Stage 2
LMS guide
Conventional Method (Fossil Fuels) |
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This page is about the conventional method for generating electricity, burning fossil fuels.
Many people see electricity as a clean energy source, much better for the environment than cars. There are no fumes, so it is obviously better. This is very wrong because the difference between the power source in cars and houses is that for houses the fumes are created at power stations, before the energy gets to the house.
Most energy used in houses comes from fossil fuels. Fossil fuels are fuels including coal, petrol and natural gas. They are called fossil fuels because they are naturally occurring. For example, coal is basically compressed plant matter.
These fossil fuels are turned into electricity by being burnt. When they are burnt, they are used to heat water, which evaporates into steam (number 1 on the diagram). This steam turns large turbines (2), which in turn cause large electromagnets to spin. This is the basis for the dynamo, or generator (3). Spinning magnets cause electrons to move along a wire, which is electricity.
Original diagram courtesy of: http://americanhistory.si.edu/powering/generate/gnmain.htm
This diagram clearly illustrates the process of electricity generation.
Efficiency
Electricity from fossil fuels is also not very efficient. The formula for efficiency is output divided by input multiplied by 100
Law of Conservation
If power plants were closed systems, these energy losses would not occur, because of the law of conservation, which states that in a closed system, energy cannot be destroyed or created, only transformed into other kinds of energy. Instead, the power plant would be 100% efficient.
Energy Transformation
The goal of steam turbines is to turn kinetic energy into mechanical energy. The moving steam is the kinetic energy and the end product, the electricity is the mechanical energy.
After all this, when the fossil fuel has been turned into steam, the average efficiency of a power plant is 88%. Not all of the steam is effective in turning the turbines, so after the remaining 88% has been put through the turbines, the final amount of power is between 30 and 35% of the starting power. So, power plants are 30 to 35% efficient. If a power plant used 2400MW of power to produce electricity, it would produce 840MW of electricity.| Name | Version | Size | Date | User |
|---|---|---|---|---|
| electrogeneration.jpg | 1 | 38609 | 6/13/05 6:01 PM | Henry |
Last Modified 6/13/05 6:38 PM