Pages: 1 - 14 Abstract: AbstractThis study proposes a conceptual design of green hydrogen production via proton exchange membrane electrolysis powered by a floating solar photovoltaic system. The system contributes to industrial decarbonization in which hydrogen blending with natural gas is proposed as an approach to smooth the energy transition. The proposed design addresses the challenge of supplying a continuous flow-rate of green hydrogen, which is typically demanded by industrial end users. This study particularly considers a realistic area required for the installation of a floating solar photovoltaic system. To enable the green hydrogen production of 7.5 million standard cubic feet per day, the required structure includes the floating solar photovoltaic system and Li-ion batteries with the nominal capacities of 518.4 megawatts and 780.8 megawatt-hours. This is equivalent to the requirement for 1 524 765 photovoltaic modules and 3718 Li-ion batteries. The assessment confirms the technical viability of the proposed concept of green hydrogen production, transportation and blending. While the present commercialization is hindered by economics due to a high green hydrogen production cost of USD 26.95 per kg, this green hydrogen pathway is expected to be competitive with grey hydrogen produced via coal gasification and via natural gas steam reforming by 2043 and 2047, respectively. PubDate: Fri, 28 Jun 2024 00:00:00 GMT DOI: 10.1093/ce/zkae032 Issue No:Vol. 8, No. 4 (2024)
Pages: 15 - 33 Abstract: AbstractThis study investigates the optimization of physical parameters in a parabolic trough collector receiver unit to improve its thermal and optical performance. The parameters include the transmissivity, reflectivity, absorptivity, emissivity and thermal conductivity of the outer cover and absorber pipe. This study utilizes a novel experimental design and a simulation model that accounts for the infrared reflectivity inside the receiver. The simulation results were validated by the experimental data, with a maximum deviation of 8%. The study analyses the effects of varying the physical parameters on the heat transfer fluid temperature, total plant efficiency, temperature profiles, temperature gradients and thermal stress. The study finds that increasing the reflectivity and decreasing the emissivity of the outer cover and the absorber pipe significantly enhance the performance, with maximum increases of 25.8% and 26.5% in total efficiency, respectively. The study also finds that increasing the thermal conductivity of the absorber pipe reduces the temperature gradients and thermal stress, with maximum decreases of 42.2% and 29%, respectively. This study provides valuable insights for optimizing the receiver design and operation in solar–thermal systems. PubDate: Tue, 02 Jul 2024 00:00:00 GMT DOI: 10.1093/ce/zkae033 Issue No:Vol. 8, No. 4 (2024)
Pages: 34 - 39 Abstract: AbstractAlthough fossil fuels are widely used to meet energy needs, intensive research has been carried out in recent years on hydrogen production from renewable sources due to their decrease over time and environmental pollution concerns. Biofuel cell technology is one of the promising current technologies. It has been proven that various microorganisms produce energy through their natural metabolism, and that energy production is produced in biofuel cells by exoelectrogenic microorganisms that can transfer electrons to an electrode surface. Although it has been stated that employing human cells to generate energy is feasible, it is unknown whether doing so would enable the production of hydrogen. Within the scope of this perspective article, the issue of hydrogen production in bioelectrolysis cells using human cells will be discussed for the first time. Optimizing hydrogen production in bioelectrolysis cells using human cells is important in terms of contributing to hydrogen technologies. Within the scope of the article, promising human cell lines for hydrogen production are emphasized and hydrogen production potentials in bioelectrolysis cells using these cell lines are discussed. In conclusion, some human cells can be used for hydrogen gas production in bioelectrolysis cells due to their bioelectrochemical and metabolic properties. PubDate: Thu, 04 Jul 2024 00:00:00 GMT DOI: 10.1093/ce/zkae034 Issue No:Vol. 8, No. 4 (2024)
Pages: 40 - 48 Abstract: AbstractSolid biomass dominates as the primary source of cooking energy, especially in rural households of Nepal. The use of solid biomass has a detrimental effect on health, exacerbates the burden of biomass collection, and hampers access to clean energy. Understanding the factors influencing the choice of modern cooking fuels is crucial to improving energy security and resilience and easing the transition to clean fuels. This study evaluates technological choices for the transition in cooking energy from the perspective of experts working in the government, non-government, and academia sectors. A structured questionnaire survey was prepared with five criteria and nine cooking technology options. Fifty-one experts responded to the survey, and