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Abstract The main aim of this study was to analyse scientific and energy production, funding, collaboration among countries and most cited papers on the renewable energies topic through bibliometric and social network study of articles included in the Web of Science database. 12,167 papers were recovered from 2007 to 2016. Wind power is the energy from which a greater number of articles have been published (n = 3,930), followed by solar energy (n = 2,570) and ocean energy (n = 1,565). The United States leads the world production of articles (n = 2,320), followed by China (n = 1,629), the United Kingdom (n = 1007), Germany (n = 730) and Spain (n = 729). China is the leading country in financed works (80%), followed by South Korea (77%), Spain (61%) and the United States (59%). An important level of international collaboration has been identified, notably popping up the triangle made by United States, China and the European Union. Highlights • Scientific study based in the analysis of the energy production, funding and collaboration among countries. • Wind power is the energy from which a greater number of articles have been published. • The United States leads the world production of articles. • China is the leading country in financed works. • The triangle made by United States, China and the European Union have the most important level of collaboration. [ABSTRACT FROM AUTHOR]

Renewable portfolio standard is an effective administrative tool to guide the behavior of electricity producers and impact the renewable energy diffusion. However, currently the renewable energy quota is generally set to be static and the efficiency is limited. In this paper, we proposed a dynamic renewable portfolio standard policy and we aimed to analyze how it will impact the renewable energy diffusion in China. The connections between electricity producers were simulated under both the perfectly competitive market and monopoly market. And a networked evolutionary game approach is applied considering dynamic linking between the electricity producers. The results show that dynamic quota policy is effective in promoting the proportion of wind power generation from 20% to 59.17% and promoting the proportion of solar power generation from 20% to 79.25%. With the sensitivity analysis, we found that renewable energy quota and the on-grid price are the most influential parameters. The proportion will reach 76.47% if quota is 0.7 and 68.1% if on-grid price is 630 Yuan/MWh. And the influence of tradable green certificate prices and generation cost is limited in promoting renewable energy diffusion. This paper offers the Chinese government a potential implementation for the perfection of national renewable energy diffusion. [Display omitted] • Propose a novel dynamic renewable portfolio standard scheme. • Analyze the influences of different kinds of the electricity market. • Investigate parameters affecting the wind power and solar power generation. • Establish dynamic networked evolutionary game models. • Dynamic linking is considered when the connections of players change. [ABSTRACT FROM AUTHOR]

Distributed energy systems are becoming increasingly popular worldwide. The 100% renewable energy system can be an important energy supply alternative to reduce the carbon emissions and address energy shortage, especially for remote areas. However, the performance of 100% renewable energy system (RES) at community level needs further detailed analysis, which is affected by the climates, availability of renewable energy and local energy markets. This paper proposes a design optimization framework of 100% renewable energy systems for low-density communities and investigates the system performance. To investigate the integration and performance of 100% RES, thirty typical cities located in different regions of China were chosen considering different climates, geographical features, and renewable energy distributions. By taking the economic performance as the optimization objective, the optimal design for the 100% RES is obtained, and the energy and economic performance is analyzed. Results show that, under the current energy market conditions, the 100% RES is feasible for low-density communities in most regions of China. The payback periods of the systems in most cities are less than six years. When the cost of PV is reduced by half considering future technological developments, the payback period of a 100% RES can be reduced by 30%–60%. This paper would provide design suggestions and application recommendations in regard to promoting 100% RES in China. • Application of 100% renewable energy system at community level is studied. • 30 zones are selected considering climates, renewable energy sources and markets. • Solar energy and biomass can contribute to over 90% of the total energy supply. • Investment of 100% RES can be paid back in 6 years for most regions. • Payback periods can be reduced by 30%–60% when PV technology is further developed. [ABSTRACT FROM AUTHOR]

The world's key renewable power markets are generally challenged by wind and solar power curtailment. Research on the influencing factors of curtailment improvement can provide a reference for the further penetration of renewable energy (RE) into the power system. Based on the logarithmic mean Divisia index (LMDI) method, this paper analyzes the factors influencing the wind and solar power consumption rate in China from 2015 to 2018, and four typical provinces are discussed in detail. By decomposing the consumption rate into six factors (transmission structure, generation proportion, power self-sufficiency, resource development, resource utilization, and power consumption), and focusing on the transmission structure factors, this paper further clarifies the contributions of local use, ultra-high-voltage (UHV) transmission, and conventional transmission to the improvement of curtailment. The results reveal the following. (1) At the national level, the power mixing effect and the resource development effect have played major roles in the change of the consumption rate, but the influences of these two effects have been decreasing. (2) The UHV power lines provide a robust resource for the inter-provincial deployment of renewable power (such as the RE power transfer in Inner Mongolia and Gansu), but the role of UHV transmission has not yet been fully utilized. (3) The impact of the electricity consumption effect on renewable power consumption is increasing year by year, but the local consumption capacity remains insufficient (both at the national level and in the four typical provinces analyzed), so it is necessary to further increase the share of renewable electricity in UHV power transmission and the local consumption capacity. (4) The expanding development of wind and solar power may be the reason for the curtailment in Shaanxi, and a reasonable renewable power development plan must be further formulated. [ABSTRACT FROM AUTHOR]

