Cleantech Open runs the largest clean technology accelerator program in the world.

Applications for the 2023 accelerator program are now open. Apply by April 16th, 2023!


Technology Startups


Entrepreneurs Trained


Total Dollars Raised


and/or Women

Since 2005 Cleantech Open (CTO)  has trained over 3,500 entrepreneurs from 1,800 early-stage clean technology startups through its annual business accelerator. A majority of CTO alumni surveyed have survived the merciless technology startup “valley of death” and gone on to raise over $1.5 billion equity, and in recent cohorts, 39% of founder CEOs self-identified as BIPOC and/or women.

CTO’s one-of-a-kind innovation ecosystem built over the last decade and a half 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.

National Sponsors

Apart from the free survey software, we also have access to QuestionPro's free survey templates . We've found many of them useful and powerful to collect insights from various stakeholders of our organization.