Reflections from Our Summer 2026 Fellows

Luis Antillon

I joined Clean Energy Ventures to learn the ways early-stage tough tech companies navigate the missing middle, the frameworks VCs use to find conviction, and the solutions founders are identifying to accelerate the world's energy transition. Through this lens, my summer fellowship was nothing short of ideal. The firm's culture is highly collaborative and unusually flat: while the team was excited to mentor the summer fellows, they also valued our perspectives and very quickly entrusted us with high-value work.

Alongside pipeline diligence of over 15 companies, I led the business model workstream from initial call to closing deal terms for a battery storage startup with a novel approach for the C&I market. Regular meetings, including time with the CEO to discuss his long-term vision, showed me a company working to improve access to cheap, reliable power across the US. I realize now that an innovative idea is just the start. What makes a startup successful is how well the business model fits the market, and the team pulling the vision together.

I also learned a ton about VC firm operations: in partnership with the firm's COO, I expanded on CEV's AI strategy and shipped several automated workflows to deepen the team's diligence capabilities. I launched a company survey to identify drivers of painful, low-value work and to surface the right solutions.

From seeking climate opportunities in the quantum computing space to touring startup R&D facilities to sailing around Boston Harbor on our company onsite, my summer with CEV was exciting, informative, and a lot of fun. I leave the fellowship empowered to contribute to early-stage technical companies as both an operator and an investor. Thank you to the entire CEV team for a great summer, with a special thanks to Lou Schick, Ted Dillon, Matt Cohen, Wynston Reed, and Cooper Bates for the mentorship and deep chats.

Mariana Perez-Gavilan

I came to CEV with the intention of learning about what it really takes to make impact investments. Being a Summer Fellow has truly shown me the importance of early-stage capital to address the climate crisis: there are people with amazing and innovative ideas and are working towards developing them. What they need is the right kind of support to commercialize these solutions. I've reaffirmed my idea that in order for climate solutions to scale, they need to make sense as businesses, and for this to happen, entrepreneurs need guidance, support, and capital. I've also learned the importance of teams: the people leading these revolutionary ideas are just as important, or even more so, as the ideas and technologies themselves.

I was fortunate to work on two active diligence processes. For the first company, I focused mainly on analyzing the market, specifically the revenue opportunities of battery energy storage systems (BESS), and how those have evolved over time. Not only was I able to dive deep into the data, but I was also challenged to give my opinion on where the market was going next. This ended up being very impactful when deciding whether to invest or not, which was extremely gratifying. During the second diligence process, I was able to be involved in a wider range of topics, thinking through the technology differentiation, business model viability, exit potential and possibilities, and whether the market was attractive, and big enough to generate a venture return. Having the opportunity to analyze a company holistically was extremely educational and enriching.

Most of all, I'm grateful for possibility of working with an amazing team within CEV. They taught me by example how to work as a team, lean on each other, ask tough questions, and bring my passion for climate change to work every day. I leave with many learnings, but also many new friends and mentors I hope to carry with me through the rest of my professional career.

Grace Memmo

I joined Clean Energy Ventures this summer through the ICM Mosaic Fellowship, excited to better understand the investor side of the climate tech ecosystem. Before business school, I worked across engineering, operations, and commercial roles at Dow and Syzygy Plasmonics. During business school, I became increasingly interested in how emerging climate technologies are evaluated, which companies have the potential to scale, and how investors can support them along the way. CEV gave me the opportunity to immerse myself in those questions and gain firsthand exposure to early-stage climate investing.

One of my biggest takeaways from the summer was how many different ways an investor can engage with a problem or company. I developed an investment thesis around grid interconnection and flexibility, which required digging into a complex and rapidly evolving part of the energy system and forming a perspective on where startups can create meaningful value. At the same time, supporting diligence on a geothermal startup that progressed to an investment committee meeting showed me how that type of research and questioning gets applied to an actual investment decision. On the portfolio side, working with a water purification company to evaluate a new market opportunity gave me a different perspective on the role an investor can play after the check is written. Through CEVG, I also had the opportunity to join screening discussions and founder pitches alongside experienced operators and angel investors, which reinforced how differently people can look at the same opportunity depending on the expertise and pattern recognition they bring to the table.

