Cleantech Open 2025 Berkeley + East Bay Kick-Off Event

Join us as we launch our 2025 Cleantech Open program in the East Bay!

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!

New Energy Nexus is a global organization with many chapters worldwide. NEX California is one of two in the US. Collectively, our vision is 100% clean energy for 100% of the world, and we’re all united under the mission to build a more inclusive clean energy ecosystem.

, a New Energy Nexus Program
CalSEED supports early-stage entrepreneurs developing clean energy technologies focusing on energy equity for California's vulnerable populations. The program offers up to $700,000 in grants, professional development, and access to accelerators to ready concepts for investment and deployment.

• Direct, non-dilutive grant-based funding to advance clean energy innovations to commercialization ($200K for Concept Awards and a $500K Prototype Award to winners of the annual Business Plan Competition).
• Access to Cleantech Open and a network of Regional Energy Innovations Clusters.
• Targeted professional development services, including mentorship with seasoned professionals, legal counsel, expert guidance, and training to support technology refinements, market development, and commercialization.

, a New Energy Nexus Program
A laboratory voucher and commercialization development program for innovators and entrepreneurs working to bring early to mid-stage clean energy concepts to market, made possible by a grant from the California Energy Commission (CEC) Electric Program Investment Charge (EPIC).

• Testing vouchers worth up to $300,000 for use at one of 70+ world-class testing facilities.
• Exposure to a broader clean energy ecosystem, additional funding opportunities through and access to the New Energy Nexus community and global network.
• A network of industry experts, investors, prospective partners, and utilities, and opportunities to present to customer groups and commercialization partners.

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: Ryan Hoover, Director of Operations - Cleantech Open West

Event Venue & Nearby Stays

Brower Center, 2150 Allston Way, Berkeley, United States