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Electrical grid: Difference between revisions
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The amount of generation necessary at any time is called the load. Base load is the level that demand usually does not drop below, and it varies seasonally. Intermediate load is required while people are awake and using more electricity. And peak loads are spikes in use, typically when people get up and in the evening. Daily fluctuations in load are fairly predictable, and generation is dispatched accordingly. | The amount of generation necessary at any time is called the load. Base load is the level that demand usually does not drop below, and it varies seasonally. Intermediate load is required while people are awake and using more electricity. And peak loads are spikes in use, typically when people get up and in the evening. Daily fluctuations in load are fairly predictable, and generation is dispatched accordingly. | ||
In addition, reserve plants are | In addition, reserve plants are kept operating – burning fuel but not generating power – so that backup power is continuously available, ready to take over in case of the sudden loss of another plant. This operating reserve makes it possible to readily integrate a small amount of variable nondispatchable generators such as wind turbines into a grid, but using them for that purpose obviously reduces their availability for responding to a catastrophic loss of other generators. | ||
Nuclear and large coal plants are used to provide base load, because they can not be rapidly turned on or off. In fact, it may take days to start up such plants. Their production of electricity, however, can be ramped down by diverting the steam away from the generator turbines, but this does not reduce the amount of fuel consumed. | Nuclear and large coal plants are used to provide base load, because they can not be rapidly turned on or off. In fact, it may take days to start up such plants. Their production of electricity, however, can be ramped down by diverting the steam away from the generator turbines, but this does not reduce the amount of fuel consumed. | ||