their responses were analyzed using the analytical hierarchy process. The study reveals that efficiency and capital cost are the primary criteria for selecting cooking technology. The most suitable clean cooking technology is an induction stove followed by a hot plate, while the least preferred technology is a Bayupankhi stove followed by two-pothole mud improved cooking stoves. To ensure the robustness of the method, sensitivity analysis was performed on the two primary criteria efficiency and capital cost of the cooking technology. The analysis revealed robust and consistent rankings of technologies. This study should help create a conducive environment for relevant stakeholders and policymakers to formulate and implement relevant policies and strategies to accelerate the cooking energy transition in Nepal. PubDate: Thu, 04 Jul 2024 00:00:00 GMT DOI: 10.1093/ce/zkae035 Issue No:Vol. 8, No. 4 (2024)
Pages: 49 - 60 Abstract: AbstractWind power technology has been widely used due to its characteristics of environmental protection, sustainability and low cost. The yaw system plays a vital role in improving the energy capture efficiency of a wind turbine. However, the method of layout determination is lacking in the yaw system. To solve this problem, a method that combines the Delphi method and the analytic hierarchy process was proposed in this study. Twelve evaluation indexes, including transmission efficiency, ratio range, operating temperature range and others, were identified by screening 18 technical indicators using the Delphi method. Subsequently, the evaluation system of the yaw system was established. Then, six configuration schemes were selected. Experts’ scores of schemes were collected according to the evaluation system and the score matrix of evaluation indexes was obtained. The hierarchical model of the evaluation indexes of the yaw system was established and the comprehensive weight was obtained by using the analytic hierarchy process. After calculating the comprehensive evaluation score, the comprehensive evaluation result was obtained. The 2Z-X(A) negative mechanism, which achieved the highest score of 0.9227, is the optimal scheme. A new method and specific process are provided for designers. The research gap in the scheme selection method for yaw systems is filled. PubDate: Thu, 04 Jul 2024 00:00:00 GMT DOI: 10.1093/ce/zkae038 Issue No:Vol. 8, No. 4 (2024)
Pages: 61 - 78 Abstract: AbstractPyrolysis is a thermal conversion process in the absence of air to derive energy components from the residues. Renewable-energy technologies will play a major role in addressing future challenges related to environmental safety and energy security. One of the many easily available renewable energy sources is biomass—an organic material that is thought to be carbon-neutral. Pyrolysis technology is a thermochemical process that can be used to produce useful products from biomass, such as biochar, bio-oil and combustible pyrolysis gases. The structure and relative product yield are impacted by the pyrolysis method employed. This article evaluates different approaches for biomass pyrolysis. Fast, slow and advanced pyrolysis methods using various pyrolyser reactors have been studied in the literature and are provided to increase the variety and use of these methods in upcoming studies and research. Slow pyrolysis can lead to increased ecological well-being, as it increases the amount of biochar produced using auger and rotary-kiln reactors. Rapid pyrolysis, mainly in fluidized-bed reactors with bubbling and rotating circulation, can be used to obtain bio-oil. Advanced pyrolysis methods offer a good probability of yielding great prosperity for specific applications. The selection of a pyrolysis process is based on the required output in terms of solid, liquid and gaseous fuels, and the parameter plays a crucial role in the pyrolysis performance. PubDate: Fri, 05 Jul 2024 00:00:00 GMT DOI: 10.1093/ce/zkae036 Issue No:Vol. 8, No. 4 (2024)
Pages: 79 - 89 Abstract: AbstractClimate change is predicted to significantly impact solar energy generation, which is particularly concerning given that photovoltaic (PV) energy is critical to the global transition to clean energy in underdeveloped countries. This study analyses the PV potential variations in Colombia using a Coupled Model Intercomparison Project Phase 6 (CMIP6) multi-model ensemble approach under two shared socio-economic pathway scenarios for the near (2025–50) and far (2051–2100) future. During the near-future period, the Pacific, Andean and Orinoquía regions are expected to experience a decrease in PV potential ranging from 10% to 23% for all shared socio-economic pathways. It will be particularly noticeable during the March/April/May and June/July/August seasons. On the other hand, CMIP6 estimations indicate a 1–4% increase in PV potential across the Amazon region during the June/July/August and September/October/November seasons. For the far future, it has been projected that the Pacific, Andean and Orinoquía regions may experience a significant decline in solar power generation due to increased cloud cover and reduced sunshine. The decrease in PV potential during the June/July/August season could range from 8% to 27% for all considered scenarios, with the Pacific region being the most affected. The Pacific region is projected to experience a decrease ranging from 10% to 35% for all seasons. It is worth noting that there are noticeable differences in PV potential across various regions, which can result in changes in cloud cover and atmospheric aerosols. Overall, the study provides valuable insights into the PV potential in Colombia and highlights the importance of considering regional variations and climate change scenarios in future energy planning. PubDate: Fri, 05 Jul 2024 00:00:00 GMT DOI: 10.1093/ce/zkae037 Issue No:Vol. 8, No. 4 (2024)
