Venture money in green companies off 33 per cent

Green technology venture investment, however, was supported by increasing corporate and utility investment, the group said.

Investment in solar in 2009 was down 64 percent from the previous year, but the sector continued to be top green technology sector for venture investment in 2009 and accounted for 21 percent, or $1.2 billion, of total green investment.

Companies in the green transportation sector attracted $1.1 billion while the energy efficiency sector saw $1 billion in venture investment.

Deloitte and Cleantech Group also reported that there were an estimated 505 clean technology mergers and acquisition transactions last year, totaling $31.8 billion, and clean technology public offerings totaled an estimated $4.7 billion in 32 offerings.

"Most of the IPOs took place in Asia, especially China," said Dallas Kachan, managing director of Cleantech Group.

"Couple this with aggressive clean technology spending by China and South Korea, and record levels of patent registration in Japan, and it's clear 2009 was the year Asia made significant inroads on its Cleantech ambitions," he said.

The top three most active green venture investors in 2009 were Kleiner Perkins Caufield & Byers, SAIL Venture Partners and RockPort Capital Partners.