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We at Thin Line Capital are entrepreneurs, like you.  We have started six climate-tech companies, including two unicorns.  We understand and applaud the dedication of anyone who does what it takes to succeed.  Success isn’t cheap, nor is it easy.  We are your partner, we understand the struggle, and are excited to work with entrepreneurs who play to win.

We are firm supporters of ethical conduct in the entrepreneurial community and in everything we do, therefore we are proud signatories of VC Lab's Mensarius Oath.


Decarbonizing the global economy is the biggest economic opportunity since the Industrial Revolution.

With trillion-dollar opportunities available, we are here to help build the next wave of world leading companies.


Explosive Growth
in Renewable Energy

Renewable energy has an annual growth rate of ~17% on an enormous installed base of over 2000 GW. 

In 2019, solar and wind provided the cheapest sources of new electricity for two-thirds of the world.


Revolutionary Adoption
of Electrified Transportation

The EV market has been growing at roughly 60%/year since 2015. 

With a $53 trillion market opportunity between now and 2050, there will be huge winners as the automotive industry reinvents itself.


The World Will Decarbonize
Our Built Environment

One tonne of cement produces one tonne of CO2.
One tonne of steel produces 1.8 tonnes of CO2.


Software and data analytics tools that can improve logistics, lower manufacturing costs, and cut construction waste will find staggering market demand.


Demand for Climate Resiliency
Solutions is Here

Natural disaster losses globally reached $330B in 2017,
up from ~$50B/yr in the 1980s. 


Increased sensing tools, predictive analytics, and iOT solutions can help industries adapt to an expected $100B+ annual losses due to the effects of climate change.

About us


We are experienced entrepreneurs with strong market knowledge of what’s required to succeed in energy/sustainability industries. ​We have deep technical and engineering knowledge and the ability to mentor and guide founding teams. We are passionate about entrepreneurs and want to be your first and last resource as we share the journey with you. 


Focused Investment Thesis

Invest $400-$600k into seed stage, low-capex companies targeting the booming verticals of renewable energy, electrification of transport and climate resiliency.


Invest in What We Know

Invest in companies we have deep domain experience in, and then play an active role as a partner supporting the founders to drive success.


Concentrated Portfolio

This is not a scattershot.  We intend to build a portfolio with select companies in order to focus more resources on what it takes to succeed.


Active Investor

As prior entrepreneurs, we know the value of a shared journey.  We are passionate supporters of our companies, acting as advisors and mentors.

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Aaron Fyke

Founder and Managing Partner

Aaron Fyke has spent thirty years as an investor, engineer, and entrepreneur, having cofounded six companies, including two unicorns, in a number of technology areas including fuel cell, ocean power, concentrating solar, and grid-scale energy storage.

He is currently Founder and Managing Partner of Thin Line Capital.  Thin Line Capital is now deploying their second fund to bring investment capital to extraordinary clean energy/climate change companies, participating in the biggest economic opportunity since the Industrial Revolution.

While CEO of Heliogen, his first unicorn, he was committed to lowering the costs of solar thermal power, backed by Idealab, Bill Gates, NRG, and others.  Prior to Heliogen, Aaron was the Founder and CEO of Energy Cache, a low-cost grid scale energy storage technology company, serving a multi-billion dollar energy market.  Aaron continued his work with gravity storage with Energy Vault, which ultimately listed as his second unicorn.

He currently serves on the investment committee for USC's Viterbi Venture Fund.  Previously, he headed up the development of a $10M XPRIZE in Energy for the XPRIZE Foundation.  Prior to that he was a Partner at Starfish Ventures, Australia’s largest venture capital firm, where Aaron led the investment into the fund’s biggest investment and exit.

Aaron earned his MBA and MSME as an LGO fellow at MIT, and his BEng in Mechanical Engineering from the University of Victoria, graduating at the top of his class.  He has been certified as a Professional Engineer both in California and British Columbia. 


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"Max" Nikias

President Emeritus

University of Southern California


Founding Director of the Integrated Media Systems Center, Professor of Electrical Engineering, Director of Synopsys, an S&P 500 semiconductor manufacturer, member of the National Academy of Engineering.

Andy Wilson

Executive Director

Alliance for SoCal Innovation


As a serial entrepreneur, Andy has led, founded, or invested in almost two dozen technology startups. Previous Vice Mayor of Pasadena, and a co-founder of Innovate Pasadena.

Eric Manlunas

Founder and Managing Partner

Wavemaker Partners


Eric is a two-time startup entrepreneur with a proven track record as an early investor in over 300 early-stage companies in the US and Southeast Asia.

Carl Sheldon

Managing Partner

Bellnote Partners


Prior CEO of the Abu Dhabi National Energy Company (TAQA), and Managing Partner of Allen & Overy LLP's Frankfurt and New York offices during his 25 year tenure.

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