Variation of surface solar radiation components from 2016 to 2020 in China: Perspective from geostationary satellite observation with a high spatiotemporal resolution

Solar energy scenarios in Brazil, Part one: Resource assessment

Despite South Africa’s international recognition in solar energy investments, the country is struggling to meet its growing energy needs. In recent years, national blackouts and load shedding have been a recurring experience in the country. The high cost of electrification and the overstrained national grid have left several rural communities without access to electricity. This study aims to explore the solar energy resources and performance of a 3.8 kWp stand-alone residential photovoltaic (PV) power system in one of the underutilised regions in South Africa. The study mainly uses ground measured solar radiation data to evaluate the solar resources of Alice and compare them with those in other parts of the world with mega solar PV projects. The components of solar radiation considered are global horizontal irradiance (GHI), direct normal irradiance (DNI), and diffuse horizontal irradiance (DHI). The average total daily GHI, DNI, and DHI of Alice were 4.98, 5.74, and 1.44 kWh/m2. Clear sky conditions were found to occur on 233 days in the monitoring year, resulting in an average total daily GHI of 6.13 kWh/m2, DNI of 6.73 kWh/m2 and DHI of 0.17 kWh/m2. The findings indicated that Alice possesses abundant solar resources for PV and concentrated solar power generation, and is comparable to other regions internationally.

China is rich in wind- and solar-energy resources. In recent years, under the auspices of the “double carbon target,” the government has significantly increased funding for the development of wind and solar resources. However, because wind and solar energy are intermittent and their spatial distribution is uneven, the profits obtained by the developers of wind- and solar-energy resources are unstable and relatively low. For this reason, we analyze in this article the spatiotemporal variations in wind and solar energy resources in China and the temporal complementarity of wind and solar energy by applying a Spearman correlation coefficient based on the Daily Value Dataset of China Surface Climate Data V3.0. Finally, we also strive to harmonize regions where wind and solar resources are less complementary by introducing hydro-energy resources. The results reveal that wind energy and solar energy resources in China undergo large interannual fluctuations and show significant spatial heterogeneity. At the same time, according to the complementarity of wind and solar resources, over half of China’s regions are suitable for the complementary development of resources. Further research shows that the introduction of hydro-energy resources makes it feasible to coordinate and complement the development of wind- and solar-energy resources in areas where the complementarity advantage is not significant. This has a significant effect on increasing the profit generated by the complementary development of two or more renewable resources.

To investigate the PM2.5 pollution in the southern Sichuan urban agglomeration after the implementation of China's Air Pollution Prevention and Control Action Plan (APPCAP), PM2.5 samples were simultaneously collected in four cities (Neijiang, Zigong, Yibin, and Luzhou) from November 7 to 19, 2018. The pollution characteristics of PM2.5 and main water-soluble ions were analyzed in combination with the synoptic situation, and the influence of regional transport on atmospheric pollution was also discussed in this study. The results showed that the mean ρ(PM2.5) in this region was (67.2±38.3) μg·m-3, being highest in Luzhou and lowest in Neijiang. The proportion of SNA (SO42-, NO3-, and NH4+) in PM2.5 was 33.3%, among which NO3- was dominant. From the intermediate stage (2015) to the end(2018) of the implementation of APPCAP, ρ(PM2.5) values were increased by 13.8%, 47.2%, and 69.1% in Neijiang, Yibin, and Luzhou, respectively, though unchanged in Zigong. Due to the significant reduction in ρ(SO2) but slight decrease or increase in ρ(NO2), as well as the lack of controlling NH3 emissions, from 2015 to 2018, ρ(NO3-) had increased by 36.7%-116.0%, whereas ρ(SO42-) decreased by 19.8%-40.2%, and ρ(NH4+) changed slightly in four cities. On haze days, the nitrogen oxidation rate (NOR) increased by 60.0%-118.2%, whereas the sulfur oxidation rate (SOR) increased slightly or decreased, leading to a significant increase in ρ(NO3-) (2.7-3.0 times that on clean days) and NO3-/SO42- mass ratios (1.7-1.9 on haze days). These values indicated that the secondary formation of nitrate was the dominant chemical mechanism in this haze process. On haze days, the PM2.5 pollution in this region was mainly affected by the regional transport within Sichuan Basin, particularly by the northeasterly air masses passing through Chongqing.