The fellowship expanded my view of just how broad climate tech is. Between the companies we evaluated, portfolio company site visits, and hearing team members present their investment theses weekly, I was exposed to technologies and markets far beyond the areas I knew coming into the summer. I was struck not only by CEV's ability to go genuinely deep across an enormous range of technical domains, but also by how collaborative that expertise is in practice. People constantly bring their own experience to each other's thinking, supporting ideas while also pressure-testing assumptions and making sure problems are considered from multiple angles. I'm leaving CEV with a much broader understanding of climate technology and early-stage investing. I'm especially grateful to Amy for her guidance, feedback, and support throughout the summer, and to the broader CEV team for how generously they shared their expertise and included me in the process.

Eli Cooper

The through-line of my summer at CEV was learning what it takes to build an investment thesis you can stand behind. Venture bets are unconventional and revolutionary in nature, and I found myself often asking "but what if it works?" or "what's the theory of change we need to believe?" Asking the right questions is often more important than finding a historical source of truth.

What I enjoyed most was the balance of autonomy and support the team gave me. I was trusted to run an electrified industrial heat analysis, fairly independently. The team was consistently generous with their time to stress-test my thinking, propose areas for further diligence, and push me towards sharper conclusions. That combination taught me about the importance of the team, and how to collaboratively operate as an investor.

The clearest lesson I'm taking with me is that building conviction in a market and management team can often supersede any technology innovation. Industry pull paired with management's ability to fundraise and recruit are essential to believe the transition from what's proven to what's possible. It's reshaped how I think about climate tech and venture more broadly. A market thesis can hinge on a handful of variables, and an investment decision ultimately rests on the credibility of the people behind the technology as much as the technology itself. I'm leaving this fellowship grateful for my colleagues that modeled that rigor for me, and feel encouraged to carry it forward into my future opportunities.

Jake Brenner

I came to Clean Energy Ventures with a clear goal: to understand how climate tech venture capital maximizes impact and helps bring innovative solutions to market. I met that goal quickly, seeing firsthand how impact holds equal footing with returns in the CEV diligence process.

Over the summer I developed a thesis on whether climate adaptation, and weather intelligence in particular, could yield venture-scale returns while satisfying CEV's strong impact requirements. Given the clear need for venture investment in adaptation solutions across sectors and geographies, the challenge was identifying where the traditional venture concerns of durability, scalability, and returns overlap with meaningful improvement in adaptation capability. I built the thesis out by speaking with adaptation experts and practitioners, creating a market map of the weather intelligence space, and devising a screening rubric that scores adaptation companies on impact and venture-scale potential together.

The most exciting piece, however, were the two live diligence processes I supported. These let me pressure-test the thesis on real companies and learn how the playbook of climate-tech venture diligence could be applied to adaptation. I learned how players in the weather intelligence space may need to differentiate on novel weather data collection and integrate with operational decision making to compete as free public data and big-tech weather models keep getting better. I also learned that the strongest opportunities sit where adaptation value and emissions reduction overlap, the clearest place where venture returns and CEV's impact bar line up.

This experience of developing a thesis and employing it through sourcing and diligence was made possible by the CEV team. While fellows on paper, the team viewed us as full members of the investment team, with the agency to share opinions, support diligence decisions, and inform fund direction. As my manager, Yi Jean gave me real ownership along with steady guidance to refine my venture investor toolkit and advance CEV's thinking in the adaptation space. I'm leaving with a much clearer picture of how early-stage climate investors actually drive impact, and am more certain than when I arrived that this work aligns with the type of impact I'm looking for in my career. I look forward to my next opportunity to direct capital toward climate technologies and solutions, and know I will stay close to the CEV team as I do so.