The world’s oldest and largest
cleantech startup accelerator.
Bringing early-stage cleantech acceleration
to emerging economies.
Since 2005 Cleantech Open (CTO) has trained over 1200 early-stage clean technology startup entrepreneurs through its annual business accelerator. A majority of CTO alumni have survived the merciless technology startup "valley of death" and gone on to raise $1.2 billion and create over 3,000 clean economy jobs.
CTO's one-of-a-kind innovation ecosystem built over the last 11 years of programming spans key cleantech innovation hubs in the U.S. and globally. As a non-profit organization run largely by volunteers, there are many ways to contribute. Join our global network of innovation and together let's forge a clean and sustainable future.