WIND CAPACITY LIMITS
It is clear from figures already quoted that there is, in principle, enough wind energy to supply global electricity demand 20 times over, or more. There would appear to be no limit, therefore, to the amount of electricity that might be generated from wind turbines except under exceptional regional circumstances.
What will limit wind power is the amount of wind energy that can be satisfactorily managed on grid systems without endangering grid security and reliability. This limit will depend on the availability of the means of providing energy when the wind does not blow, including energy storage and alternative power sources. Various estimates have been made in the past for the amount of wind energy that can be absorbed, practically, on modern grids. However, the best way of assessing what is practical is to look at the proportion of wind capacity on existing grids where wind penetration is high.
The highest wind penetration in the world in on the Danish grid where 29% of power was provided by wind energy in 2012. Denmark has links with neigh- boring countries and so can export excess wind power allowing it to use most of the wind energy it generates. Elsewhere, countries have had problems absorbing all the wind energy they generate. Germany, with 11% of its electricity supplied by wind power in 2012, has often had to curtail wind power during periods of high output because its transmission system does not allow large amounts of power to be transmitted from the north, where most wind generation is situated, to demand centers in the south.
Germany’s problem can be solved with grid modification. Meanwhile, the International Energy Agency has estimated that a grid such as that in Denmark would be capable of managing around 60% wind penetration—that is, 60% of all electricity could be provided by wind capacity—although others countries might have lower capabilities. This suggests that with appropriate adaptation and grid integration, perhaps as much as 50% of the power on a typical modern grid might feasibly be provided by wind power. Whether that is desirable is probably more a matter of politics than technology.