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The power system ranks the first among the greatest engineering achievements in the 20th century. With “strong electric power” as the carrier, the power system constitutes the great aorta of modern society for energy transmission; while with “weak electric power” as the carrier, the information network constitutes the nervous system of modern society. Both of them penetrate into all aspects of human society (e.g., science, production, life, international relations), and then promote the modern civilization to achieve rapid development. In terms of science, the power system has promoted the developments of materials, physics, chemistry, automation, information, medicine, and so on. This way, the system of modern science and technology is constituted. In terms of production, the second industrial revolution marked by the wide application of “strong electric power” is also called the electric power technology revolution. It has promoted another major leap in the productivity of human society after the steam revolution. The third industrial revolution marked by the widespread application of “weak electricity” is also known as the information technology revolution, which promotes the continuous evolution of industrial civilization to a much higher level. And the fourth industrial revolution, which is centered on the energy revolution, will meet the needs of human beings at a higher level and get rid of the constraints of the environment on human activities. In terms of life, electric power has become the most indispensable part of human life, ranging from material life to spiritual life, from behavioral habits to thinking ways, and from personal life to social life. In terms of international relations, the development of the power system is conducive to the fundamental solution of energy and environmental problems, thus the international political and economic competition around energy and environment has turned to the competition centered on clean power systems to some extent. As the basic platform for energy production and supply, the development of the future power system must follow the general orientation of the energy revolution. The basic form, management mechanism and technical characteristics of the power system will also undergo tremendous changes as follows: (1) The proportion of renewable energy in the power system will be increased continuously, and the power system will be tightly coupled with gas system and thermal system to form an electricity-centric energy internet. (2) The development mode of building “higher, farther and larger” power grid will turn to the co-development mode of large power grid and small power grid, and the trend of power electronation of power system will be strengthened gradually. (3) Market competition will penetrate into the weak monopolies of the power system. Each subject can play a full game in each link, so as to obtain the optimal allocation of funds, technology and human resources. (4) Digitalization and intellectualization will be the most important technical characteristics of the future power system, which will achieve leapfrog development in observability, controllability and intellectualization.

International economic cooperation accelerates the flow of capital, technology, labor, and other factors between different countries, which promotes global sustainable development. Building infrastructure construction is an important way to strengthen social development, and absorbing foreign capital is an effective way for developing countries to improve their infrastructure and to promote economic development. This study puts forward the factors that have influenced China’s investment in international engineering projects, and it constructs a panel data regression model for empirical testing. The study shows that, first, international infrastructure investment tends to select countries or regions with good condition of highway infrastructure. Second, international infrastructure investment tends to choose countries or regions with low development level of port and power infrastructure. Third, bilateral diplomatic visits play a significant role in promoting international infrastructure investment. Fourth, international infrastructure investment tends to choose countries or regions with good resource endowment. This study reveals the influencing factors and the mechanisms for the choices of location for China’s investment in international engineering projects, providing a theoretical framework for investors to optimize international infrastructure investment and management, as well as providing the policy references for developing countries to attract international infrastructure investment.

As green communication becomes an inevitable trend for future 5G wireless networks, how to maximize the energy efficiency (EE) of device-to-device (D2D) communication has drawn extensive attention recently. However, most of existing works only optimize the EE in the single-cell scenario, while little attention is paid to maximizing the EE of the whole cellular network underlaid with D2D communication with randomly distributed users on multiple bands. In this paper, we first consider the whole cellular network underlaid with D2D communication on multiple bands and derive the exact expressions of the successful transmission probabilities, the average sum rate and the EE based on stochastic geometry theory. Then, we formulate the optimization problem of maximizing the EE subject to four constraints regarding to transmission power and outage probabilities, and the non-convexity of this problem is also verified. After that, by exploiting the objective function property of being the sum of several functions, we propose a derivative-based algorithm to solve this non-convex optimization problem. Our theoretical analysis shows that the computational complexity of the proposed algorithm is significantly lower than that of the conventional branch and bound algorithm. Finally, simulation results demonstrate that the proposed algorithm can achieve the near-optimal EE with much better performance than the conventional algorithm.

Despite many years of substantial government research funding, advanced bio-energy technologies in China have seen limited commercial application. Chinese policy makers are increasingly critical of academic organizations for neglecting their role in the transfer of scientific results into industrial applications. We interviewed a selection of Chinese research groups working on bio-energy technologies, and asked them to describe their efforts at commercialization. We found that they focus their research on technological pathways with commercial potential, they patent and attempt to license their technologies, they are highly involved in large scale demonstration plants, and have created a number of new firms. Industry and government may have unrealistic expectations on the maturity and scale of technologies that academia can develop, however. These findings contrast with many earlier analyses of early commercialization stages of novel technologies, which have commonly identified lacking academic entrepreneurship as a root cause in stalling development

In this paper, we review the emerging challenges and research opportunities for voltage control in smart grids. For transmission grids, the voltage control for accommodating wind and solar power, fault-induced delayed voltage recovery, and measurement-based Thevenin equivalent for voltage stability analysis are reviewed. For distribution grids, the impact of high penetration of distributed energy resources is analyzed, typical control strategies are reviewed, and the challenges for local inverter Volt–Var control is discussed. In addition, the motivation, state-of-the-art, and future directions of the coordination of transmission system operators (TSO) and distribution system operators (DSO) are also thoroughly discussed.