Accurate and credible operation data sets of wind and solar power stations are the basis of many research works. However, such data sets often contain abnormal data due to failure, maintenance, energy curtailment, etc. The existing identification methods fail to consider the operating characteristics of power stations and the forms of abnormal data, resulting in low identification ability. Therefore, an adaptive identification method of abnormal data (AIMAD) in the wind and solar power stations is proposed in this paper, including the bidirectional one-sided quartile method and double DBSCAN method to deal with unevenly distributed abnormal data; the improved K-means clustering method based on the distance between the cluster center and benchmark power curve to process the abnormal data that are densely accumulated and closely connected with normal data in the power scatter diagram. The proposed method can adjust adaptively according to the forms of abnormal data to realize accurate identification and has strong robustness for power stations. The operation data of 30 wind farms and 8 solar plants in China are taken as examples to verify the effectiveness and superiority of the proposed method. • BOQ and d-DBSCAN are proposed to deal with unevenly distributed abnormal data. • Improved K-means method is proposed for identifying stacked abnormal data. • AIMAD is proposed to realize accurate identification of abnormal data. • Operation data in 38 stations are used to verify the effectiveness of AIMAD. [ABSTRACT FROM AUTHOR]

Poverty alleviation is an important work of the Chinese government in recent years. According to the international poverty standards of the world bank, China's poverty reduction population accounts for more than 70% of the world. Photovoltaic poverty alleviation is a significant way for regions rich in solar energy resources to transform the advantages of renewable energy resources into the driving force of social and economic development. It is also an effective means for China to implement power poverty alleviation. While promoting emission reduction in these regions, it accelerates economic development and implements targeted poverty alleviation. This paper analyzes the comprehensive benefits of typical market entities of photovoltaic poverty alleviation projects, and establishes the environment, economic and social benefit evaluation models for poor households, the state and government, photovoltaic enterprises and grid corporation. In the model, we creatively put forward an index system to characterize the poverty alleviation effect, and consider the additional industrial benefits brought by photovoltaic poverty alleviation projects. Finally, a typical photovoltaic poverty alleviation project in Haiyuan County, Northwest China is selected to verify the feasibility of this model. [ABSTRACT FROM AUTHOR]

Despite the considerable contribution of hydropower for meeting electricity demand and meanwhile achieving free carbon emission, the rationality of hydropower exploitation needs to be reassessed in the context of hydropower curtailment being severe in some hydro-dominant areas. In this paper, a two-stage fuzzy-stochastic chance-constrained interval (TFCI) regional energy system optimization model under multiple complexities is developed for systematically assessing the rationality of existing hydropower exploitation plan, and reflecting the tradeoff between system cost and reliability for Sichuan territory where the exploitable hydropower resources rank first in China. Results showed that the degree of hydropower overcapacity would become far more severe under the real existing energy structure planning. Instead of continuously boosting hydropower exploitation, proper limitation on hydropower installed capacity expansion to make other renewable energy obtain deserved promotion can effectively reduce system cost and improve the utilization efficiency of all the renewable technologies. The highest utilization efficiency of hydropower, wind power and solar power could achieve [90%, 100%], [100%, 100%], and [100%, 100%], respectively. The obtained results also indicated that greater uncertainty about system cost may have to be faced if policymakers aim to lower risk and enhance system reliability. Suggestions are provided for eliminating the irrationality of hydropower in Sichuan and other similar hydro-dominant regions based on above mentioned conclusions. • Developing a TFCI model for the rationality of renewable energy development. • Evaluating Sichuan's hydropower exploitation from a comprehensive view. • Investigating far more severe hydropower curtailment under existing energy policy. • Suggesting proper limitation on hydropower exploitation. [ABSTRACT FROM AUTHOR]

The increasing generation of renewable energy and its concurrent technological innovation are driving the transformations of the energy sector, but little effort has been made at the regional level to specify the heterogeneous impacts of different types of renewable energy development on multi-dimensional energy security. Therefore, this paper establishes a four-dimensional energy security assessment system based on the current energy market situation and economic context of China. Renewable energy generation and technological innovation were simultaneously used as the core proxies for renewable energy development. Then, the panel quantile regression method was used to analyze the heterogeneity of the impact of solar, hydro, and wind energy on energy security, covering 30 provinces in China from 2006 to 2019. The empirical results show that renewable energy power generation generally promotes energy security, but it cannot be effectively applicable to all levels of energy security. Renewable energy technology innovation has surprisingly hindered energy security. These results can serve as a policy and practical guide, suggesting that provincial governments in China should implement energy security and renewable energy policies in line with local characteristics. • The redefined provincial energy security presents obvious spatial heterogeneity. • Panel quantile regression was applied to balanced provincial panel data. • Hydropower contributes only to medium and low levels of energy security. • Wind and solar power contribute differently to all levels of energy security. • Renewable energy technological innovation impedes energy security. [ABSTRACT FROM AUTHOR]

