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Name: Tom R.
Status: Other
Age: 20s
Location: N/A
Country: N/A
Date: 2002

Hello, I understand how electricity is generated using steam turbines, at least in a general way. The thing that confuses me is how the amount of power generated by a power plant is increased. For example, how does a power plant go from generating 20 MW to generating 40 MW? Originally, I though the plant would simply create more steam, thus spinning the turbine faster. The problem, of course, is that would increase the output frequency of the Generator and make it incompatible with the rest of the grid.

One way to increase the output of an existing plant is to try and run the steam at a higher pressure and temperature. This usually involves superheating the steam or increasing the feed rate of the coal. There are also little things you can do like feedwater heaters, higher efficiency heat exchangers, higher efficiency turbines, etc. These mechanism will increase the output of the turbines and thus increase the megawatt output. If you look at some thermodynamics books, you can get a better idea of how these systems work if you look into Rankine cycle information.

Unfortunately I do not know the details of how to get the electricity out into a grid system. Hopefully an electrical engineer will answer the other portion of your question.

Chris Murphy, PE

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