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Electrical grid: Difference between revisions
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(Created page with "The electrical grid is the vast network connecting generators and users of electricity. Because alternating current can not be stored, the grid is managed so that the amount...") |
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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. | ||
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. | |||
Other dispatchable sources can also provide base – as well as intermediate and peak – load, but nondispatchable sources such as wind can not. Wind energy is produced in response to the wind instead of actual demand on the grid. It thus acts like “negative demand”, and the grid must adjust other sources to balance the fluctuating and largely unpredictable infeed from wind turbines as well as the more predictable user demand. This causes the grid to operate less efficiently, including causing fossil fuel plants to burn more fuel – and emit more CO<sub>2</sub> etc. – in relation to the electricity produced. It is analogous to stop-and-go city versus highway driving. | |||