China, India, and the USA are the world's biggest energy consumers and CO 2 emitters. Being the leading contributors to climate change, these economies are also at the core of environmental solutions. This paper investigates the causal relationship among solar and wind energy production, coal consumption, economic growth, and CO 2 emissions for these three countries. To do so, we use an advanced methodology in Machine Learning to verify the predictive causal linkages among variables. The Causal Direction from Dependency (D2C) algorithm set CO 2 emissions as the target variable. The obtained results were disaggregated and estimated in a supervised prediction model. The findings, confirmed by three different Machine Learning procedures, showed an interesting output. While a reduction in overall carbon emissions is predicted in China and the US (resulting from the intensive use of renewable sources of energy), India displays critical predictions of a rise in CO 2 emissions. This indicates that curbing CO 2 emissions cannot be achieved without conducting a comprehensive shift from fossil to renewable resources, although China and the U.S. present a more promising path to sustainability than India. Being an emerging renewable energy leader, India should further enhance the use of low-carbon sources in its power supply and limit its dependence on coal. • Renewable energies, coal consumption, economic growth, and CO 2 we examine. • We investigate the causal predicted relationship on China, India, and the USA. • An advanced methodology in Machine Learning is used. • India has a prediction of an increase in emissions of CO 2. • China and the U.S. present a more promising path to sustainability than India. [ABSTRACT FROM AUTHOR]

Contagion tests through mean and volatility channels are developed based on an exponential generalized autoregressive conditional heteroskedastic model to investigate the effects of China's 2009–2020 solar power policies on the economic performance of different sectors. By examining the fluctuations in the daily stock prices of nine major economic sectors in China, we show the transmission mechanisms of policy shocks and find evidence that China's major solar energy policies, including feed-in tariffs, solar subsidies, and market-based instruments, have significant effects on most of the studied sectors in China through both mean and volatility contagion channels. Among the three types of policies, feed-in tariffs and solar subsidies are found to be the most effective instruments in improving sector performance, while market-based instruments have the least effect. The risk premium effect is weak, but the asymmetric effect is strong, suggesting that market volatility responds considerably less to positive news than to negative news for the majority of sectors investigated. • The highlights of this paper include. • The impacts of China's 2009–2020 solar industry policies on its sector performance. • Policy contagion is developed to identify how policy shocks affect economic sectors. • Feed-in tariffs and solar subsidies are found to be effective instrument. • Significant asymmetric effect is observed in major economic sectors. [ABSTRACT FROM AUTHOR]

Photovoltaic thermal heat pump technology stands for the combination of solar heat pump technology and a photovoltaic system, which has the characteristics of tri-generation (heating, cooling, and electricity) to meet the building's energy requirement. In this paper, the dual-use photovoltaic thermal heat pump system was used and investigated experimentally with an emphasis on the refrigeration mode, which with the feature of the novel roll-bond photovoltaic thermal unit working as condenser directly. Moreover, renewable energy such as solar radiation and long-wave radiation are the main energy source of this system. The experimental investigation of the system comprising; 4 roll-bond photovoltaic thermal units, 1 horsepower heat pump unit and 600 L ice storage tank was carried out. The performance evaluation method and uncertainty analysis of the system was proposed and implemented along with the examination on the refrigeration performance and operating characteristics of the system. The results indicate that the proposed photovoltaic thermal heat pump system can achieve the refrigeration for building space cooling demand in summer with high performance and long-term stable operation. This study could provide a valuable reference for the photovoltaic thermal heat pump multi-generation system design and large-scale practical application in northern China. • A dual-use photovoltaic thermal heat pump system is investigated. • Longwave cold radiation and convection with air are energy sources for refrigeration. • Refrigeration performance of the system during summer is reported. • Operation characteristics of the system on refrigeration mode are presented. • The system can achieve refrigeration with high-performance for building demand. [ABSTRACT FROM AUTHOR]

