Showing papers on "Renewable energy published in 2021"

Hydrogen energy systems: A critical review of technologies, applications, trends and challenges

Abstract: The global energy transition towards a carbon neutral society requires a profound transformation of electricity generation and consumption, as well as of electric power systems. Hydrogen has an important potential to accelerate the process of scaling up clean and renewable energy, however its integration in power systems remains little studied. This paper reviews the current progress and outlook of hydrogen technologies and their application in power systems for hydrogen production, re-electrification and storage. The characteristics of electrolysers and fuel cells are demonstrated with experimental data and the deployments of hydrogen for energy storage, power-to-gas, co- and tri-generation and transportation are investigated using examples from worldwide projects. The current techno-economic status of these technologies and applications is presented, in which cost, efficiency and durability are identified as the main critical aspects. This is also confirmed by the results of a statistical analysis of the literature. Finally, conclusions show that continuous efforts on performance improvements, scale ramp-up, technical prospects and political support are required to enable a cost-competitive hydrogen economy.

Wind and Solar Power Systems: Design, Analysis, and Operation

Abstract: This book provides technological and socio-economic coverage of renewable energy. It discusses wind power technologies, solar photovoltaic technologies, large-scale energy storage technologies, and ancillary power systems. In this new edition, the book addresses advancements that have been made in renewable energy: grid-connected power plants, power electronics converters, and multi-phase conversion systems. The text has been revised to include up-to-date material, statistics, and current technology trends. Three new chapters have been added to cover turbine generators, AC and DC wind systems, and recent advances solar power conversion. Discusses additional renewable energy sources, such as ocean, special turbines, etc. Covers system integration for solar and wind energy Presents emerging DC wind systems Includes coverage on turbine generators Updated sections on solar power conversion It offers students, practicing engineers, and researchers a comprehensive look at wind and solar power technologies. It is designed as a reference and can serve as a textbook for senior undergraduates in a one-semester course on renewable power or energy systems.

A study on hydrogen, the clean energy of the future: Hydrogen storage methods

Abstract: Our need for energy is constantly increasing. We consume existing oil, coal and natural gas resources in order to obtain energy. As fossil fuels are exhausted, their prices have increased and new energy sources have been sought. It is possible to meet the daily energy demand with renewable energy sources. The utilization rates of renewable energy resources are gradually increasing. The use of fossil fuels is reduced in order to reduce carbon emissions in accordance with international agreements. Therefore, the use of clean energy resources is encouraged. In this article, hydrogen energy, which is a clean energy source, has been examined. Subjects such as hydrogen sources, production, storage and transportation have been investigated from articles in the literature. The current uses of hydrogen energy, limitations in hydrogen use, future uses, future goals have been examined. In this article, studies on hydrogen energy have been gathered together and it is aimed to create a source for future articles.

Electrocatalytic Refinery for Sustainable Production of Fuels and Chemicals

Abstract: Compared to modern fossil-fuel-based refineries, the emerging electrocatalytic refinery (e-refinery) is a more sustainable and environmentally benign strategy to convert renewable feedstocks and energy sources into transportable fuels and value-added chemicals. A crucial step in conducting e-refinery processes is the development of appropriate reactions and optimal electrocatalysts for efficient cleavage and formation of chemical bonds. However, compared to well-studied primary reactions (e.g., O2 reduction, water splitting), the mechanistic aspects and materials design for emerging complex reactions are yet to be settled. To address this challenge, herein, we first present fundamentals of heterogeneous electrocatalysis and some primary reactions, and then implement these to establish the framework of e-refinery by coupling in situ generated intermediates (integrated reactions) or products (tandem reactions). We also present a set of materials design principles and strategies to efficiently manipulate the reaction intermediates and pathways.

Role of Energy Storage Systems in Energy Transition from Fossil Fuels to Renewables

Abstract: Funding information Higher Education Commission, Pakistan, Grant/Award Number: TDF02-086 Abstract We present the role of heat and electricity storage systems on the rapid rise of renewable energy resources and the steady fall of fossil fuels. The upsurge in renewable resources and slump in fossil fuel consumptions is attributed to sustainable energy systems, energy transition, climate change, and clean energy initiatives. The fast growth of renewables brings new design and operational challenges to transition towards 100% renewable energy goal. Energy storage systems can help ride-through energy transition from hydrocarbon fuels to renewable sources. Nuclear fusion and artificial photosynthesis are the ultimate Holy Grails for permanent clean energy solutions. Plants harvest light and store it in chemical energy to regulate the food supply chain that may be a guideline for an energy transition from fossil fuels to renewables. Heat and electricity storage devices can account for the periodic nature of solar and wind energy sources. Solar thermal systems for water and space heating are also a viable solution for subzero temperature areas. This study presents the transition of world's energy prospect from fossil fuels to renewables and new advances in energy storage systems.

