Search

For wind farms situated in resonance-prone environments, exemplified by the Xiangshan wind farm in China, where wave-induced resonance impacts most of the operating time, designing offshore wind turbines (OWT) is an urgent engineering challenge. Given the scarcity of solutions lowering resonance response while balancing power generation, this study provides a hybrid control strategy to facilitate OWT operation for optimal power capture at low wind speeds and safeguard structural integrity by mitigating fatigue loads at high speeds. This is achieved through the integration of a maximum power point tracking (MPPT) generator torque controller and a PID-based blade pitch controller, which incorporate wind speed feedforward and tower acceleration feedback. The tangible effects of hybrid control are demonstrated through the simulation of the Xiangshan wind farm employing an integral OWT model within the aero-hydro-servo-elastic-soil framework. The results show that the hybrid controller achieves a trade-off between energy capture efficiency and long-term structural stabilization. The hybrid control strategy presents effective regulation under varying environmental conditions and significantly extends the lifetime of OWT foundation while incurring minimal power production reductions. Enabling to satisfy power generation and load reduction, this research signals a promising potential for the OWT design in wave resonance-prone areas. • Dynamic responses of offshore wind turbines could be interactively influenced by wave resonance, foundation, and controller. • A hybrid controller is formulated by integrating MPPT torque control and feedback-feedforward blade pitch control. • The hybrid controller can satisfy fatigue loading mitigation and power production compensation. [ABSTRACT FROM AUTHOR]

• The world's largest Chemical Looping Combustion (CLC) demonstration unit is ready for start-up. • CLC seems to be the most cost-effective technology for power production based on solid fuels with carbon capture. • Building large units as a collaborative effort across continents is complicated, but may be both beneficial and very rewarding when all partners work closely together. The world's largest Chemical Looping Combustion (CLC) demonstration unit is being built close to the city of Chengdu in China. The design and construction of the unit, as well as the coming testing, is done within the CHEERS project, which is a collaborative project between Europe and China. The funding (∼25M€) comes from several of the project partners, in addition to EU's Horizon2020 and China's Ministry of Science and Technology (MOST). TotalEnergies has been responsible for the Front-End Engineering Design (FEED) study. The investment decision from December 2021 marks the transition from the R&D studies and design phases to Engineering, Procurement, Construction (EPC) and testing phase. The EPC phase has been led by Dongfang Boiler Co.,Ltd, and the demonstration unit is located at their technology development site in Deyang City, outside Chengdu in China. It is designed for a thermal input of 2–4 MW and includes two different reactor configurations. The first configuration is optimized for conversion of pet-coke, while the second one is tuned towards conversion of lignite. The oxygen carrier (OC) that will be used for the demonstration unit (ilmenite) will be presented, together with an overview of the various OC materials that were tested at various scales (up to 150 kWth) during the first part of the project. In addition, results from testing of a cold mock-up of the unit is presented. Finally, an overview of plans for the rest of the project is given, together with some thoughts related to intercontinental collaboration in highly collaborative projects, such as CHEERS. [ABSTRACT FROM AUTHOR]

For concentrating solar power, Brayton cycle offers a more attractive method than Rankine cycle to improve the flexibility and the efficiency of electricity production and peak-load regulation. Therefore, in this study, a solar hybrid steam-injected gas turbine system with novel heat and water recovery is proposed. The new system injects steam at the inlet of a turbine and recovers waste heat and water from exhaust gas. Thermodynamic models of the novel system are built to analyze main factors that affect the performance and characteristics. The system efficiency is improved by 17% under an optimal steam injection rate of 0.065. Water recovery rates reach up to 98%, which is associated with a high waste heat recovery rate from the exhaust gas. Compared with a single-stage absorption refrigeration unit, the heat recovery rate and refrigeration capacity of the system with a double-stage absorption refrigeration unit are increased by 109% and 63%, respectively. Furthermore, the models are applied to analyze the annual performance and environmental sustainability of the novel system in Lhasa and Dunhuang, western China. The maximum efficiency and peak power output of the novel system are increased by 21.8% and 37.9%, respectively. The consumption of fuels and emissions of CO 2 is lower than conventional gas turbine. These results indicate that the proposed system shows high efficiency possibility and environmental sustainability with a near-zero water consumption. • Water recovery rate of the proposed system could be improved to 98%. • Recovery rate of waste heat is increased by 109%. • Refrigeration capacity for precooling of inlet air is increased by 63%. • Maximum efficiency and peak power are improved by 21.8% and 37.9%, respectively. • Emissions of CO 2 are reduced by 27.5% and 24.1%, respectively. [ABSTRACT FROM AUTHOR]