Health impact of China's Air Pollution Prevention and Control Action Plan: an analysis of national air quality monitoring and mortality data

Abstract. A growing body of research has demonstrated the effectiveness of China's Air Pollution Prevention and Control Action Plan in controlling PM2.5 (particulate matter with an aerodynamic diameter ≤2.5 µm), pollution. However, there is a lack of long-term studies investigating the impact of these abatement policies on carbonaceous aerosols in PM2.5, particularly secondary organic carbon (SOC). Shanghai, as China's largest megacity and a prominent industrial hub, serves as a crucial gateway to the nation's rapid development, with a population exceeding 20 million. In this study, we conducted hourly online measurements of organic carbon (OC) and elemental carbon (EC) in PM2.5 in Shanghai from July 2010 to July 2017. The results revealed that the annual concentrations (mean ± 1σ) of OC and EC reached their peaks in 2013 (9.5 ± 6.4 and 2.7 ± 2.6 to 3.0 ± 2.3 and 2.7 ± 2.1 µg m−3). Subsequently, a consistent year-to-year decrease in both OC and EC concentrations was observed, mirroring the trend observed for PM2.5. Primary organic carbon (POC), the primary component of OC, accounted for an average of 65.6 %, displaying similar trends to OC. This finding indicates the effectiveness of primary emission control measures. However, the concentration of secondary organic carbon (SOC) did not decrease from 2013 to 2017, remaining relatively stable within the range of 2.7 ± 2.6 to 3.0 ± 2.3 µg m−3. When considering data from previous studies in Shanghai, concentrations of SOC did not exhibit a noticeable decline until 2018, coinciding with the implementation of measures targeting volatile organic compound (VOC) emissions. Seasonally, with the exception of 2011, OC and EC concentrations were highest during winter, likely influenced by unfavorable meteorological conditions and long-range transport. SOC displayed no distinct seasonal fluctuations, as its formation is influenced by both photochemical reactions and meteorological conditions. POC and SOC exhibited different diurnal patterns, but neither showed a significant weekend effect, suggesting limited reduction in anthropogenic activities during weekends. Furthermore, SOC concentrations exhibited simultaneous increases in summer, particularly when O3 concentrations exceeded 50 µg m−3, indicating that stronger oxidation reactions contribute to higher SOC concentrations. Our findings also revealed concentration gradients of SOC dependent on wind direction (WD) and wind speed (WS), with higher concentrations typically observed for winds originating from the southwest and northwest. Potential sources from distant regions were analyzed using the potential source contribution function (PSCF), indicating that the geographical potential source area is concentrated near the middle and lower Yangtze River.

Revealing the impact of China's clean air policies on synergetic control of CO2 and air pollutant emissions: Evidence from Chinese cities

Air Pollution Prevention and Control Action Plan (APPCAP) is one of the most influential command-and-control environmental regulations (CMC) in China. Whether it can promote the green innovation performance of enterprises remains unclear. Based on the ‘Green Patent List’ issued by the World Intellectual Property Organization (WIPO) and the Chinese listed companies’ data, this paper applies the quasi-natural experiment methods of the difference-in-differences model and difference-in-difference-in-differences model to identify the impact of environmental regulation pressure on the green innovation of enterprises. The study finds that implementing the APPCAP promotes the enterprises’ green innovation performance in quantity and quality. Heterogeneity analysis shows that the green innovation effect of APPCAP is more obvious for those samples in the eastern region, with features of capital-intensive, labour-intensive, and low market concentration. Furthermore, our findings further support the weak version of the Porter hypothesis (PH), Whose path is that the implementation of APPCAP induces enterprises’ green innovation by promoting their innovation investment. These findings provide policy implications for the coordination of environmental regulation and green transformation in pursuit of the goal of carbon peaking and carbon neutrality goals.

