A blackout is usually the result of load increasing beyond the transmission capacity of the power system. A collapsing system enters a contingency state before the blackout. This contingency state is characterized by a decline in the bus voltage magnitudes. To avoid blackouts, power systems may start shedding load when a contingency state occurs called under voltage load shedding (UVLS). The success of a UVLS scheme in arresting the contingency state depends on shedding the optimum amount of load at the optimum time and location. This paper proposes a hybrid algorithm based on genetic algorithms (GA) and particle swarm optimization (PSO). The proposed algorithm can be used to find the optimal amount of load shed for systems under stress (overloaded) in smart grids. The proposed algorithm uses the fast voltage stability index (FVSI) to determine the weak buses in the system and then calculates the optimal amount of load shed to recover a collapsing system. The performance analysis shows that the proposed algorithm can improve the voltage profile by 0.022 per units with up to 75% less load shedding and a convergence time that is 53% faster than GA.

China intends to develop its renewable energy sector in order to cut down on its pollution levels. Concentrated solar power (CSP) technologies are expected to play a key role in this agenda. This study evaluated the technical and economic performance of a 100 MW solar tower CSP in Tibet, China, under different heat transfer fluids (HTF), i.e., Salt (60% NaNO₃ 40% KNO₃) or HTF A, and Salt (46.5% LiF 11.5% NaF 42% KF) or HTF B under two different power cycles, namely supercritical CO₂ and Rankine. Results from the study suggest that the Rankine power cycle with HTF A and B recorded capacity factors (CF) of 39% and 40.3%, respectively. The sCO₂ power cycle also recorded CFs of 41% and 39.4% for HTF A and HTF B, respectively. A total of 359 GWh of energy was generated by the sCO₂ system with HTF B, whereas the sCO₂ system with HTF A generated a total of 345 GWh in the first year. The Rankine system with HTF A generated a total of 341 GWh, while the system with B as its HTF produced a total of 353 GWh of electricity in year one. Electricity to grid mainly occurred between 10:00 a.m. to 8:00 p.m. throughout the year. According to the results, the highest levelized cost of energy (LCOE) (real) of 0.1668 USD/kWh was recorded under the Rankine cycle with HTF A. The lowest LCOE (real) of 0.1586 USD/kWh was obtained under the sCO₂ cycle with HTF B. In general, all scenarios were economically viable at the study area; however, the sCO₂ proved to be more economically feasible according to the simulated results.

The development of a heterogeneous Fenton-like catalyst, possessing a high degradation efficiency in a wide pH range, is crucial for wastewater treatment. An Fe–Mn–SiO₂ catalyst was designed and prepared by a hydrothermal method. Density functional theory (DFT) calculations demonstrated that the dual reaction centers were produced around the Fe and Mn atoms, due to valence-electron density distribution. The Fe–Mn–SiO₂ catalyst with dual reaction centers was applied for sulfamethazine (SMT) degradation in the Fenton-like process at a pH value of 4.0–8.6. Almost 100% SMT degradation efficiency was achieved under neutral pH at room temperature within 180 min. Moreover, the Fe–Mn–SiO₂/H₂O₂ system showed a high degradation efficiency (60–100%) for removing a wide range of aromatic pollutants, including bisphenol A, phenol, 4-chlorophenol, phenytoin, and ibuprofen. Besides, this process showed strong resistance to interference of inorganic anions (Cl⁻, SO₄ ²⁻, NO₃ ⁻ and HCO₃ ⁻). Electron paramagnetic resonance and radical scavenger experiments confirmed that the generated ¹O₂ and O₂˙⁻/HO₂˙ played an important role in the degradation of organic pollutants. In the Fe–Mn–SiO₂/H₂O₂ system, the electron-rich center around Fe was responsible for the reduction of H₂O₂ to ¹O₂, O₂˙⁻/HO₂˙ and ˙OH radicals, and then the electron-poor center around Mn adsorbed pollutants and transferred electrons to the electron-rich center around Fe via the Fe–O–Mn bridge.