Bullet Energy Solutions is on a mission to make it easier to switch to an electric car. Its goal: to become the leading installer of EV chargers and infrastructure coast to coast.
"My motivation for taking environmental classes came from a deep desire to understand the industry I was about to enter. While I explored many types of entrepreneurship courses, I felt uniquely positioned to build a venture that could deliver meaningful environmental outcomes."
- Tara Rezapour '25
The Austin, Texas-based company got its start after Allen Rezapour, the firm’s CEO, sold his company, Fox Rent A Car, to European car rental Goliath Europcar in 2019. Over 35 years prior to the acquisition, he and two partners built Fox into the largest independent car rental company in the United States.
At the time of the sale, Allen, an electronics engineer by training, was looking for a way to use what he had learned in the car rental business to help the environment. He also wanted to create a business that his children could run someday. Following in her father’s footsteps, his daughter Tara Rezapour ’25 entered Columbia Business School through the J-Term MBA, a 16-month option heavily attended by students with a family business background.
Allen teamed up with Andres Pinter ’03 and Mark Vogel, a partner and veteran solar industry executive who had worked in the renewables space since 2013. Eager to capitalize on the EV charging boom, the trio founded the company in 2022 (Pinter became a senior managing director at a business consultancy in late 2024).
To generate revenue in its early days, Bullet focused on installing solar panels and battery storage systems for residential customers. Meanwhile, its team conducted feasibility and competition studies for the EV installations it planned for the future. “Allen and I probably spent six months doing due diligence prior to even starting the company,” recalls Vogel, COO.
Through Vogel’s industry relationships, Bullet partnered with a third-party company that had secured master service agreements with most of the major automakers manufacturing EVs. When customers purchased one of their vehicles, Bullet had the opportunity to bid on the installation of the charging stations.
The business took off quickly, and the company now installs both residential EV chargers and commercial EV superchargers. Bullet plans to expand nationally after establishing a presence in Arizona, California, and Colorado. With 42 employees, it now projects about $10 million in revenue for 2025 and just posted its first profitable quarter in Q1. “It’s a huge milestone for us,” says Vogel.
Meanwhile, Tara powers the company’s business development as head of marketing, tapping what she learned at CBS about scaling a sustainable business. She was very involved in the School’s Family Business Club and took family business courses with professors such as Senior Lecturer Gaia Marchisio along with environmental classes.
“My motivation for taking environmental classes came from a deep desire to understand the industry I was about to enter,” she says. “While I explored many types of entrepreneurship courses, I felt uniquely positioned to build a venture that could deliver meaningful environmental outcomes.”
Bullet is mostly self-funded for now, but an early sign of its potential to attract interest from investors came when Tara’s classmate Pedro Pablo Scarpetta ’24 pitched it in CBS’s Investing in Social Ventures class in fall 2023 and won. That paved the way for the company to receive funding through the Tamer Fund for Social Ventures (TFSV) at the Tamer Institute for Social Enterprise and Climate Change. The TFSV provides seed grants to nonprofit, for-profit, and hybrid early-stage Columbia University-affiliated social and environmental ventures. (Application deadlines are March 1 and August 15.)
These days, Bullet is working to differentiate itself with its data systems.
“We prioritize having complete dashboards daily—tracking labor, fuel usage, product purchases, and every critical detail,” says Allen. “Building a data-driven culture from the start is key to scaling and running a business effectively.”
Climate Innovators Make Their Mark
Bullet Energy Solutions reflects the new wave of climate innovation startups emerging from the CBS community and beyond—ventures grounded in strong business fundamentals and built for scale. As the demand for clean, reliable infrastructure grows, and the urgency around climate solutions intensifies, student-and alumni-run companies like Bullet are turning bold ideas into operational reality.
And that is by design. CBS now prepares all its business school students to think about climate and consider a career built around climate innovation, whether as entrepreneurs, investors, or policy leaders. However, even if they don’t pursue a career that is directly related, they will be well-versed on climate considerations and able to bring that to whatever work they choose to do.
Over the next several decades, the impacts of climate change will be felt by nearly every business everywhere on this planet,” said Bruce Usher, the Elizabeth B. Strickler ’86 and Mark T. Gallogly ’86 faculty director at the School’s Tamer Institute for Social Enterprise and Climate Change, speaking at the annual Tamer Institute Awards Breakfast, held this year on Earth Day. “This means the opportunities for businesses to create value by tackling climate change are vast, disruptive, and growing.”
Against that backdrop, learning how to maximize returns and minimize threats will be essential, according to Usher. “Climate change creates new and growing risks that will separate the best-run companies from the rest,” he said.
Despite a reversal of policy support in Washington, DC, more corporate decisions to deemphasize net-zero pledges, and a pullback by investors in climate tech, Usher said Columbia does not plan to scale back its commitment to climate innovation, viewing it as a long-term strategy. “We teach skills not just for the next four years but for the next four decades,” he said.
The Tamer Institute plays a crucial role in supporting that commitment. Its programs empower students with the business knowledge and skills in entrepreneurship and management they need to find creative new solutions to social and environmental challenges.
