Wind energy is unreliable and provides only an irregular source of supply – and even then only in some countries  Wind will only ever be a useful additional technology to provide extra capacity at time of high demand. We know it to be both unreliable and unpredictable. We know that unreliable technologies are fraught with expensive difficulties. As a result relying on such a technology would be reckless.  To take one example, the only way of building in a capacity for wind into a regular energy network would require the construction of ‘battery capacity’ such as hydro-power. Developing such a capacity would be both hugely expensive and unreliable – it’s useful if the wind fails to blow for a few hours, if the doldrums last for a few days, then everything grinds to a halt.