Pages: 90 - 102 Abstract: AbstractRenewable energy has penetrated power grid enterprises on a large scale. Due to the intermittency and volatility of renewable energy generation, it is necessary to build new flexible grid-side resources to ensure the safe and stable operation of the power grid, which will cause great pressure on cost allocation for power grid enterprises. This article considers four types of flexible grid-side resources and constructs a dual-level configuration optimization model for flexible grid-side resources under the penetration of renewable energy. Based on the configuration results, the cost scale of flexible grid-side resources is estimated and an improved ancillary service cost allocation model based on the Shapley value method is proposed to smooth the allocation of ancillary service costs in the cost of flexible grid-side resources between the two main bodies of renewable energy and load. The calculation results show that, when the penetration rate of renewable-energy power is 30% and 35%, respectively, the cost of flexible grid-side resources is 9.606 billion yuan and 21.518 billion yuan, respectively. The proportion of ancillary service costs allocated to load is relatively high—about five times that of the ancillary service costs allocated to renewable energy—and the higher the penetration rate of renewable energy, the higher the proportion of ancillary service costs allocated to renewable energy. PubDate: Mon, 08 Jul 2024 00:00:00 GMT DOI: 10.1093/ce/zkae039 Issue No:Vol. 8, No. 4 (2024)
Pages: 103 - 110 Abstract: AbstractLow-carbon hydrogen is expected to play a key role in realizing net-zero and sustainable development plans. Nonetheless, there is a gap between the cost of producing low-carbon hydrogen and its potential users’ willingness to pay for such hydrogen. To implement support for the development of the industry, we propose using low-carbon hydrogen long-term agreements allocated through auction mechanisms. The objectives are 2-fold: (i) matching supply and demand volumes considering the time horizon and geographical delivery point specification and (ii) allocating the subsidy. This perspective article innovates by proposing a reference price indexed to liquid to natural-gas prices, which is the main product that low-carbon hydrogen aims to substitute. The premium and the production cost are defined through a double-sided auction. This aims to minimize the public policy funds required to incentivize the low-carbon hydrogen market while facilitating long-term agreements and mitigating price risks that may hinder investment. PubDate: Mon, 08 Jul 2024 00:00:00 GMT DOI: 10.1093/ce/zkae040 Issue No:Vol. 8, No. 4 (2024)
Pages: 111 - 134 Abstract: AbstractPipelines produce vibrations during fluid or gas transportation. These vibrations are less likely to cause structural failure as they exist with a small magnitude and can be harvested into useful energy. This paper presents a study on the piezoelectric energy-harvesting method converting mechanical energy from pipeline vibration into electrical energy. The performance of the serpentine-shaped piezoelectric cantilever beam was observed to check whether the design can produce the highest output voltage within the allowable vibration region of the pipeline from 10 to 300 Hz through finite element analysis using COMSOL Multiphysics software (Supplementary MaterialSupplementary Material). In addition, this study investigates the energy-harvesting potential of the proposed design under real pipeline vibration conditions through a lab vibration test. The harvested energy output is evaluated based on various vibration frequencies and amplitudes, which gives an idea of the device and its performance under different operating conditions. The experiment result shows that the energy harvester produced an open-circuit voltage of 10.28–15.45 V with 1 g of vibration acceleration. The results of this research will contribute to the development of efficient piezoelectric energy harvesters adapted for pipeline environments. PubDate: Wed, 22 May 2024 00:00:00 GMT DOI: 10.1093/ce/zkae042 Issue No:Vol. 8, No. 4 (2024)
