The rapid growth of wind power has turned the business of transmission and distribution on its head. Gone are the guiding principles of the past 50 years. The market incentives of the old days are working against the investment in new wires needed today. Britain and America share the same dilemma: should transmission lines be built in the expectation that generators will turn up to use them? Or should generation be built in the expectation that new wires will follow? There is a third way. And it is perhaps no coincidence that national regulators in both countries are moving towards it.