak demand by advantage of operating in short notice. This study aims to simulate reservoir operations of the Yamula Dam and hydropower plant using machine learning. Located on the Kızılırmak River, the Yamula Dam is a large-scale multipurpose reservoir with its 3476 million cubic meters storage capacity. Turbine release decisions are learned with Random Forests algorithm. The developed model successfully predict reservoir releases between 2006 and 2015, with a coefficient of determination r2 value of 0.87. Model prediction results are provided, and then hydropower load, generation and revenue are calculated and results are presented. The Yamula Dam generates about 362.3 GWh of energy per year, with an annual average revenue of 14.1 million Dollars.

Template-free scalable roll-to-roll fabrication of textured transparent film for passive radiation cooling of photovoltaics

Solar panels contributed to over 115,000 GWh of energy being produced in the United States and solar panel energy consumption has increased by 27 % at the start of the 21st century. Given the decrease of photovoltaic efficiency at higher temperatures and the increasing demand for clean energy, the development of an economical technology for solar panel cooling is necessary. Passive cooling can be achieved by infrared radiating into space. Typical solar arrays require large functional areas in order to supply a significant amount of power as compared to other sources. As such, any method to help reduce the temperature of the solar panel surfaces needs to maintain manufacturing scalability for sustainable use. We demonstrate a rapid, low-cost, template-free roll coating method to fabricate photonic composite film with SiO2 nanoparticles which possess high emissivity in the atmospheric transparent window while passing visible and near infrared light to photovoltaics beneath. When facing direct sunlight at summer noon, the coatings show a 3.5°C temperature decrease without loss of photovoltaic efficiency while having hydrophobic and contamination-resistance merits.

Life Cycle Assessment of Solar Photovoltaic in India: A Circular Economy Approach.

This pioneering work employs the attributional and comparative life cycle assessment methodology to evaluate India’s ambitious target of installing 100 GW of solar energy by 2022 and the FRELP method to study the circular economy prospects of the substantial PV waste it is expected to generate. Business as usual projections suggest that the intended target will be achieved no sooner than 2029. The lower lifetime of polycrystalline PV modules combined with their lower efficiency is found to severely downgrade their environmental performance vis-à-vis monocrystalline PV modules. The end-of-life treatment of the projected 6,576 tonnes of solar PV waste, expected to be accumulated between 2034-59, indicates a recovery rate of 90.7% entailing electricity consumption, GHG emissions, and monetary cost of 678.6 MWh, 648 tonnes of CO2 eq., and USD 11.8 billion, respectively. Simultaneously, the recovery of aluminum and glass alone leads to a direct saving of 70.3 GWh of energy by eliminating raw material extraction and processing. Further, the economic value of the recovered material at USD 11.74 billion is found to have the potential to generate additional solar capacity worth 19 GW. However, making the end-of-life treatment of PV waste financially feasible would require government subsidization. A minimum amount that would equate the costs to the benefits is USD 690/MW. The study, therefore, intends to inform potential stakeholders about the environmental burden as well as the economic potential of the impending PV waste and concludes with important policy prescriptions for enabling a sustainable energy transition through the circular economy approach.

Distributed wind and solar power for grid sustainability and emission reduction

AbstractThis article intends to maximize the amount of solar and wind power produced while minimizing the tested network's annual energy loss. It also wants to improve the voltage profile and reduce the dependence on the upstream network. Two types of distributed generation sources, that is, wind DGs and solar DGs, are investigated. In this article, the network loads vary according to the local consumption pattern. This research shows that the optimal utilizing of solar and wind distributed generation sources causes energy loss to decrease by about 43% and 94%, respectively. Besides, the grid will receive 1109.49 GWh of energy from the upstream power grid without distributed generation sources. In contrast, solar and wind generation sources receive only 801.47 and 125.84 GWh, respectively. Additionally, in solar and wind scenarios, micro‐grid sends 71.62 and 102.42 GWh energy to the upstream network. Also, by calculating the emission reduction, it was observed that by installing 465.45 MW of the wind turbine units in the area under consideration, the country's CO2 equivalent is reduced by 754,586 tons, and the country's primary energy is reduced by 263,916 TOE.

Investigation on floating photovoltaic covering system in rural Indian reservoir to minimize evaporation loss

ABSTRACT The emerging floating photovoltaic (FPV) technology is the recent global attention in solar power production due to its high efficiency. Apart from the standalone FPV systems, hybridising the FPV system with the hydroelectric power plants (HEPP) will aid in increasing the power generation from HEPP by reducing the water loss through evaporation. In this study, the power generation and water-saving capacity of a model FPV system with various tilt angles, orientation and tracking mechanisms are analysed by covering 30% of the total area of Vaigai reservoir in India. The study shows that the proposed FPV plant with capacity of 1.14 MW generates 1.9 GWh of energy at its optimum tilt angle while saving 42,731.56 m3 of water annually. Further, cost analysis and carbon footprint estimation are also carried out. The results show that the FPV system will have a positive impact on the environment by saving 44,734.62 tons of CO2.

