TABLE OF CONTENTS Why was it necessary to develop the high-voltage grid? Even back in 1926 it was clear that, as the electricity industry was developing, the need to transmit power longer distances was growing. This was not just to allow power to be transferred between neighbouring companies among the 400 or so selling electricity: it also enabled the network as a whole to take advantage of economies of scale. Steam turbines could be made to work more efficiently as the size of the boiler and turbine increased, so the cost of a unit of electricity produced decreased. At the same time, economies of scale could be made, once again reducing the capital cost per unit of electricity.
Other pressures also drove the trend for larger power stations sited further from the areas where electricity was used (the 'load' centres). For steam turbines, one reason for the shift was the need to transport huge amounts of fuel to the big new stations.
One of the valuable characteristics of coal is that it can be bought, and transported, from many suppliers worldwide. But the downside is that there can be huge financial and environmental costs in transporting coal from the mine to the power station. If the power station owner is willing to link the plant closely to a single mine, it is much more efficient to build so-called 'mine mouth' power stations to minimize the distance that the coal has to be transported. There are other potential benefits to...
