Cleantech Open
How to get into Cleantech Open according to the founders who did it
Our take
Best for early-stage cleantech, climate, hardware, or agtech founders who want a mini-MBA curriculum and strong mentors without giving up equity or waiting on a check. Skip it if you need capital on day one, you sell outside the U.S., or you are pre-product and want a roadmap built for your stage.
Acceptance
Broad, most applicants interviewed
Equity
None (unless you win)
Funding
Up to $50K (prize-based)
Duration
4–5 months
Stage
Idea to Seed
HQ
United States
We asked the founders how Cleantech Open really went.
Every interview behind this page is one we ran ourselves. The numbers, quotes, and lessons come straight from founders who went through Cleantech Open. No press releases, no PR gloss.
Who Cleantech Open is for, and who should skip it.
Best for
- You are building cleantech, climate tech, hardware, or agtech, the non-SaaS, slower-scaling companies conventional accelerators overlook
- You want a structured, mini-MBA curriculum and weekly mentor time without handing over equity or a slice of a cash check
- You will put in the work. The program is intense, weekly deliverables, and founders say you get out what you put in
- You are targeting the U.S. market and want investor days, a national pitch competition, and an alumni network to plug into
Skip it if
- You need capital on day one. Cleantech Open is a paid program, not a fund, and only the national winner gets a $50K check
- You are based outside the U.S. and selling outside the U.S. Founders from India, South Africa, and Canada found the curriculum U.S.-centric
- You are pre-product and want a tailored roadmap. The modules assume you already have something to test
- You want a hands-off, low-commitment program. The weekly cadence is demanding and falling behind hurts
What it's actually like at Cleantech Open
Cleantech Open runs a four-to-five-month program, summer through fall, built like a mini-MBA. Founders describe weekly modules across eight or nine themes (finance, market fit, sustainability, business model), each with worksheets, deliverables, and a pitch deck you build one section at a time. Weekly mentor check-ins anchor the whole thing. The word that comes up again and again is intense, and you cannot save the work for the end.
The program is structured around weekly meetings, each focusing on different key areas such as finance, market fit, and sustainability.
The application is not the gauntlet founders brace for. Most applicants get an interview with three or four Cleantech Open representatives who probe how you came to your idea, your grasp of the market, and how coachable you are. The stated goal is to graduate everyone, not to weed people out. Founders who walked in with a prototype, a proof of concept, or a grant application already written found the whole thing smooth.
CleanTech Open demands a significant amount of work and dedication, focusing intensely on growth and development.
The money, and what it actually costs
Here is the honest part. Cleantech Open does not hand you a check. It is a non-profit, it does not take equity, and it is a paid program. Founders pay an application fee and a program fee that, they were told, covers the cost of running the accelerator rather than turning a profit. Several offset it with outside grants. Joe Gelber's participation was covered by a New Jersey state grant, so his cost was effectively zero.
CleanTech does not take equity from participating startups, which was a major relief for us.
The money shows up as prizes, not investment. Winning at the regional level can be worth up to $5,000, and the grand national winner receives a $50,000 investment through a SAFE note, the one point where equity enters the picture. Renegade Plastics won nationals and took that SAFE. NTP Technologies won its region and the agriculture track and advanced to nationals. For everyone else, the value is the curriculum and the network, not the cash.
- Cleantech Open is a paid, non-profit program. You pay a fee, you keep your equity, and there is no investment on entry.
- Prizes are the only money in play, up to $5,000 regionally and a $50,000 SAFE note for the grand national winner.
- Founders routinely cover the fee with outside grants, which can make participation effectively free.
The mentors are the part founders keep
Ask what lasted, and founders point to the mentors and the network. Each company is paired with volunteer advisors, and the best matches change everything. Prateek Saxena credits a single Stanford-affiliated advisor with helping raise his next round and joining his board. For Marco Ma, the draw was sector expertise most programs cannot offer, help quantifying a company's real environmental impact. For Curran Hughes, it was a supportive, non-transactional relationship that outlived the cohort.
I attribute 99% of the value we gained from CleanTech Open to this connection.
The network extends past the cohort into investor days, a national showcase, and an alumni list that keeps sending opportunities years later. Mike Hermel pitched roughly half a dozen investors at the California open house. Joe Gelber met investors on both coasts. The recurring caveat is that the whole thing is built for the U.S. Founders from India, South Africa, and Canada valued the foundation but had to adapt the U.S.-centric playbook to their own markets.
CleanTech Open presented itself as a mini MBA, and the fees were justified as an investment in exclusive mentorship.
The founders we talked to.
Alumni include Princeton NuEnergy, BlocPower, Flux Marine, Renew CO2, PolyGone Systems.
Want the mentorship without the accelerator?
An accelerator's real value is the people who have done it before. GrowthMentor gives you that on its own. Unlimited 1:1 calls with founders and operators, from $50 a month, no equity, no application, no relocating. You will not get a cohort or a national pitch prize, but if what you're really after is a mentor who has built a hardware company or cracked a market you're chasing, you can start those conversations today.
RecommendedFormat
Live 1:1 calls, on demand- Cleantech Open
- 4–5 month cohort accelerator, regional + national
Cost to you
$50–$150/month, no equity- Cleantech Open
- Program fee (non-profit), no equity taken
Capital
None. It's mentorship, not funding- Cleantech Open
- None on entry, up to $50K prize for the national winner
Commitment
As much or as little as you want- Cleantech Open
- Part-time but intense, weekly modules and deliverables
Acceptance
Open to any member- Cleantech Open
- Broad, most applicants get an interview
Best for
Founders wanting targeted advice from operators who've done it- Cleantech Open
- Early cleantech and climate-tech founders wanting curriculum + mentors
Relationship
Pick your mentor, book again whenever you need- Cleantech Open
- Cohort + alumni network, mentor-led
From $50 a month · no equity.
Questions founders ask about Cleantech Open.
No, with one exception. Cleantech Open is a non-profit, and participation costs a program fee rather than a slice of your company. The only time equity enters is if you win the national pitch competition, where the grand prize is a $50,000 investment through a SAFE note. Regional winners can take up to $5,000. Founders like Curran Hughes of Renegade Plastics singled out the no-equity model as the reason they chose it over other accelerators.
It is a paid program. You pay an application fee and a program fee that, founders were told, covers the cost of running the accelerator rather than generating profit. There is no investment on entry. Several founders offset the fee entirely with outside grants; Joe Gelber's was covered by a New Jersey state grant. The money on the table comes through prize competitions, not a check for joining.
Roughly four to five months, summer through fall, structured like a mini-MBA. Founders describe weekly modules across eight or nine themes (finance, market fit, sustainability, business model) with worksheets, deliverables, and weekly mentor check-ins. Nearly everyone called it intense and warned against letting the work pile up.
The mentors and the network. Companies are paired with volunteer advisors, and a strong match can change everything. Prateek Saxena of Hygge Energy credits one advisor with 99% of the value he got from the program. Beyond mentorship, founders valued investor days, the national showcase, and an alumni network that keeps sending opportunities years later.
The foundation travels, but the specifics do not. Founders from India, South Africa, and Canada all said the curriculum is heavily oriented toward the U.S. market and how venture funding works there. They still recommended it for the business fundamentals and mentorship, with one caveat. If your market is elsewhere, budget for travel and be ready to adapt the playbook.
