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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.

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 $300-$400k 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.


Aaron Fyke

Founder and Managing Partner

Aaron Fyke has spent over twenty 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, bringing investment capital to bear on some of the world’s toughest problems in energy, water and food sustainability.  


While CEO of Heliogen, he was committed to lowering the costs of solar thermal power.  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 - backed by Idealab, Bill Gates, NRG, and others.  Aaron continued his work with gravity storage with Energy Vault, which received a significant investment from SoftBank.


Previously he headed up the development of a $10M X PRIZE in Energy for the X PRIZE 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 has been an adjunct lecturer on entrepreneurship at USC and a consultant and keynote speaker to utilities (e.g., TransAlta), corporations (e.g., Google) and a number of conference and media events (MIT Tech Review, AlwaysOn Going Green and others).


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. 


Eric Manlunas is the co-Founder and Managing Partner of Wavemaker Partners, an early-stage cross border venture capital firm dual headquartered in Los Angeles and Singapore with over $350M of assets under management. Eric started Wavemaker’s predecessor firm, Frontera Group, a prior early-stage boutique venture capital firm he founded in 2003.  Eric has a proven track record as an early investor in over 300 early-stage businesses.  Prior to becoming a venture capitalist, Eric founded two technology start-ups, one in e-Commerce in 1996 and the other in Internet services in 1999, both of which were successfully built and eventually sold to strategic buyers.  He earned an MBA from Pepperdine University in 1995 and an undergraduate degree in Communications from Florida International University in 1990.

Eric Manlunas





Sistine Solar transforms any traditional solar panel into one that blends in with a roof, no matter what color, style, or pattern. Using design and aesthetics, Sistine helps homes and businesses to go solar with style.


Kevala makes energy related data meaningful, transparent and accessible.  Utilities and regulators trust Kevala to provide analytics to accelerate smart investment in a more robust and environmentally sustainable electricity grid.


Voltaiq’s software platform dramatically accelerates battery innovation by providing compre-hensive, interactive, battery-specific data management and analytics tools, valuable across the entire battery supply chain. 

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