5.2.4.3 Power utilisation and storage

 

The maximum electrical output from a wind turbine can only be realised if its power can be applied whenever the wind chooses to blow. All energy sources have some problem of this kind, and one advantage of wind energy (see fig 5.12) is that the wind blows harder during the winter when there is a greater demand for electricity. But because the wind cannot be switched on when required, nor predicted much in advance, wind turbines almost always need to be connected with energy storage and/or other power plants. Such a combined system has basically only three control options:

1) Use wind power fully at all times and reduce output from other plants as necessary.
2) Invest in energy storage systems to absorb wind power at times of low demand.
3) Switch wind power off when demand is low or storage is full.

Electricity itself cannot usually be stored on a large enough scale. The only developed forms of energy storage which can be easily exchanged with electric power are hydraulic and electrochemical. Water can be pumped uphill to a reservoir, and Hydroelectric pumped storage is a well established scheme for meeting peak demand on a large scale, while a range of batteries and fuel cell derived systems can be applied in smaller units. If in the future hydrogen becomes established as a major means of energy transport, it may supersede all other forms of storage.