The tradeoff between economic growth and environmental protection has been a critical issue in facilitating eco-industrial park development in China. As the principal contributors to China's industrial output, many industrial parks have been addressing the issues of intensive resource consumption and pollutant generation, driven by much stricter regulations on the environment and resource management. Retuning the industrial structure is a substantial way to address the environmental issues while promoting economic development, which are the goals of eco-industrial development. This study proposes a multi-criteria industrial structure adjustment model by employing a generalized reduced gradient method to find the optimal structure of an industrial park. The model aims to increase the overall resource utilization efficiency and industrial output efficiency through a decoupling between the economic development and environmental burden of the park. A Chinese eco-industrial park located in the capital, the Beijing Economic-technological Development Area (BDA), is used as an example to uncover a transformation roadmap from a high-speed mode to a high-quality mode. The constraints of the multi-criteria decision-making model mainly focus on the limits of water consumption and pollutant emissions by targeting an appropriate economic development rate. The key findings are as follows. First, BDA could achieve 186% economic growth with 20% water consumption and 30% contaminant reduction in five years (2020-2025) by optimizing the industrial structure. Second, the advanced manufacturing industries play significant roles in stimulating the high-quality development. Third, ammonia nitrogen is a crucial factor restricting economic development under the requests of the "dual control" policy. Forth, the industry that can use reclaimed water in production will get more development opportunities and space, and vice versa. The model can be applied in diverse industrial parks by modifying the parameters and associated constraints.

Sustainable development has become a global consensus, and green innovation is the key starting point, and it has become a ballast stone and stabilizer for regional ecological environmental protection and high-quality economic development. Based on GIS tools and multi-method models, this paper studies the spatio-temporal characteristics and influence mechanism of green innovation in three major urban agglomerations in China from 2010 to 2019 from the perspective of economic geography. The study found that: (1) the green innovation efficiency of the three major urban agglomerations in China is in a fluctuating upward trend as a whole, with obvious spatial disequilibrium; (2) from the spatial point of view, the characteristics of global spatial agglomeration distribution have positive spatial correlation, and the law of local spatial autocorrelation is obvious, and the spatio-temporal pattern transitions from “low efficiency, big difference” to “high efficiency, small difference” during the study period; (3) there are obvious spatial spillover and diffusion effects on the green innovation efficiency of the three major urban agglomerations in China as a whole. However, the spatial dependence of green innovation efficiency is inconsistent in China’s three major urban agglomerations; the YRD Urban region and the PRD Urban region show a positive impact, while the JJJ Urban region shows a negative impact; (4) the level of economic development, the operating environment of science and technology, and the guiding factors of government system function with significant differences and regional spatial heterogeneity on the efficiency of green innovation in the three major urban agglomerations in China.

In the restructured power industry environment, the economic impact assessment on transmission expansion from a societal perspective is indispensable. This paper proposes a method on this subject. Firstly, we introduce the classical economic assessment indices, and then present several basic concepts on power industry economics. Based on these, the paper proposes an integrated economic impact index on transmission expansion. The index takes the equity aspect as well as the efficiency aspect into account. The concepts of the classical utilitarianism social welfare function and the Lorentz curve and the corresponding Gini coefficient are introduced to measure the efficiency impact and the equity impact of a transmission expansion, respectively. The index can be used to guide the search or the selection of an optimal transmission expansion scheme from the societal perspective. Next, we use a six-node system case to illustrate the application of the index proposed. Then, we present a conclusive statement to end the paper.

Price rising of energy and the limitation of fossil fuel makes it an inevitable tendency to introduce distributed energy such as renewable energy to the existing supply system in the future. Different players, such as power generation, transmission, and distribution, along with the value chain must now cooperate and interact with each other by shared interfaces or eventually a customized network for secure and reliable delivery of energy. While smart grids are focusing on the informationization and intellectualization of the existing power grid, the new concept of an energy internet is proposed as an internet-style solution for energy issues by integrating information and power flows bi-directionally, which can be considered as the version 2.0 of smart grids. Some key features of an energy internet compared with conventional energy grid such as openness and peer-to-peer are introduced. Architecture of an energy internet is proposed in details, including energy storage, switches and routers. The definition of an energy internet call for a much greater degree of interactive flexibility for efficient energy management than the present system is designed to handle.