Hasil untuk "Renewable energy sources"

Mohammad Dreidy, H. Mokhlis, S. Mekhilef

Erdiwansyah, Mahidin, H. Husin et al.

Wind power, solar power and water power are technologies that can be used as the main sources of renewable energy so that the target of decarbonisation in the energy sector can be achieved. However, when compared with conventional power plants, they have a significant difference. The share of renewable energy has made a difference and posed various challenges, especially in the power generation system. The reliability of the power system can achieve the decarbonization target but this objective often collides with several challenges and failures, such that they make achievement of the target very vulnerable, Even so, the challenges and technological solutions are still very rarely discussed in the literature. This study carried out specific investigations on various technological solutions and challenges, especially in the power system domain. The results of the review of the solution matrix and the interrelated technological challenges are the most important parts to be developed in the future. Developing a matrix with various renewable technology solutions can help solve RE challenges. The potential of the developed technological solutions is expected to be able to help and prioritize them especially cost-effective energy. In addition, technology solutions that are identified in groups can help reduce certain challenges. The categories developed in this study are used to assist in determining the specific needs and increasing transparency of the renewable energy integration process in the future.

Ana Fernández-Guillamón, E. Gómez-Lázaro, E. Muljadi et al.

Abstract Traditionally, inertia in power systems has been determined by considering all the rotating masses directly connected to the grid. During the last decade, the integration of renewable energy sources, mainly photovoltaic installations and wind power plants, has led to a significant dynamic characteristic change in power systems. This change is mainly due to the fact that most renewables have power electronics at the grid interface. The overall impact on stability and reliability analysis of power systems is very significant. The power systems become more dynamic and require a new set of strategies modifying traditional generation control algorithms. Indeed, renewable generation units are decoupled from the grid by electronic converters, decreasing the overall inertia of the grid. ‘Hidden inertia’, ‘synthetic inertia’ or ‘virtual inertia’ are terms currently used to represent artificial inertia created by converter control of the renewable sources. Alternative spinning reserves are then needed in the new power system with high penetration renewables, where the lack of rotating masses directly connected to the grid must be emulated to maintain an acceptable power system reliability. This paper reviews the inertia concept in terms of values and their evolution in the last decades, as well as the damping factor values. A comparison of the rotational grid inertia for traditional and current averaged generation mix scenarios is also carried out. In addition, an extensive discussion on wind and photovoltaic power plants and their contributions to inertia in terms of frequency control strategies is included in the paper.

Hsing-Chen Lee, Ching-Ter Chang

Multi-criteria decision making (MCDM) methods are becoming increasingly popular in solving energy selection problems because these problems involve multiple and often conflicting criteria. This paper presents comparative analysis of ranking renewable energy sources (RES) for electricity generation in Taiwan using four MCDM methods - WSM, VIKOR, TOPSIS, and ELECTRE. The Shannon entropy weight method is used to assess the importance of each criterion for the ranking of RES. After that, four MCDM methods are utilized for quantitative evaluation to rank all available RE alternatives. From the weights estimation results, efficiency is the first priority in all evaluation criteria, followed by job creation, operation, and maintenance cost. The purpose of this study is to rank the priorities of various RES and propose recommendations for Taiwan's RE development. The ranking results show that hydro is the best alternative in Taiwan, followed by solar, wind, biomass and geothermal. Furthermore, sensitivity analysis of the weights was conducted considering the ranking results heavily depend on the criteria weight. The results of sensitivity analysis indicated that when financial or technical aspects are focused upon, hydropower is the best RES because its technology is the most mature and the cost is the lowest in Taiwan. In addition, from an environmental perspective, wind energy is the best choice, and from the social perspective, solar PV is the best choice. The findings of this study can provide useful information to energy decision makers and serve as a reference for Taiwan's energy policy.