Pages: 135 - 146 Abstract: AbstractElectricity production from photovoltaic (PV) panels is maximized when the operating point is located at the maximum power point thanks to dedicated controllers. These controllers are driven to track the maximum power by using various algorithms within distributed or centralized architectures accounting for factors such as partial irradiation and temperature changes. The effect of irradiance on the optimal panel voltage is weak or even negligible, while it is strong and quasi-linear-dependent on temperature. Based on this observation, this article introduces a straightforward method for tracking the maximum power of a PV panel by using an optimizer, focusing solely on its temperature response as an input variable. The proposed approach hinges on linearizing the relationship between panel temperature and operating voltage. This relationship enables the estimation of the maximum power point through temperature measurement alone. Thus, after determination of the linear temperature coefficient of the voltage requiring only the knowledge of two optimal voltages at different temperatures, for example from the datasheet of the panel, the power tracking involves only one temperature sensor placed on the panel alongside a voltage sensor for regulation. The principle, modelling, and validation post-panel ageing of the method are detailed in this paper. Simulation, conducted using real experimental irradiation and temperature data, attests to the effectiveness of the control. Results indicate an average effectiveness of the method of >99.1% in tracking the maximum power, with the panel generating 2.33 kWh out of a possible 2.35 kWh. This performance is comparable to that of tracking devices employing more complex algorithms. The simplicity and efficiency of the method make it a promising option for maximizing the power production at low cost from PV systems in small or residential, on- or off-grid connected applications. PubDate: Wed, 22 May 2024 00:00:00 GMT DOI: 10.1093/ce/zkae044 Issue No:Vol. 8, No. 4 (2024)
Pages: 147 - 168 Abstract: AbstractHydrogen has gained enormous relevance due to its lower carbon footprint and its potential role in balancing energy supply and demand. It is being considered as a sustainable substitute for conventional fuels. The generation of hydrogen using renewable energy sources is still in development, with a significant challenge lying in the efficient and safe storage of hydrogen due to its low energy density. This challenge hinders the widespread adoption of hydrogen. Compression and liquefaction methods of storage face issues of losses that reduce their effectiveness. The technology for hydrogen storage has advanced significantly in the past few years, driven by recent enhancements in synthesizing carbonaceous materials with hydrogen storage capabilities. This article critically reviews novel carbonaceous materials for hydrogen storage, including biochar, activated carbon, carbon nanotubes, carbon nanocomposites, carbon aerogel, fullerenes, MXenes, graphite, graphene and its derivatives. Effective hydrogen adsorption using microporous materials, such as activated carbons, is crucial, sparking interest in economically viable options for hydrogen storage. Despite this, a significant amount of work still needs to be accomplished before the potential and advantages of the hydrogen economy can be fully realized and utilized by manufacturers and academics. PubDate: Thu, 11 Jul 2024 00:00:00 GMT DOI: 10.1093/ce/zkae041 Issue No:Vol. 8, No. 4 (2024)
Pages: 169 - 182 Abstract: AbstractThe performance of photovoltaic (PV) modules is affected by environmental factors such as irradiance and temperature, which can lead to a decrease in output performance or even damage. This study proposes an improved formula for calculating the real maximum power of PV modules by analysing the influence of irradiance and temperature. A simulation model is developed using PLECS software to simulate the global maximum power of PV modules under different environmental conditions and the results are compared with the calculated real maximum power. A power optimization scheme for PV modules is then proposed based on current equalization and constant voltage control. This scheme employs a single-switch multi-winding forward–flyback converter to equalize the mismatched currents between cell strings, thereby enhancing the output performance. Traditional proportional–integral controllers are utilized to achieve constant voltage control and obtain the real maximum power of PV modules. Simulation models are built in the PLECS simulation platform to evaluate the performance of a global maximum power point tracking scheme based on the traditional perturb-and-observe (TPO) algorithm with current equalization, a segment perturb-and-observe algorithm without current equalization, and the proposed power optimization scheme. The simulation results demonstrate that the proposed constant voltage control has greater efficiency than the TPO algorithm. The proposed scheme achieves a significant improvement in efficiency, with a 27.87% increase compared with the segment perturb-and-observe algorithm without current equalization. PubDate: Thu, 11 Jul 2024 00:00:00 GMT DOI: 10.1093/ce/zkae047 Issue No:Vol. 8, No. 4 (2024)
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