A study on transformation of multi-purpose dams into pumped storage hydroelectric power plants by using GIS model

ABSTRACT Nowadays, the continuity of all activities related to industrial production is essential for the sustainability of modern life. In order to achieve this, it is necessary to ensure the continuity of energy demand. For an energy supply to be considered as reliable, a fast and reliable response should always be provided to changing demand. Pumped storage systems can meet these needs due to their ability to store energy at times of high demand. Therefore, in recent years, many countries have increased their investments to transform existing hydroelectric power plants into pumping storage hydroelectric power plants (PHS). In this study, a GIS-based model for the transformation of an existing dam into a PHS system has been developed. The aim of this model is to determine the most suitable second reservoir location for the PHS transformation and to calculate the theoretical hydroelectric energy potential. According to the results of the study, the second reservoir location with a volume of 6,5x106 m3 was determined by transforming the Porsuk dam, which was examined as a pilot area, into a PHS. It is calculated that this reservoir can store 0.664 GWh of energy. This study will make an important contribution to the literature by presenting a holistic model approach by determining the most suitable second reservoir location and by calculating the energy potential on the transformation of existing dams into a PHS.

Electricity situation and potential development in Nigeria using off-grid green energy solutions

Sustainable supply of electricity is crucial to comfortable living in homes and attaining economic development in any country. Despite being blessed with enormous green and non-green energy resources, Nigeria has been in a quandary about adequate generation and supply of electricity. The electricity crisis has, over the years, had significant adverse impact on the nation’s socio-economic and technological development as well as standard of living of its citizens. This paper examines the problems in the electricity sector and the energy potential of green energy resources in Nigeria. The study reveals that the major source of electricity generation (natural gas) and mode of electricity transmission (a single national grid) in the country have been and are still being constrained by myriad of challenges, hence, the inability of the power sector to satisfy the electricity yearnings of Nigerians till date. The study also reveals that about 1182.375GWh of energy per day could be obtained from green energy resources in Nigeria and the provision of this quantity of energy through decentralized off-grid energy solutions would significantly increase electricity availability as well as accessibility in the country. Keywords: Electricity availability; Electricity crisis; Green electricity; Off-grid electricity

(Invited) Battery Durability and Reliability Under Electric Utility Grid Operations

Battery Energy Storage Systems (BESSs) can facilitate renewable energy sources integration onto the grid. For this application, these systems are expected to last for a decade or more, but the actual battery degradation under different real-world conditions is still largely unknown. In this work, three years of lithium titanate BESS usage in Hawai'i were analyzed. In addition, the representative usage was subjected on individual cells under controlled laboratory conditions to study the degradation mechanisms and enable life prognosis. The BESS was found to be operational 90% of the time and it stored a cumulative 1.5 GWh of energy, which represented more than 5000 equivalent full cycles on the cells. From this BESS usage data, an initial estimate of BESS degradation was provided and a representative duty cycle was developed. The analysis of the maintenance cycles indicated that these 5000 equivalent cycles induced an estimated 5-10% degradation of the single cells. The battery duty cycle was characterized based on 5 parameters: pulses duration, pulses intensity (current), state of charge (SOC) swing range, SOC event ramp rate, and temperature. The average usage consisted of several 9-second C/2 charge and discharge pulses organized to generate 5% SOC swings with a 0.75% SOC/min ramp rate at 35°C. However, extreme values such as currents up to 4C, swings of 100% SOC, and temperatures above 50°C were also recorded. Laboratory testing and analysis, in conjunction with a more thorough SOH estimation protocol, resulted in a detailed description of degradation that improved the predictions of the remaining useful battery life. Based on the BESS representative usage profile, cycle-aging and calendar-aging experiments were designed to test the degradation of the associated Li-ion cells in a controlled fashion. It was proven that the cell temperature history had the strongest impact on battery degradation followed by the C-rate and the state of charge. Interestingly, the impact of SOC, both on the cycle-aging and the calendar-aging experiments, was revealed to be counterintuitive. During cycle aging, small SOC swings were more detrimental than larger ones. During calendar aging, batteries lost capacity faster at low SOC than at high SOC. The associated degradation mechanisms and their path dependency were analyzed using incremental capacity analysis.

Integrated power generation cycle (Kalina cycle) with auxiliary heater and PCM energy storage

Kalian cycle is a modified Rankine cycle for power generation, that its working fluid is a mixture of ammonia-water instead of pure water and can be driven in higher temperatures comparing to the Rankine cycle. In this study a hybrid Kalina power cycle and solar thermal flat plate collector using phase change material (PCM) as thermal energy storage material is introduced and analyzed. Bandar Aabas (a city in south of Iran), because of its sunny days and use of the Persian Gulf sea water for cooling in the condenser has been selected. The amount of solar fraction in year is 83.8%. This integrated process requires 53.85 GWh heat load during the year that 45.13 GWh of energy per year in the system, is supplied by the sun during the hours of 7–19 and released energy from the PCM during the night from 19.01 to 6.59. Rest of the needed heat load for the integrated system of 8.72 GWh per year is provided with auxiliary heater. By using energy and exergy balance equations, all components were analyzed. According to the results, thermal efficiency of the Kalina cycle is 6.12%. Results of the exergy analyses show 23.21% of the total destroyed exergy in the cycle, occurred in one of the heat exchangers as the main component wasting exergy. Also it was found that most the exergy efficiency is related to the one of the heat exchangers and flash separator with 99.24% and 99.11%, respectively.