A. Al‐Shetwi, M. Hannan, K. P. Jern et al.

Abstract The growing of renewable power generation and integration into the utility grid has started to touch on the security and stability of the power system operation. Hence, the grid integration requirements have become the major concern as renewable energy sources (RESs) such as wind and solar photovoltaic (PV) started to replace the conventional power plant slowly. In line with this, some of the new requirements and technical regulations have been established to ensure grid stability. This study aims to fill the gap and conduct an updating review of the recent integration requirements and compliance control methods regarding the penetration of renewable power plants to the power grid. The review is conducted by a comparing of the key requirements related to voltage stability, frequency stability, voltage ride-through (VRT), power quality, active and reactive power regulations towards grid stability. In order to fulfill these requirements, different control methods have been recently proposed. Accordingly, this paper compares and reviews the state-of-the-art solutions for compliance technology and control methods. Furthermore, a broad discussion on the global harmonization of the integration requirements, challenges, advantages and disadvantages is also highlighted. The rigorous review indicates that although the recent integration requirements can improve the grid operation, stability, security, and reliability, further improvements are still required with respect to protective regulations, global harmonization, and control optimization. Various recommendations for future research related to the integration and technical regulations of RESs are then presented. In sum, the insights provided by this review may aid the development of smooth and stable grid integration of RESs, help developers and researchers to develop the design and control strategies in the sense of current requirements. Additionally, assist power system operators in establishing or improving their own requirements in comparison with the remaining international requirements.

A. Abdalla, M. S. Nazir, Hai Tao et al.

Abstract Energy storage technology plays a role in improving new energy consumption capacities, ensuring the stable and economic operation of power systems, and promoting the widespread application of renewable energy technologies. Several new developments, ideas, approaches, and technologies have been introduced into this area from fields including materials, knowledge manage, electricity, control, and artificial intelligence. Based on the technical characteristics of renewable energy, this study reviews the roles, classifications, design optimisation methods, and applications of energy storage systems in power systems. First, we introduce the different types of energy storage technologies and applications, e.g. for utility-based power generation, transportation, heating, and cooling. Second, we briefly introduce the states of an energy storage system, along with its operation processes and energy storage capacity. Third, a comprehensive review is conducted on artificial intelligence applications in regards to optimisation system configuration, and energy control strategy, along with the applicability of different energy storage technologies. Finally, several issues and insights are discussed, offering new inspiration and concepts for the future study of integrated energy storage systems.

Md. Shafiul Alam, Fahad Alismail, A. Salem et al.

The utilization of renewable energy sources (RESs) has become significant throughout the world, especially over the last two decades. Although high-level RESs penetration reduces negative environmental impact compared to conventional fossil fuel-based energy generation, control issues become more complex as the system inertia is significantly decreased due to the absence of conventional synchronous generators. Some other technical issues, high uncertainties, low fault ride through capability, high fault current, low generation reserve, and low power quality, arise due to RESs integration. Renewable energy like solar and wind are highly uncertain due to the intermittent nature of wind and sunlight. Cutting edge technologies including different control strategies, optimization techniques, energy storage devices, and fault current limiters are employed to handle those issues. This paper summarizes several challenges in the integration process of high-level RESs to the existing grid. The respective solutions to each challenge are presented and discussed. A comprehensive list of challenges and solutions, for both wind and solar energy integration cases, are well documented. Finally, the future recommendations are provided to solve the several problems of renewable energy integration which could be key research areas for the industry personnel and researchers.

G. Halkos, Eleni-Christina Gkampoura

The world’s ever-increasing population, combined with economic and technological growth and a new, modern way of life, has led to high energy demand and consumption. Fossil fuels have been the main energy source for many years, but their use has many negative impacts on the environment. This has made the transition to renewable energy sources necessary in order to address climate change and meet the 1.5 °C goal. This paper is a review of the different types of renewables, their potentials and limitations, and their connection to climate change, economic growth, and human health. It also examines consumers’ willingness to pay for renewables in different countries, based on the existing literature. IEA (International Energy Agency) data are analyzed, concerning renewables’ current use, the evolution of their usage, and forecasts about their future usage. Finally, policies and strategies are recommended in order to address climate change and fully integrate renewables as a sustainable energy source.

Saumajit Saha, M. Saleem, T. K. Roy

Dario Maradin

Renewable energy sources are still not the predominant energy resource in the energy sector, although in certain developed countries they participate in a significant share in electricity generation. It is estimated that world energy consumption from renewable energy sources exceeds 20% at the present and continues to grow. Renewable energy sources appear as an additional source of energy in the conventional electro-industry. The main reason for the increasing investment and exploitation of renewables is certainly environment preservation and environmental aspect of sustainability. This study seeks to expand the existing literature and contribute to a comprehensive understanding of the characteristics of renewable energy sources as a whole. Therefore, the purpose of this paper is to determine the advantages and disadvantages of renewable energy sources utilization in general, without considering the individual type of renewables, such as wind or solar energy. Thereby, the paper presents numerous advantages of using renewable energy in the electricity generation, such as environment preservation in terms of reduced greenhouse gas emissions or improvement of innovations and technical/technological development. There are also presented certain disadvantages of renewables in the production of electricity, such as dependence on weather conditions or low energy efficiency and low ability to produce electricity.

