Venture capital investment in green-tech companies topped $5 billion in North America and Europe last year and shows no signs of slowing down.
The Cleantech Group on Thursday published results of its quarterly numbers that show investment in the sector was stronger than expected.
Investment leaped from $3.6 billion in 2006 to $5.18 billion in 2007.
Energy generation was the most active sector with 172 deals, totaling $2.75 billion.
Behind that was energy storage at $471 million, transportation at $445 million, energy efficiency at $356 million, and recycling and waste with $291 million.
Cleantech Group said that the number of deals over $100 million increased, which it saw as an indication of growing investor confidence.
The conditions for the influx of money to energy and environmental start-ups--high fossil fuel energy prices and favorable policies--will remain, which means that 2008 will likely see the same pace, said Nicholas Parker, chairman of Cleantech Group.
"We foresee continued growth over 2008 as the clean-tech market cycle moves from early adoption to mainstream driver of wealth and job creation," he said in a statement.
Here's a historical view of clean-tech investment, according to Cleantech Group:
2007: $5.18 billion
2006: $3.6 billion
2005: $2.5 billion
2004: $1.8 billion
2003: $1.7 billion
2002: $899 million
2001: $714 million