China
Africa
Explore chapters and articles related to this topic
Overview of Smart Power Systems
Published in KTM Udayanga Hemapala, MK Perera, Smart Microgrid Systems, 2023
KTM Udayanga Hemapala, MK Perera
A conventional power grid consists of four main sections, as shown in Figure 1.1, namely generation, transmission, distribution, and utilization. Conventional power systems are based on large, centralized power generating stations. In most of these power stations, the electricity is generated by burning a fossil fuel and producing steam, which is then used to drive a steam turbine that in turn drives an electrical generator. In addition, conventional generation relies on nuclear power plants or major hydro plants where the capacity of the plant is in the MW range. The generated energy is delivered to the end user through complex transmission and distribution systems. Here, step-up transformers are used to increase the voltage to transmit the electricity to consumer centers, then the voltage is reduced for distribution using step-down transformers. Finally, the electricity comes to the consumer at a specified voltage and with the specified frequency at minimum cost. This process appears seamless to the end user. For example, when you flip a switch the electrical equipment is turned on. However, the existing power network is often described as the most complex machine ever built. It is a real-time energy delivery system. The main goal of the power system is to cater for loads with electricity at the specified voltage and frequency at minimum cost consistent with operating constraints, safety, and so on.
Power Stability and Quality
Published in Michael F. Hordeski, Emergency and Backup Power Sources:, 2020
Distributed power generation means placing energy generation and storage as close to the point of consumption as possible with maximum conversion efficiency and minimal environmental impact. Typically, centralized power stations are over-designed to allow for future expansion and so they run for most of their life at a reduced efficiency. They also represent a higher financial risk to the owner because of the greater amount of investment in a single plant.
Introduction to Microgrids
Published in Stephen A. Roosa, Fundamentals of Microgrids, 2020
The categories of the energy we use for electrical generation are divided unevenly into nonrenewable sources; carbon-based energy sources such as coal, oil, and oil shale; and renewable sources such as wind power, solar, geothermal, and gravitational water sources. A conventional power station, also referred to as a power plant, powerhouse, generating station, or generating plant, is an industrial facility for the generation of electric power. Most power stations contain one or more generators, rotating machines that convert mechanical power into electrical power. Conventional power stations typically use fossil fuel-fired generators, most notably coal, natural gas, and nuclear power, using the Rankin cycle. However, there are many others that use renewable technologies such as hydroelectric dams and large-scale solar power stations. Such stations are centralized and require electric energy to be transmitted over long distances [1].
Influence of China’s Overseas power stations on the electricity status of their host countries
Published in International Journal of Digital Earth, 2022
Xumiao Gao, Mingquan Wu, Chao Li, Zheng Niu, Fang Chen, Wenjiang Huang
Figure 9 shows the numbers and percentage changes in start-ups of each type of power station over time. Figure 9(a) shows that the number of COPS ‘contracts and start-ups’ has increased gradually since 2006. The number of renewable COPS start-ups increased significantly after 2013, and the number of power TDPs increased significantly after 2016. According to Figure 9(b), since 2006, the proportions of thermal and hydropower projects have declined, whereas the proportions of renewable projects and TDPs have increased significantly since 2010. After 2016, the number and proportion of renewable power stations increased significantly. This is because the Chinese government put forward the policy Guiding Opinions on Promoting the Construction of Green Belt and Road Initiative in 2017. Overall, a trend from thermal to renewable energy COPSs is gradually emerging, and from construction to the coordinated development of COPSs with TDPs, which have positive impacts on SDG7.2.1 and SDG7.b.1. On September 21, 2021, China's President Xi Jinping announced that China will strongly support the development of green and low-carbon energy projects in developing countries and will no longer participate in new coal-fired electricity projects. Hence, renewable power stations will become the main type of COPS Figure 10.
Techno-economic analysis of thermoelectrics for waste heat recovery
Published in Energy Sources, Part B: Economics, Planning, and Policy, 2019
The vast majority of heat engine designs rely upon the combustion of fossil fuels to either directly or indirectly expand a piston or rotate a turbine, thereby converting chemical energy into mechanical energy. The gas stream exiting the cylinder or turbine is at an elevated temperature relative to the surroundings and is either released to the atmosphere directly (open cycle), or indirectly through a heat exchanger (closed cycle). It is possible to utilize this elevated temperature stream to generate additional power by feeding it into a second cycle. Power generation facilities that utilize at least two cycles can achieve fuel efficiencies of > 50% (Franco and Casarosa 2002). Whilst it is increasingly common for large-scale facilities to utilize waste heat streams to produce additional power, an absence of carbon taxes and the relatively low cost of fossil fuels has hindered the uptake of waste heat recovery at lower energy output levels. In electrical power stations, the mechanical energy produced from the combustion process is converted into electrical energy through an electrical generator. Thermoelectric generators (TEGs) are an alternative method of converting heat directly into electrical power and can act as either an alternative to secondary cycles or in addition to a secondary cycle. Although they are a type of heat engine, their operation is based upon the thermoelectric effect, which is a fundamentally different mechanism of electrical power generation.