Battery Durability and Reliability Under Electric Utility Grid Operations:Representative Usage Aging

Battery Energy Storage Systems (BESSs) can facilitate renewable energy sources integration onto the grid. For this application, these systems are expected to last for a decade or more, but the actual battery degradation under different real-world conditions is still largely unknown. In this work, three years of lithium titanate BESS usage in Hawai'i were analyzed. In addition, the representative usage was subjected on individual cells under controlled laboratory conditions to study the degradation mechanisms and enable life prognosis. The BESS was found to be operational 90% of the time and it stored a cumulative 1.5 GWh of energy, which represented more than 5000 equivalent full cycles on the cells. From this BESS usage data, an initial estimate of BESS degradation was provided and a representative duty cycle was developed. The analysis of the maintenance cycles indicated that these 5000 equivalent cycles induced an estimated 5-10% degradation of the single cells. The battery duty cycle was characterized based on 5 parameters: pulses duration, pulses intensity (current), state of charge (SOC) swing range, SOC event ramp rate, and temperature. The average usage consisted of several 9-second C/2 charge and discharge pulses organized to generate 5% SOC swings with a 0.75% SOC/min ramp rate at 35°C. However, extreme values such as currents up to 4C, swings of 100% SOC, and temperatures above 50°C were also recorded. Laboratory testing and analysis, in conjunction with a more thorough SOH estimation protocol, resulted in a detailed description of degradation that improved the predictions of the remaining useful battery life. Based on the BESS representative usage profile, cycle-aging and calendar-aging experiments were designed to test the degradation of the associated Li-ion cells in a controlled fashion. It was proven that the cell temperature history had the strongest impact on battery degradation followed by the C-rate and the state of charge. Interestingly, the impact of SOC, both on the cycle-aging and the calendar-aging experiments, was revealed to be counterintuitive. During cycle aging, small SOC swings were more detrimental than larger ones. During calendar aging, batteries lost capacity faster at low SOC than at high SOC. The associated degradation mechanisms and their path dependency were analyzed using incremental capacity analysis.

Battery Energy Storage System battery durability and reliability under electric utility grid operations: Analysis of 3 years of real usage

Battery Energy Storage Systems (BESSs) show promise to help renewable energy sources integration onto the grid. These systems are expected to last for a decade or more, but the actual battery degradation under different real world conditions is still largely unknown. In this paper we analyze 3 years of usage of a lithium titanate BESS installed and in operation on an island power system in Hawai'i. The BESS was found to be operational 90% of the time and stored a cumulative 1.5 GWh of energy, which represents more than 5000 equivalent full cycles on the cells. This paper presents a statistical analysis of the BESS usage, develops a representative duty cycle, and provides an initial estimate of BESS degradation. The battery duty cycle was characterized based on 5 parameters: pulses duration, pulses intensity (current), SOC swing range, SOC event ramp rate, and temperature.

On the wind resource mapping of Burkina Faso

ABSTRACTIn this work, mesoscale wind resource maps, at 5-km resolution, of the country of Burkina Faso (274,200 km2) were developed using the Anemoscope and mesoscale compressible community models. Results show that the northeast region of Burkina Faso has a good wind regime at 80 m above ground level (agl), while the wind regime in other parts of the country is generally low, even at 80 m agl. In addition, the technical power potential and the potential annual energy production that can be generated from the wind in Burkina Faso are identified using analysis tools based on geographical information systems and economic constraints. Results from the technical power potential at 80 m agl show that a total of 312 MW of wind farms, generating annually a total of 741 GWh of energy, could be installed in Burkina Faso. On the other hand, a total of 4411 MW of small wind turbines (50 kW) could be installed over the territory, corresponding to an annual energy production of 7843 GWh. The Wind Atlas of Burkina Faso provides an opportunity for local stakeholders to consider wind energy for the electricity portfolio of the country.

Repurposing of disused shale gas wells for subsurface heat storage: preliminary analysis concerning UK issues

Development of many wells is envisaged in the UK in coming decades to exploit the abundant shale gas resource as fuel and petrochemical feedstock. Forward planning is therefore warranted regarding reuse of the resulting subsurface infrastructure after gas production has ceased. It is shown that this infrastructure might be repurposed for borehole thermal energy storage (BTES). Preliminary calculations, assuming an idealized cycle of summer heat storage and winter heat extraction, indeed demonstrate annual storage of c. 6 TJ or c. 2 GWh of energy per BTES well. Summed over the anticipated well inventory, a significant proportion of the UK's future heat demand might thus be supplied. This form of BTES technology has particular relevance to the UK, where the shale resource is located in relatively densely populated areas; it is especially significant for Scotland, where the resource coincides with a particularly high proportion of the population and heat demand.