Argyris Panagopoulos

Ruifeng Shi, Shaopeng Li, Penghui Zhang et al.

The electric vehicle to grid (V2G) interaction technology can improve the utilization of renewable energy and stabilize its grid connection. At the same time, renewable energy can be used for a microgrid nearby, or incorporated into a large grid, to effectively address the volatility of renewable energy sources. Motivated by the increasing number of electric vehicles (EVs) and the randomness of renewable energy output, this paper proposes an effective strategy to improve the security and economy of the microgrid system. The uncertainty of wind power and EV’s state of charge (SOC) is modeled as uncertainty prediction sets. And considering the worst-case scenario, this proposed strategy can increase the absorption ratio of renewable energy while orderly guiding the charging and discharging of EVs in peak-load reduction and valley filling and thus, lower operating costs under various practical constraints. To solve the problem of over-conservatism of the robust optimization, this paper introduces a dispatch interval coefficient to adjust the degree of conservatism, while improving the economy of microgrids system. The robustness and feasibility of the proposed dispatch strategy are demonstrated by numerical case studies.

Wei-Jen Liu, Wei-Yu Chiu, Weiqi Hua

In the 21st century, transitioning to renewable energy sources is imperative, with fossil fuel reserves depleting rapidly and recognizing critical environmental issues such as climate change, air pollution, water pollution, and habitat destruction. Embracing renewable energy is not only an environmental necessity but also a strategic move with multiple benefits. By shifting to renewable energy sources and supporting their production through the acquisition of renewable energy certificates, we foster innovation and drive economic growth in the renewable energy sector. This, in turn, reduces greenhouse gas emissions, aligning with global efforts to mitigate climate change. Additionally, renewable energy certificates ensure compliance with regulations that mandate the use of renewable energy, enhancing legal adherence while promoting transparency and trust in energy sourcing. To monitor the uptake of renewable energy, governments have implemented Renewable Energy Certificates (RECs) as a tracking mechanism for the production and consumption of renewable energy. However, there are two main challenges to the existing REC schema: 1) The RECs have not been globally adopted due to inconsistent design; 2) The consumer privacy has not been well incorporated in the design of blockchain. In this study, we investigate the trading of RECs between suppliers and consumers using the directed acyclic graph (DAG) blockchain system and introduce a trading schema to help protect consumer information. Our results demonstrate lower transaction time by 41\% and energy consumption by 65\% compared to proof-of-stake.

Taiyo Mantani, Hikaru Hoshino, Tomonari Kanazawa et al.

This paper proposes a novel computationally efficient algorithm for optimal sizing of Battery Energy Storage Systems (BESS) considering renewable energy bidding strategies. Unlike existing two-stage methods, our algorithm enables the cooptimization of both by updating the BESS size during the training of the bidding policy, leveraging an extended reinforcement learning (RL) framework inspired by advancements in embodied cognition. By integrating the Deep Recurrent Q-Network (DRQN) with a distributed RL framework, the proposed algorithm effectively manages uncertainties in renewable generation and market prices while enabling parallel computation for efficiently handling long-term data.

Christian Truitt Lüddeke, Birger Hagemann, Leonhard Ganzer

The energy transition is a long-term strategy dedicated to achieving carbon neutrality in Germany by 2045. This process includes the development of renewably generated electricity from wind and solar power. As these energy sources are dependent on weather conditions, imbalances in availability and demand might result in a deficit or excess of renewable energy. In times of excessive availability, hydrogen can be generated and stored in subsurface storage sites from which it can be withdrawn when the demand increases. Using subsurface storage sites is a viable option as those currently store natural gas. Considering the properties of hydrogen, converting existing storage sites poses many challenges, including the total stored energy content and the amount of extractable working gas. Using an exemplary storage formation, a numerical simulation model is set up in an open-source software and used to calculate and compare the stored volumes and energy contents for natural gas and hydrogen. Storage withdrawal and pressure profiles for both cases are developed. A pseudo gas is defined with individually alternating compressibility, density and viscosity behavior to independently assess the influence of these properties on the withdrawal rates. A sensitivity analysis of various storage, bottom-hole flowing pressures and the skin factor on the extraction rates is also performed. The results show that a larger volume of natural gas and a resulting higher energy content can be stored in the storage site compared to hydrogen. Changes in extraction rates occur earlier and pressure decrease is greater for stored hydrogen. The compressibility factor has the largest influence on the extraction behavior of the gas, leading to a steeper decline in hydrogen withdrawal rates and a quicker pressure depletion. The levels of the storage and the bottom-hole flowing pressure impact the slope of the decline and the level of withdrawal rates.

