But the tube is already badly overcrowded at peak hours and can only get worse in the near term.

ECONOMIST: London's roads

The problems include no signal, people only being able to make calls during off-peak hours and voicemail failing to save and record messages properly.

BBC: Anger over 'poor' Vodafone mobile network in Marlborough

He dreams of building gigawatt-size plants, of shipping solar thermal power to the cloudy Northeast and of using molten salt to store energy so thermal plants can power homes at night. (Nevada Solar One is only for daytime peak loads.) He envisions mirrors in space that can soak up sunlight 24 hours a day.

FORBES: Light And Heat