The amount of wind power that can actually be exploited is likely to be limited, eventually, by the amount of wind generated power national transmission systems can accept. The actual proportion remains a matter for debate but the Danish power industry has shown that it is possible to accept 20% wind energy without detrimentally affecting grid operation.
The problem lies in the fact that wind is not a reliable resource. The output from a wind turbine cannot be guaranteed from day to day. Over a wide area, some variability will be averaged out, but nevertheless a significant level of uncertainty will remain. Better wind forecasting will help reduce the short-term uncertainty but long-term fluctuations in wind output are unavoidable.
Faced with this uncertainty, power dispatchers cannot depend on wind for base-load generation. When wind power is available they can use it to displace other types of generation. When it is not, they must bring those other plants into service.
The situation can be alleviated somewhat by building additional storage capacity on the grid to absorb the fluctuations. Even so, there is a limit to the amount of uncertain power of this type that a system can support with ease. It is possible to operate wind farms with less uncertainty if they are rated more conservatively but that means operating at below full output for most of the time, a strategy which will increase overall cost.
Offshore wind farms present an additional problem because the power from the generating facility must be delivered to the national grid at a point on the coast. In general coastal grids are not particularly good places to make such a connection. The grid can be strengthened in order to make it capable of accepting a large input of power but this will raise the cost of offshore wind power.
Was this article helpful?