If you have any questions, please check out our application FAQs here.


We are the cleantech experts.
We find, fund, and foster the most promising cleantech startups on the planet.

Cleantech Open is a global accelerator for early-stage clean technology startup companies. We run an annual six-month program to connect startups with the people, resources, and visibility to help them succeed.

Since 2005, the Cleantech Open has awarded over $6 million in cash and services to cleantech startups. The 1000+ companies in the Cleantech Open's Accelerator Programs have raised more than $1.1 billion in external capital.

The US Cleantech Accelerator Program


Accepted applicants to the program work with mentors, access a valuable network of professionals, and attend business clinics and webinars that provide them with the skills they need to take their business forward. In the fall, teams present their ideas for regional-level judging and are awarded prizes on the regional level. Finalist teams from regions across the county move on to be showcased in our annual Global Forum. The Global Forum showcase also features a competition among the regional winners where national prizes are awarded. If you are interested in applying to the accelerator program, please get started here.

Volunteers and Mentors

As a non-profit organization with a small full-time staff, the Cleantech Open is run largely by volunteers. Our volunteers are united in their passion for clean technology and helping to make a difference in the world. If you are interested in volunteering or mentoring a team, please get started here.

Our Global Programs

If you are a non-US based entrepreneur, you are eligible to participate in two programs.

The Global Ideas Competition

The Cleantech Open is looking for the best clean technology ideas from around the world. If you are a finalist from your country, your idea will be presented in a three-minute pitch in front of a crowd of 1,000 investors, entrepreneurs, sponsoring companies, corporations, members of academia, press, and others interested in hearing your ideas and getting involved.

A judging panel of cleantech experts, investors and entrepreneurs will select the winning team. You could win marketing support, legal advising, conferencing services and more to help launch your business! Get started here.

The Global Cleantech Innovation Programme

This program is focused on enhancing both emerging cleantech startups in each country and the local entrepreneurial ecosystem and policy framework. We use a competition-based approach to identify the most promising entrepreneurs across a country, while a local accelerator supports, promotes and “de-risks” the participating companies and connects them to potential investors, customers and partners.

The very best startups from each country are brought together in Silicon Valley, California, where they can both compete for the Global Prize and connect with potential partners, customers and investors from around the world. Learn more here.