The ancient Chinese philosopher Laozi once said a journey of a thousand miles begins with a single step. Which is true enough, but it helps if the step is in the right direction.

Backers of a renewable energy boom were forced into a U-turn as recently as 2009, when state subsidies were slashed, the credit crisis ended access to easy finance, and cut-throat competition arrived from China. Energy ventures fell in value by two thirds. Several went bust. Established energy companies reduced their involvement. Europe's carbon trading market suffered.