Impact of renewable energy consumption, globalization, and technological innovation on environmental degradation in Japan: application of wavelet tools

Abstract: With regard to environmental degradation in Japan, the world's third-largest economy, limited studies have been performed to illustrate the ecological aspects of the country's core and recent economic policies such as globalization, technological innovation, and renewable energy usage policies. Given this motivation, this research reveals a new perspective on the connection between CO2 emissions and GDP growth, renewable energy, technological innovation and globalization in Japan by employing wavelet statistical tools. The paper employs series of wavelet tools for datasets covering the period from 1990Q1 to 2015Q4. The empirical outcomes demonstrate proof of the interaction between renewable energy use, economic growth, technological innovation, globalization and CO2 emissions in both time and frequency. The empirical results of the wavelet analyses reveal that globalization, GDP growth, and technological innovation increase CO2 emissions in Japan, while renewable energy usage mitigates CO2 in the short and medium terms. The results demonstrate the significance of implementing policies effectively coordinated by the policymakers to curb the significant environmental degradation in Japan. Moreover, Japan should actively support renewable energy development and create a more competitive climate for investment in the renewable energy market.

The design space for long-duration energy storage in decarbonized power systems

Abstract: Long-duration energy storage (LDES) is a potential solution to intermittency in renewable energy generation. In this study we have evaluated the role of LDES in decarbonized electricity systems and identified the cost and efficiency performance necessary for LDES to substantially reduce electricity costs and displace firm low-carbon generation. Our findings show that energy storage capacity cost and discharge efficiency are the most important performance parameters. Charge/discharge capacity cost and charge efficiency play secondary roles. Energy capacity costs must be ≤US$20 kWh–1 to reduce electricity costs by ≥10%. With current electricity demand profiles, energy capacity costs must be ≤US$1 kWh–1 to fully displace all modelled firm low-carbon generation technologies. Electrification of end uses in a northern latitude context makes full displacement of firm generation more challenging and requires performance combinations unlikely to be feasible with known LDES technologies. Finally, LDES systems with the greatest impact on electricity cost and firm generation have storage durations exceeding 100 h. Wind and solar energy must be complemented by a combination of energy storage and firm generating capacity. Here, Sepulveda et al. assess the economic value and system impact of a wide range of possible long-duration energy storage technologies, providing insights to guide innovation and policy.

Biomass-to-hydrogen: A review of main routes production, processes evaluation and techno-economical assessment

Abstract: Hydrogen is viewed as a sustainable strategic alternative to fossil fuels, especially in the field of road and air transport. Currently, hydrogen production is derived from fossil fuels or is manufactured by splitting water. A novel option, H2-generation from lignocellulosic biomass, based on renewable resources is currently in a pilot-scale demonstration or at a commercial stage. The present study reviews the thermochemical, biological, and electrochemical approaches used for biomass-to-hydrogen. The advantages, limitations, and major improvements of each process are presented. A techno-economic assessment is also established based on the production cost, technology readiness level, and industrial scalability. The objective is to allow industrial producers to visualise the degree of technological maturity of each option, clarify the necessary development efforts before reaching the commercial stage, determine the most relevant and competitive routes, and assess the suitability of biomass as a feedstock for renewable hydrogen production. In the reviewed results, the thermochemical process, particularly gasification, partial oxidation, and steam reforming, presented the best yield for H2 production. Steam gasification is the best compromise because it is suitable for wet and dry biomass, and it does not require an oxidising agent. As for biological conversion, dark fermentation is more worthwhile than photo-fermentation due to its lower energy consumption. Additionally, the electrochemical process is feasible for biomass. The findings of this study indicate that biomass-hydrogen-based processes are promising options that contribute to the H2 production capacity but require improvements to produce larger competitive volumes.

Investigate the role of technology innovation and renewable energy in reducing transport sector CO2 emission in China: A path toward sustainable development

Abstract: The objective of this research is to examine the role of economic growth, technology innovation, and renewable energy in reducing transport sector CO2 emission in China by using the annual data of 1990–2018. An application of the QARDL approach discloses that economic growth, technology innovation, and renewable energy significantly influence CO2 emission in the transportation sector in China. Both renewable energy consumption and innovation show a negative impact on emissions of CO2 related to transport. It depicts that due to the increase in renewable energy and innovation, the CO2 emission in the transport sector is likely to decrease; however, an increase in the GDP of a country will upsurge the emission of CO2 in the transportation sector. However, China should make new policies to introduce innovation in the transportation sector to minimize the emission of CO2.

Empowering smart grid: A comprehensive review of energy storage technology and application with renewable energy integration

Abstract: The rapid growth in the usage and development of renewable energy sources in the present day electrical grid mandates the exploitation of energy storage technologies to eradicate the dissimilarities of intermittent power. The energy storage technologies provide support by stabilizing the power production and energy demand. This is achieved by storing excessive or unused energy and supplying to the grid or customers whenever it is required. Further, in future electric grid, energy storage systems can be treated as the main electricity sources. Researchers and industrial experts have worked on various energy storage technologies by integrating different renewable energy resources into energy storage systems. Due to the wide range of developments in energy storage technologies, in this article, authors have considered various types of energy storage technologies, namely battery, thermochemical, thermal, pumped energy storage, compressed air, hydrogen, chemical, magnetic energy storage, and a few others. These energy storage technologies were critically reviewed; categorized and comparative studies have been performed to understand each energy storage system's features, limitations, and advantages. Further, different energy storage system frameworks have been suggested based on its application. Therefore, this paper acts as a guide to the new researchers who work in energy storage technologies. The future scope suggests that researchers shall develop innovative energy storage systems to face challenges in power system networks, to maintain reliability and power quality, as well as to meet the energy demand.