Cleantech Open 2025 San Francisco Kick-Off Event

Join us as we launch our 2025 Cleantech Open program in San Francisco!

Cleantech Open (CTO) is the world's oldest and largest Clean Technology Startup Accelerator. Nearly 2,100 early stage cleantech startups successfully graduated our program since 2005.  This year, we celebrate 20 years of early-stage cleantech startup support!

Calling Startups!

We are looking for ambitious, innovative entrepreneurs working to solve some of the world's greatest environmental and economic challenges across 8 broad industry domains: energy generation, energy distribution, energy efficiency, green building, transportation, chemicals & advanced materials, agriculture/water/waste, information & communication technologies.

Our curriculum has evolved over 20 years into a well-honed 12-week program starting in June and running through August, with a final competition in September and Culminating Event in October. By the time you're through CTO, you'll have everything you need to pitch to early-stage investors and Climate VCs. 

Each startup works through the program with at least one assigned mentor, who guides the startup through the curriculum, offering perspective and feedback.  Our mentors are seasoned professionals with startup, corporate, and industry expertise.  

Through Cleantech Open, startups gain access to the burgeoning cleantech startup support ecosystem here in California, across the US, and across the globe.  Our partners include government programs, corporate innovation offices, investors, professional organizations (e.g. legal, finance, accounting), and NGOs.  

We work with startups that have raised <$2M in equity, all the way down to trying to flush out an idea on the back of a napkin. If you're serious about your business, then we are here to help!

Calling participants in the Cleantech Startup support ecosystem!

We are always working to expand our Cleantech Open network in San Francisco and the broader Bay Area.  Our network includes mentors, partners, and volunteers.  We are a mission-focused, volunteer-driven non-profit organization that works to find, fund and foster the startups and technologies that will address the largest environmental and economic challenges we face as a society.  Whether you are a seasoned professional or just starting your career, we welcome you to join our community.

Join us!

At our launch event, you’ll get the chance to share your idea/company with the audience, and to meet CTO alumni, mentors, partners, volunteers and staff.

All are welcome!

We'll have some light food available as well!

NOTE: About $10 Quality Assurance RSVP fee: All CTO Events have a $10 Quality Assurance RSVP fee to discourage no-shows and encourage maximum engagement. If cost is an issue, please contact Ryan Hoover at [email protected] and we can work something out.

Info: Either a speaker or a fireside chat (TBA).

Host or Publisher Cleantech Open