Why are Power Grids so Large?

broadgage:

Large and interconnected power grids not only increase reliability whilst only needing a modest level of spare capacity, but also permit of larger and more economic generating plant.

Modern alternators are often of about 500Mw capacity, easy to connect to a large grid but too big for a single town.

At times of low load, several large generating units can be run at efficient loadings, far better than ten towns each running plant at low load, and requiring staff.


Also, exceptionally large loads can be connected to a large grid system, loads that be beyond the capacity of a small town system. Electric railways are a good example, with single phase loads of many Mw that are continual varying. Want of a large interconnected grid often resulted in continuation of steam locomotives when electric power would otherwise have been more suitable.

Large electric arc furnaces are another example.

broadgage:

Large and interconnected power grids not only increase reliability whilst only needing a modest level of spare capacity, but also permit of larger and more economic generating plant.

Modern alternators are often of about 500Mw capacity, easy to connect to a large grid but too big for a single town.

At times of low load, several large generating units can be run at efficient loadings, far better than ten towns each running plant at low load, and requiring staff.


Also, exceptionally large loads can be connected to a large grid system, loads that be beyond the capacity of a small town system. Electric railways are a good example, with single phase loads of many Mw that are continual varying. Want of a large interconnected grid often resulted in continuation of steam locomotives when electric power would otherwise have been more suitable.

Large electric arc furnaces are another example.