Power Plant
Overview
A power plant (發電所) is a large-scale industrial facility that converts the chemical energy of fuels, nuclear energy, the potential energy of water, and natural energy sources such as wind and solar into electrical energy and supplies it to the power grid. As the core node of modern society's electricity infrastructure, the types and composition of power plants are directly tied to a nation's energy security, carbon emissions, and electricity prices. In recent years, redesigning the power generation mix under the twin pressures of decarbonization and surging electricity demand has become a major policy challenge.
Main Content
Basic Principles of Power Generation
Most power plants produce electricity by rotating a turbine that drives a generator. This relies on Faraday's law of electromagnetic induction, in which a rotating magnet (the rotor) induces an electromotive force in a coil (the stator). Thermal, nuclear, hydroelectric, and wind power all share the same skeleton of "turbine + generator," even though the working medium differs. Solar photovoltaics, by contrast, convert light directly into electricity through the photoelectric effect in semiconductors, and fuel cells use the electrochemical reaction of hydrogen and oxygen, making them structurally distinct.
Thermal Power Plants
Thermal plants burn coal, LNG, heavy oil, biomass, and similar fuels to produce high-temperature, high-pressure steam in a boiler, which is then supplied to a steam turbine to drive a generator. Efficiency is typically around 40–45%, and combined-cycle gas turbine (CCGT) plants, which use the exhaust heat of a gas turbine to drive a steam turbine again, can raise efficiency to over 60%. Denitrification, desulfurization, and electrostatic precipitator facilities to remove nitrogen oxides, sulfur oxides, and particulate matter from exhaust gas are essential, and cases combining carbon capture, utilization, and storage (CCUS) facilities are increasing. Because construction periods are short and output control is flexible, thermal plants have handled the intermediate load of the grid, but coal power is on a declining trajectory due to carbon emission concerns.
Nuclear Power Plants
Nuclear plants produce steam using the heat from uranium fission and are a representative carbon-free power source that emits almost no carbon dioxide during operation. Pressurized water reactors (PWR) and boiling water reactors (BWR) are the main commercial types, and multiple redundant defense designs for safe shutdown and cooling systems are core requirements. With a low share of fuel costs and a capacity factor exceeding 90%, they are suitable for baseload, but they entail high construction costs, long construction periods, and the unresolved issue of final disposal of high-level radioactive waste. Recently, small modular reactors (SMRs) with output reduced to 300 MWe or less are emerging as an alternative that lowers the burden of investment and siting.
Hydroelectric Power Plants
Hydroelectric plants turn water wheels using the head (drop) of water and are divided into dam-type, diversion-type, and pumped-storage types. Because they can ramp output up and down very quickly, they are advantageous for grid frequency regulation and securing reserves. Pumped storage in particular functions as a large-scale energy storage facility that pumps water upward using surplus electricity and releases it when needed, and its value is being reassessed as the share of renewable energy grows.
Renewable Energy Plants
These include solar photovoltaics, onshore and offshore wind, bioenergy, geothermal, and tidal and wave power. They have the advantage of no fuel costs and low carbon emissions during generation, but they suffer from the structural limitation of intermittency, as output varies with irradiance and wind speed. Accordingly, output forecasting, integration of energy storage systems (ESS), securing backup power, and expanding flexible resources are required together.
Grid Connection and Transmission/Distribution
Electricity produced at power plants is delivered to demand centers via step-up transformers, transmission lines, and substations. Because electricity is difficult to store in large quantities, supply and demand must match in real time, and to this end generation planning, frequency regulation, and reserve procurement are managed by the system operator. Plant siting is determined by a combination of factors including fuel procurement, cooling water availability, transmission line construction, environmental impact assessment, and local community acceptance. Economic feasibility is often compared using the levelized cost of electricity (LCOE), which combines construction and operating costs.
Latest Trends
The biggest current of 2024–2025 is the simultaneous progression of "decarbonization" and "surging electricity demand." First, as electricity demand turns back to growth for the first time in decades due to AI data centers and electrification (electric vehicles, heat pumps, and industrial electrification), investment in generation facilities and transmission networks is being reexamined. Second, the phased reduction of coal power, conversion to LNG, and expansion of renewable energy are proceeding in parallel, and flexible resources such as ESS, pumped storage, virtual power plants (VPP), and demand response (DR) are being incorporated into the institutional framework to address intermittency. Third, SMRs are entering the licensing and construction stages at regulatory authorities in various countries, and discussions on commercial contracts as dedicated power sources for data centers have begun in earnest. Fourth, demonstration of co-firing with hydrogen and ammonia is underway, exploring low-carbon conversion pathways for existing thermal facilities. Fifth, digitalization of operation and maintenance—such as digital twins, AI-based generation forecasting, and predictive maintenance (PdM)—is spreading, improving both capacity factors and safety. Domestically, centered on the Basic Plan for Electricity Supply and Demand, the balance between nuclear utilization and renewable expansion, resolving grid connection queues, and activating distributed energy are being addressed as major issues.
Related Topics
- [[Power Grid]]
- [[Nuclear Power Generation]]
- [[Renewable Energy]]
- [[Energy Storage System]]
- [[Carbon Neutrality]]