Environmental regulation and labor demand: Evidence from China's air pollution prevention and Control Action Plan

China is rich in solar and wind energy resources, of which the proportion of China’s power sources has been rapidly increasing. Such fluctuating and intermittent energy sources will bring significant challenges to the safe and stable operation power system. However, making use of the spatiotemporal complementarities between different renewable energy resources is a feasible way to level fluctuating power especially when they have a widely geographical dispersion. Based on the data provided by China Meteorological Administration (CMA), this research explores the spatiotemporal complementarities between wind and solar energy resources. This paper nondimensionalizes hourly wind speed and global solar radiation data and employs several indexes to compare the smoothing effect with various combining scenarios. The results show that combining wind and solar powers within a certain area can cause a fall of zero-power or very-full power hours. Besides, combining different resources improves ‘smoothness’ in power output when compared with that from each individual resource. However, under hourly time scale, when the dispersion of sites is large enough, the smoothing effect of combining the dispersed wind power is very close to the combination of those two different resources. Nevertheless, this complementary effect is much better than that of just combining solar energy resources.

Research on solar radiation in the Mt. Everest region provides great interests for the strategies of solar energy utilization, climate change and environmental sustainability etc. We present measurement results of global horizontal irradiance, solar spectral irradiance and solar UV irradiance performed with the Dutch CMP11 Pyranometers, the German RAMSES Hyperspectral Irradiance Sensors and the Norwegian NILU-UV Irradiance Meters respectively in the Mt. Everest region during 2008 to 2017. The results show that the solar energy resources are extremely rich in that area, the daily maximum of global horizontal irradiance levels are even frequently exceed the solar constant value of 1368W/m² during monsoon season, from May to August in that region. The highest daily maximum value reached 1500 W/m² occurred on July 13, 2017. The annual average of the daily global horizontal irradiance is about 18.4 MJ/m²/d, the daily global horizontal irradiance varies from 13.8 to 23.9 MJ/m²/d, indicates that there are abundant solar energy in that alpine zone. The instruments record that even during the winter time (October to January) more than 15 days of each month are absolute clear days, it shows 28 clear days in November of 2016. It points out that more solar energy can be existed during the winter time due to dry season. The solar spectral irradiance was performed for the first time in this special environment presenting the characteristics of solar spectrum over the region. It reveals not only how abundant the spectral irradiance is, but also rich information about the atmospheric composition over the sky. It is well known that the solar UV radiation strongly impacts on the ecological environment and human health. The measurement results of solar UV dose rates as well as their impact factors (ozone and cloud) during the period of 2008 to 2017 are also presented. Satellite data are also used to see how the solar irradiance is distributed over the Himalayan region in summer, including Mt. Everest.

Based on the multi-model ensemble average results of the CMIP5 program, we predict the changes of global terrestrial wind and solar energy resources from 2020 to 2030 under different future climate change scenarios. The results show that the multi-mode ensemble average results have high confidence in the simulation of global wind and solar energy resources. Under different climate scenarios (RCPs), the changes in global terrestrial wind and solar energy resources in the next 2020-2030 (relative to 1986-2005) will have significant regional differences. Among them, wind resources in the Americas, Africa and Australia increased, while European wind-rich areas decreased; those in Asia (e.g., Northwest China and Central Asia) increased in RCP2.6, but decreased in RCP4.5 and RCP8.5. Global terrestrial solar energy resources are increasing in different RCPs scenarios in the future, especially in European solar energy-rich areas. Wind energy and solar energy resources on the global land have obvious seasonal variation characteristics, and the seasonal variation rate varies greatly in different regions. The change trend and change range of wind energy and solar energy resources in different rich areas are different. There are some differences in the RCPs scenario. It shows the complexity of future changes in wind and solar energy resources in response to global climate change.

This paper presents a study of the complementarity of wind and solar resources over Mexico for electricity generation. A dataset was generated using high-resolution wind and solar resource maps provided by the SIGER project to assess the possibility of a combined used of these renewable energy sources. Using image processing techniques, the values of average monthly wind speed and solar irradiation were obtained, and then the average energy production was calculated. In order to obtain new maps that show the degree of correlation between the wind and solar resources the Pearson correlation coefficient was applied. The obtained results show a good degree of complementarity between both energy sources, in specific places of the country in the different seasons of the year. The obtained maps can be useful in projects related to the installation of hybrid renewable energy generation systems that have wind turbines and photovoltaic cells.

Multi-Combination Method for Intelligent Remote Sensing of Solar Energy Resources in Different Regions

Do policies make a difference? Assessing the impact of China's air pollution prevention and control action plan on carbon emissions