Clean Edge just published their annual report on clean energy trends. The trends are upward:

According to Clean Edge research, biofuels (global manufacturing and wholesale pricing of ethanol and biodiesel) will grow from $15.7 billion in 2005 to $52.5 billion by 2015. Wind power (new installation capital costs) will expand from $11.8 billion in 2005 to $48.5 billion in 2015. Solar photovoltaics (including modules, system components, and installation) will grow from an $11.2 billion industry in 2005 to $51.1 billion by 2015. And the fuel cell and distributed hydrogen market will grow from $1.2 billion (primarily for research contracts and demonstration and test units) last year to $15.1 billion by 2015.

In total, we project these four clean-energy technologies, which equaled $40 billion in 2005, to grow fourfold to $167 billion within the coming decade.