The power law, a common method in wind energy assessments, often assumes a global power law exponent (alpha) of 1/7, potentially leading to inaccuracies in estimating wind conditions and energy potential. This study uses highfrequency measurements from eight wind towers to assess the power law's reliability and demonstrates its general applicability, except in complex topography. The alpha value is found to differ significantly from 1/7 in validation sites, yet it can be reliably used in ERA5 data based on regional verification. To evaluate the global spatiotemporal variation of alpha, we analyze the hourly alpha from 1980 to 2022 using ERA5 wind speed data at 10 m and 100 m. Our findings reveal varying alpha value with time and geography, with particular disparities between land and ocean. Additionally, we observe changes related to diurnal cycles, seasons, and latitudes. This analysis of alpha value carries significant implications for a global-scale wind energy resource assessment, site selection, and turbine design.

The capacity factor (CF) is a vital parameter used to quantify the performance and efficiency of a wind turbine. An increase in generation efficiency leads to higher wind power production, improving the economics within the growing global wind market. In this research, we use a data-driven statistical method to explore the contributions of the three main drivers of CF change: turbine aging, changes in wind speed, and technological improvements. We find that for the group of old turbines (operated before 2008) with an unchanging technical condition, wind increases contributed ∼10% to the increasing CF on average from 2010 to 2020. For new turbines (built from 2008 to 2020), technological improvements had a strong positive effect on CF from 2015 to 2020, exceeding the effect of wind increases and offsetting the effects of aging. On average, rising wind speeds increased CF by ∼5% per year, while technological improvements increased it by ∼12%. As the installed capacity of wind turbines grew, technological progress became the dominant driver in CF increase. However, poor site selection potentially compromised the positive effect on CF afforded by technology changes early in the decade.

Wind energy, an important component of clean energy, is highly dictated by the disposable wind speed within the working regime of wind turbines (typically between 3 and 25 m s ^−1 at the hub height). Following a continuous reduction (‘stilling’) of global annual mean surface wind speed (SWS) since the 1960s, recently, researchers have reported a ‘reversal’ since 2011. However, little attention has been paid to the evolution of the effective wind speed for wind turbines. Since wind speed at hub height increases with SWS through power law, we focus on the wind speed frequency variations at various ranges of SWS through hourly in-situ observations and quantify their contributions to the average SWS changes over 1981–2021. We found that during the stilling period (here 1981–2010), the strong SWS (⩾ 5.0 m s ^−1 , the 80th of global SWS) with decreasing frequency contributed 220.37% to the continuous weakening of mean SWS. During the reversal period of SWS (here 2011–2021), slight wind (0 m s ^−1 < SWS < 2.9 m s ^−1 ) contributed 64.07% to a strengthening of SWS. The strengthened strong wind (⩾ 5.0 m s ^−1 ) contributed 73.38% to the trend change of SWS from decrease to increase in 2010. Based on the synthetic capacity factor series calculated by considering commercial wind turbines (General Electric GE 2.5-120 model with rated power 2.5 MW) at the locations of the meteorological stations, the frequency changes resulted in a reduction of wind power energy (−10.02 TWh yr ^−1 , p < 0.001) from 1981 to 2010 and relatively weak recovery (2.67 TWh yr ^−1 , p < 0.05) during 2011–2021.

Hazardous oxyanions in water bodies are potentially toxic to aquatic life, and the coexistence of multiple anions aggravates the toxicity. Herein, bowknot-like Zr/La bimetallic organic frameworks (Zr/La-BTC) were developed with superior hazardous oxyanion adsorption capacities, i.e., approximately 102 mg/g for arsenate and 159 mg/g for phosphate, respectively. The molar ratio of Zr to La in Zr/La-BTC plays a significant role in the structure and the adsorption efficiencies. Notably, the experiment-derived adsorption capacities of various Zr/La-BTC samples were consistent with their adsorption energies calculated by density-function theory (DFT). Further mechanism analysis revealed that coordination of Zr/La atoms with the target anion groups occurred during adsorption. The positive shift of binding energies in La 3d and Zr 3d XPS spectra and Bader charge analysis unveiled that back-donation interactions dominated the adsorption process. The reliable adsorption selectivity and reusability of 0.1Zr/La-BTC were verified with anion competition experiments and four adsorption-desorption cycles. Overall, this study provides significant insight into the design of high-performance bimetallic organic frameworks for the enhanced removal of hazardous oxyanions from water.