Pál Boza, T. Evgeniou

Abstract The power sector is increasingly relying on variable renewable energy sources (VRE) whose share in energy production is expected to further increase. A key challenge for adopting these energy sources is their high integration costs. Artificial intelligence (AI) solutions and data-intensive technologies are already used in different parts of the electricity value chain and, due to the growing complexity and data generation potential of the future smart grid, have the potential to create significant value in the system. However, different uncertainties or lack of understanding about its impact often hinder the commitment of decision makers to invest in AI and data intensive technologies, also in the energy sector. While previous work has outlined a number of ways AI solutions can be used in the power sector, the goal of this article is to consider the value creation potential of AI in terms of managing VRE integration costs. We use an economic model of variable renewable integration cost from the literature to present a systematic review of how AI can decrease substantial integration costs. We review a number of use cases and discuss challenges estimating the value creation of AI solutions in the power sector.

N. Tomin, V. Shakirov, A. Kozlov et al.

U. Ahmad, M. Usman, S. Hussain et al.

Victor Dachet, Antoine Dubois, Bardhyl Miftari et al.

Serving the energy demand with renewable energy is hindered by its limited availability near load centres (i.e. places where the energy demand is high). To address this challenge, the concept of Remote Renewable Energy Hubs (RREH) emerges as a promising solution. RREHs are energy hubs located in areas with abundant renewable energy sources, such as sun in the Sahara Desert or wind in Greenland. In these hubs, renewable energy sources are used to synthetise energy molecules. To produce specific energy molecules, a tailored hub configuration must be designed, which means choosing a set of technologies that are interacting with each other as well as defining how they are integrated in their local environment. The plurality of technologies that may be employed in RREHs results in a large diversity of hubs. In order to characterize this diversity, we propose in this paper a taxonomy for accurately defining these hubs. This taxonomy allows to better describe and compare designs of hubs as well as to identify new ones. Thus, it may guide policymakers and engineers in hub design, contributing to cost efficiency and/or improving local integration.

E. Blanc‐Betes, N. Gomez‐Casanovas, C. J. Bernacchi et al.

ABSTRACT The expansion of sugarcane onto land currently occupied by improved (IMP) and semi‐native (SN) pastures will reshape the U.S. bioenergy landscape. We combined biometric, ground‐based and eddy covariance methods to investigate the impact of sugarcane expansion across subtropical Florida on the carbon (C) budget over a 3‐year rotation. With 2.3‐ and 5.1‐fold increase in productivity over IMP and SN pastures, sugarcane displayed a C use efficiency (CUE; i.e., fraction of gross C uptake allocated to plant growth) of 0.59, well above that of pastures (0.31–0.23). Sugarcane also had greater C allocation to aboveground productivity and hence, harvestable biomass relative to IMP and SN. Cane heterotrophic respiration over the 3‐year rotation (903 ± 335 gC m−2 year−1) was 1% and 14% higher than IMP and SN pastures, respectively. These soil C losses responded largely to disturbance over the first year after conversion (1510 ± 227 gC m−2 year−1) but declined in subsequent years to an average 599 ± 90 gC m−2 year−1—well below those of IMP (933 ± 140 gC m−2 year−1) and SN (759 ± 114 gC m−2 year−1) pastures—despite a significant 40%–61% increase in soil C inputs. Soil C inputs, however, shifted from root‐dominated in pastures to litter‐dominated in sugarcane, with only 5% C allocation to roots. Reduced decomposition rates in sugarcane were likely driven by changes in the recalcitrance and distribution rather than the size of the newly incorporated soil C pool. As a result, we observed a rapid shift in the net ecosystem C balance (NECB) of sugarcane from a large source immediately following conversion to approaching the net C losses of IMP pastures only 2 years after conversion. The environmental cost of converting pasture to sugarcane underscores the importance of implementing management practices to harness the soil C storage potential of sugarcane in advancing a sustainable bioeconomy in Southeastern United States.