Solar energy has expanded rapidly in recent years, and China is the largest market in terms of installed capacity. With the aim of achieving carbon neutrality by 2060, solar power will play an increasingly important role in China. However, like many other countries, the low energy density of solar photovoltaics is one of the major drawbacks of its further development. The emergence of floating photovoltaic systems (FPV) can not only break this threshold but also generate a series of cobenefits from a brand-new energy-land-water nexus perspective. Using a GIS-MCDA model, an evaporation model, combined with a cost-benefit analysis, this paper estimates the development potential of FPV in China, and its energy-land-water cobenefits are further analyzed. Moreover, to reveal the current land constraint for developing solar photovoltaics in China, the potential of traditional terrestrial solar photovoltaics has also been evaluated. The results show that the potential installed capacity of FPV in China can reach 705.2 GW–862.6 GW with an annual 1164.9 TWh to 1423.8 TWh of potential power output, and most potential FPV stations can obtain positive financial returns. The annual water evaporation reduction is approximately 5.8 km3. In the meantime, around 7117.3 km2 of the land could be conserved, which would alleviate the land constraint for terrestrial solar photovoltaic systems, especially in the highly urbanized eastern and southern coastal areas in China. [ABSTRACT FROM AUTHOR]

With the large-scale integration of wind and solar power in China, the consumption of these intermittent renewable energies is severely restricted by the capacity of the transmission channel, which leads to massive renewable energy curtailment. Therefore, it would be beneficial to use limited transmission channels to absorb as much renewable energy as possible. In this paper, we propose a chance constraint-based multistage nested hydro-wind-solar coordinated optimal scheduling model to aid peak shaving while ensuring maximum power generation. First, multistage partitioned section chance constraints are introduced to mitigate the power congestion of the transmission network. Then, based on the principle of using hydropower to complement the uncertainty of wind and solar power, the compensation chance constraints are considered. To quantify the uncertainty of wind and solar power, their prediction errors are analyzed using the Gaussian mixture model. Finally, the model is recast and linearized into a mixed integer linear programming model. A case study of a hydro-wind-solar base in Southwest China demonstrates that the proposed model can effectively leverage the regulation ability of hydropower to coordinate multiple power sources with the restrictions of multistage transmission sections, effectively alleviating the congestion of transmission channels and reducing the curtailment of renewable energy. [ABSTRACT FROM AUTHOR]

The renewable energy power generation (REPG) in China has experienced tremendous growth in the last decade. To understand this rapid growth, it is necessary to explore how Chinese government triggers the remarkable development of the industry. This paper offers a systematic analysis of the incentive policy system for REPG in China, covering wind power, solar photovoltaic, small hydropower (single-unit power generation capacity less than 50 MW), biomass power and geothermal power. The incentive system contains laws, regulations, policies and industrial plans issued during the 11th and 12th “Five-year Plan” periods (2006–2015). Four major incentive strategies of the Chinese government are identified: research and development incentives, fiscal and tax incentives, grid-connection and tariff incentives, and market development incentives. The results show these incentive methods have played a significant role in promoting the development of REPG in China, but still there are some problems associated with them. International comparisons of the incentive policies with those of Denmark, Germany and US, as well as the strategies to further improve the Chinese incentive approaches are discussed. This comprehensive analysis of China's incentive policy system for REPG helps to understand China's experience in promoting renewable energy, contributing to better decision-making in policy. [ABSTRACT FROM AUTHOR]

Abstract: The paper presents the complete design of a photovoltaic noise barrier (PVNB) installation that can be used either to supply local electrical loads or for sale using the premium subsidy awarded by the China government. Possible designs for the PVNB are investigated together with economic and environmental analysis. For the first time, a PVNB has been installed along a metro line in China. The installed power is 8 kWp and the total length of the PV array is 360 m. According to the site and environmental conditions, the form and electrical connections of PVNB have been determined. Net Present Value (NPV) and the Pay-Back Period are chosen as the parameters to determine the profitability of a PVNB installation. At the same time, energy pay-back time (EPBT) is used to evaluate the environmental benefits of PVNB systems; for the specific system analyzed the EPBT is 5.4 years. [Copyright &y& Elsevier]

Abstract: Creating better understanding between environmental quality and energy use, this paper collects 150 household energy use data sets, using questionnaires, from households in Lanzhou, China. Converted to kilograms of coal standardized energy equivalent, urban energy usage is calculated at a yearly rate of 490.37 kgce/a per capita and 1598.61 kgce/a per household. Types of emissions are also specified. Coal is the dominant energy source, and maximum environmental benefit is shown to be gained from substituting natural gas and solar energy for coal, and specific measures for substitution are identified. [ABSTRACT FROM AUTHOR]

With the rapid development of the Chinese economy, energy consumption has increased considerably, and this has increased pressure on energy production. On the other hand, this pressure has greatly assisted in the development of the renewable energy in the past two decades. This paper reports the latest developments in the solar thermal utilization in China. A great deal of successful examples of solar thermal utilization are presented. Issues of most concern and interest, which are resisting a further development of solar thermal utilization, have been identified and discussed. A prediction for the prospect of solar energy thermal utilization in China is also presented. [Copyright &y& Elsevier]