Thermal Power
Burns fossil fuels (coal, LNG, oil) to boil water, using the resulting steam to spin a turbine and generate electricity. Fuel is combusted in a boiler to create high-temperature, high-pressure steam, which drives the turbine; the turbine's rotation, transferred to a generator, produces electricity through electromagnetic induction, after which the spent steam is condensed back to water and recirculated. Components: boiler, turbine, generator, condenser, cooling tower. Pros: output can be adjusted relatively easily to match demand, and construction costs are comparatively low with long-mature technology. Cons: emits COβ and other greenhouse gases plus particulate pollution, and relies heavily on imported fuel.
Nuclear Power
Uses the enormous heat released by nuclear fission of uranium to create steam that spins a turbine β broadly similar to thermal power except for the heat source. Inside the reactor, uranium-235 nuclei split in a chain reaction upon colliding with neutrons, releasing massive heat that heats circulating coolant to produce steam (in pressurized-water reactors, primary and secondary loops are kept separate so radioactive material never reaches the turbine side); control rods are inserted or withdrawn to regulate the fission rate and output. Components: reactor, control rods, steam generator, turbine, generator, containment building. Pros: produces very large amounts of power from little fuel with almost no COβ emissions during generation, and can supply large-scale power reliably around the clock regardless of weather. Cons: radioactive waste disposal is a persistent issue, potential accidents can be severe, and construction takes a long time with very high upfront costs.
Hydroelectric Power
Uses the force of falling water from a height (potential energy) to spin a turbine directly. Water stored behind a dam or reservoir holds potential energy, which converts to kinetic energy as it falls through a penstock; unlike thermal or nuclear power, the fast-moving water directly spins the turbine (water wheel) blades without going through steam, and the connected generator produces electricity. Components: dam, penstock, water turbine, generator. Pros: no fuel cost and no pollutants emitted during generation, plus output can be adjusted almost instantly, useful for balancing electricity supply (e.g. pumped storage). Cons: suitable terrain for dam construction is limited, with major ecological and community impact during construction, and output can vary greatly with rainfall.
Solar Power
Solar cells convert sunlight directly into electricity with no turbine or generator involved. Solar cells are made of semiconductor material (typically silicon); when light (photons) strikes them, the photovoltaic effect knocks electrons loose inside the semiconductor, and the resulting flow of electrons produces direct-current (DC) electricity, which is converted to the alternating current (AC) used in homes and factories via an inverter. Multiple cells bundled together form a module, and multiple modules connected together form the familiar solar panel. Components: solar cell, solar module (panel), inverter. Pros: no rotating parts like turbines means low noise and comparatively simple maintenance, and it can be installed at various scales and locations, from rooftops to idle land. Cons: no generation at night or on cloudy days makes output unstable, and a relatively large area is needed to achieve the same output as other methods.
Wind Power
Uses the kinetic energy of wind to spin large blades that drive a generator. Wind generates lift on blades engineered similarly to an airplane wing, causing them to rotate; since blade rotation speed is relatively slow, a gearbox steps it up to a speed at which the generator operates efficiently, and the spinning generator produces electricity via electromagnetic induction, while the nacelle housing the generator automatically turns to face the wind direction for maximum capture. Components: blades, nacelle, gearbox, generator, tower. Pros: no fuel cost and no pollutants emitted during generation, and it can be installed both onshore and offshore, giving relatively varied siting options. Cons: inconsistent wind strength makes output hard to predict, and there are concerns about noise, visual impact on the landscape, and bird collisions.
Tidal Power
Uses the difference in sea level between high and low tide to spin a turbine. A bay or estuary is enclosed with a barrage to create an artificial reservoir; seawater flows in through sluice gates during high tide and back out during low tide, and as it passes through, it spins turbines installed in the gates, with the connected generator producing electricity (some designs generate in both directions, on both the incoming and outgoing tide). Components: barrage, sluice gates, turbine, generator. Pros: the regularity of tidal patterns makes output very predictable, and there's no fuel cost or pollution during generation. Cons: suitable sites with a large tidal range and the right terrain are very limited, and barrage construction can severely damage tidal-flat ecosystems.
Geothermal Power
Uses heat deep underground to create steam or hot fluid that spins a turbine. In areas with active geothermal activity, such as volcanic zones, hot rock or magma deep underground heats groundwater into high-temperature, high-pressure steam or hot water; wells are drilled to bring this steam to the surface, where it either spins the turbine directly (dry-steam systems) or heats a separate working fluid that then spins the turbine (binary systems); the connected generator produces electricity, and used water is reinjected underground to recirculate. Components: production well, steam separator, turbine, generator, reinjection well. Pros: can generate reliably around the clock regardless of weather or season, and fuel costs are minimal once facilities are built. Cons: areas with good geothermal conditions, such as volcanic zones, are limited, and initial drilling and exploration costs are high with real risk of failure.
Biomass Power
Generates electricity from energy obtained by burning or fermenting organic matter such as wood, agricultural byproducts, and livestock manure. Organic matter (biomass) β wood pellets, agricultural byproducts, livestock manure, waste wood β is used as fuel; as with thermal power, this fuel is burned to boil water and spin a turbine with the resulting steam, and some approaches instead use biogas (such as methane) produced by fermenting organic matter as fuel. In principle it can be close to carbon-neutral, since the COβ released on combustion roughly matches what the plants absorbed while growing, though the carbon emitted during logging and transport must be considered separately. Components: biomass fuel (e.g. wood pellets), boiler, turbine, generator. Pros: can partly reuse existing thermal power infrastructure while displacing fossil fuels, and it can recycle agricultural, livestock, and other waste as an energy source. Cons: logging for fuel wood can raise deforestation concerns, and combustion can release particulate matter and other air pollutants.
Wave Power
Uses the up-and-down motion of ocean waves to drive a turbine or generator. A buoy floating on the sea, or a coastal structure, rises and falls with the waves to capture kinetic energy; this up-and-down motion compresses internal air or drives a hydraulic system, and the compressed air or hydraulic pressure spins a turbine, with the connected generator producing electricity. Components: buoy, hydraulic/pneumatic system, turbine, generator. Pros: waves are more predictable than wind, giving relatively less output variability, and the potential is large in regions with long coastlines. Cons: still in an early commercialization stage with relatively high generation costs, and salt water and wave action place a heavy burden of corrosion and maintenance on equipment.