Almost all power plants that utilize a heat source rely on a single form of energy that is converted to electricity. The feeder energy is that contained in high-pressure steam. How that steam is generated depends upon the individual power plant and heat source. But in the end, the steam is generated by burning coal, oil, wood chips and other biomass, geothermal boiling, solar concentrator boiling, or nuclear power (amongst others). That high pressure, high temperature steam turns a steam turbine that rotates a shaft that spins a generator creating an electromagnetic field from which electrical energy is converted. It is simply a number of energy conversions from thermal to electrical energy. Prior to the generator, the cycle is called the Rankine cycle. Here is the very basic layout:
So we have water in a loop that gets pressurized to a high pressure through a liquid pump, then goes to a boiler (steam generator) where it is converted to steam. 
That steam flows through a turbine that contains many fan blades that turn a shaft as the steam flows through it. The turbine essentially converts the pressure energy into work (the turning of a shaft). The steam leaves the turbine lower-temperature and low-pressure with possibly some water present in some designs. That low-grade steam then goes to a condenser that converts the steam back into a liquid so that the pump can take it right back into the boiler and the cycle repeats over and over again. The heat rejected from the condenser goes into the environment and is lost. Each component is not 100% efficient, nor is the entire cycle. In fact, the most efficient cycle operating between two temperature extremes is called the Carnot cycle. For most plant designs, the Carnot cycle predicts a maximum efficiency allowed by the physical laws of nature in general, and the 2nd law of thermodynamics specifically, predicts a maximum possible efficiency in the range of 60%. Of course, we cannot design anything near that boundary, and thus most plants run between 30-40% efficient. 
That's simply a limit of the laws of physics, boundaries that we have to work within and really can do nothing about. Only He who imposes the law can repeal the law, and since we haven't imposed laws of nature, we cannot repeal them either, notwithstanding the wishful thinking of those ignorant to such laws. (more on that later)
Back to the Rankine cycle, the turbine is the primary generator of work in the form of a rotating shaft that then spins in a generator converting the work to electricity. The turbine is a very large device, in many cased the size of a large conference room. Here's a schematic and pic of one such turbine:
They get bigger than that too. That big shaft you see in the above pic goes directly into the electrical generator, which is basically an induction motor still basically similar to what Michael Faraday invented back in 1831:
It's too bad that Faraday didn't have a big turbine to turn the shaft. It was all manual back in that day... More on generators at HowStuffWorks.
That steam flows through a turbine that contains many fan blades that turn a shaft as the steam flows through it. The turbine essentially converts the pressure energy into work (the turning of a shaft). The steam leaves the turbine lower-temperature and low-pressure with possibly some water present in some designs. That low-grade steam then goes to a condenser that converts the steam back into a liquid so that the pump can take it right back into the boiler and the cycle repeats over and over again. The heat rejected from the condenser goes into the environment and is lost. Each component is not 100% efficient, nor is the entire cycle. In fact, the most efficient cycle operating between two temperature extremes is called the Carnot cycle. For most plant designs, the Carnot cycle predicts a maximum efficiency allowed by the physical laws of nature in general, and the 2nd law of thermodynamics specifically, predicts a maximum possible efficiency in the range of 60%. Of course, we cannot design anything near that boundary, and thus most plants run between 30-40% efficient. 
That's simply a limit of the laws of physics, boundaries that we have to work within and really can do nothing about. Only He who imposes the law can repeal the law, and since we haven't imposed laws of nature, we cannot repeal them either, notwithstanding the wishful thinking of those ignorant to such laws. (more on that later)Back to the Rankine cycle, the turbine is the primary generator of work in the form of a rotating shaft that then spins in a generator converting the work to electricity. The turbine is a very large device, in many cased the size of a large conference room. Here's a schematic and pic of one such turbine:
Previously:
The Fermi Chronicles - Part 11: Worldwide Uranium Availability
The Fermi Chronicles - Part 10: Utilizing Nuclear Reactions To "Breed" More Fuel
The Fermi Chronicles - Part 9: Nuclear Fission
The Fermi Chronicles - Part 8: Neutron Interaction
The Fermi Chronicles - Part 7: Radioactive Decay and Half-Life
The Fermi Chronicles - Part 6: Atomic Structures
The Fermi Chronicles - Part 5: Nuclear Waste Storage
The Fermi Chronicles - Part 4: Radiation Types and Radiation "Dose"
The Fermi Chronicles - Part 3: Radiation Types
The Fermi Chronicles - Part 2: A week of training
The Fermi Chronicles - Part 1: The alpha post
The Fermi Chronicles - Part 11: Worldwide Uranium Availability
The Fermi Chronicles - Part 10: Utilizing Nuclear Reactions To "Breed" More Fuel
The Fermi Chronicles - Part 9: Nuclear Fission
The Fermi Chronicles - Part 8: Neutron Interaction
The Fermi Chronicles - Part 7: Radioactive Decay and Half-Life
The Fermi Chronicles - Part 6: Atomic Structures
The Fermi Chronicles - Part 5: Nuclear Waste Storage
The Fermi Chronicles - Part 4: Radiation Types and Radiation "Dose"
The Fermi Chronicles - Part 3: Radiation Types
The Fermi Chronicles - Part 2: A week of training
The Fermi Chronicles - Part 1: The alpha post
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