Tamer Institute Fuels Climate Startups
The TFSV has backed a variety of climate-tech startups from the university community, some of which also tap into the resources of the Eugene M. Lang Entrepreneurship Center.
“Over the past decade, the Tamer Fund for Social Ventures has supported 29 climate and sustainability-focused ventures spanning sectors like clean energy, circular economy, sustainable agriculture, water innovation, and climate finance,” noted Usher, who serves as chair of the Tamer Fund. “Making up about half of the fund’s portfolio, these ventures demonstrate how Columbia-affiliated founders are driving real-world impact.”
Usher pointed to Kheyti, a startup that has developed a greenhouse-in-a-box solution that is helping small farmers in India reduce climate risk and increase crop yields. Co-founded by Kaushik Kappagantulu ’17 and backed by the Tamer Fund in 2016, the company received the 2022 Earthshot Prize for Protect and Restore Nature from His Royal Highness Prince William, The Prince of Wales, and the U.K. Royal Family Foundation. The company aims to reach 50,000 small farmers by 2027.
Among other promising ventures backed by the Tamer Fund are:
- Plentify, a provider of smart energy solutions, including a smart solar water heating service aimed at clients in African cities, founded by Jon Kornik ’11.
- Sortile, which has brought a technology to the textile industry that enables the identification, sorting, and traceability of textiles. Founders Constanza Gomez ’22 and Agustina Mir, SIPA’21, met while studying at Columbia.
- Tough Leaf, a climate-adjacent startup that connects construction contractors, including those working on climate-resilient projects, with minority-owned and small businesses to foster more equitable contracting. Wissam Akra ’22 received funding from the Tamer Fund and won the 2025 Tamer Alumni Innovator Award.
On campus, the Tamer Fund has catalyzed a culture of climate entrepreneurship, encouraging students and alumni to develop scalable solutions and innovations in climate investing as well. There has been an overall increase in applications related to climate over the past four to five years, including AI-native startups such as Giraffe Bio, which developed an AI-powered method of metal extraction, and Terralytiq, a decarbonization partner for large supply chains.
All these startups are part of an international business ecosystem of companies that prioritize climate innovation, one that also includes the larger, scalable companies CBS is preparing leaders to build and run. The Tamer Institute helps students enter that world equipped with a clear grasp of climate-related issues by supporting new ideas from both faculty and industry leaders as well as innovative curricula like the Investing in Social Ventures Course and extracurricular activities for students.
One example is the Tamer Institute’s Three Cairns Fellowship, endowed by Elizabeth Strickler ’86 and Mark Gallogly ’86 from the mission-driven investment and philanthropic firm Three Cairns Group. The fellowship offers support to MBA and Executive MBA students who complete semester-or year-long projects at the intersection of climate change and business. Students often pursue projects while working with Columbia researchers or outside companies and organizations that address sustainability and climate change.
The Tamer Institute has made careers in climate innovation and social entrepreneurship more feasible for many students by providing additional funding to the Loan Assistance Program, which alleviates the burden of student loan repayment for students pursuing careers in public service and the nonprofit sector. The program was made possible by a gift from the Class of 2005, and originated from the Guenther Family Public and Nonprofit Assistance Grant, a program established in 1998 that awarded post-graduation grants to MBAs entering the public and nonprofit sectors. The institute has expanded the availability of the Social and Environmental Summer Fellowship to Columbia students outside of CBS, funded social ventures at the Columbia Startup Lab, and contributed to the development of Columbia’s advisory network for social entrepreneurs.
The founding of the Tamer Institute and the recent expansion of its programs embody a long, university-wide commitment to social ventures and climate change. In 1981, Ray Horton, Frank R. Lautenberg Professor Emeritus of Ethics and Corporate Governance, established the Public and Nonprofit Management Program, renamed the Social Enterprise Program in 2000, to broaden understanding of how business can contribute to society and the environment. It has since expanded its focus to social entrepreneurship, corporate social responsibility, and international development.
Pioneering Innovation in Teaching and Research
Another key driver of climate innovation is a unique curriculum designed to help students integrate sustainability into all their business activities.
Over the past decade, the climate-related course offerings at CBS have grown from only two disconnected electives with limited offerings to more than 10 courses, many with wait-lists. This significant increase in climate-related courses has been driven in part by intense student demand as well as the leadership and vision of CBS Dean Costis Maglaras. In 2019, when Maglaras became dean, he made climate and sustainability a core pillar around which to focus future CBS research and teaching.
CBS’s Business and Climate Change course, taught by Usher and Gernot Wagner, a climate economist and faculty director of CBS’s Climate Knowledge Initiative, signaled there was even more interest in climate innovation on campus than they originally thought: More than 500 students enrolled, and it was taught in eight sections. As part of the recently launched CBS Curriculum Pathway focused on climate, students can also take four more deep-dive electives: Climate Finance, Climate Tech, Climate Policy, and Climate Risk, among several other climate-related courses.
“Columbia Business School is now the leading academic institution in the world on the topic of climate change and business,” Usher said at the annual Tamer Institute Awards Breakfast on Earth Day.
Beyond CBS, Tamer’s Open Climate Curriculum initiative aims to accelerate the teaching of climate change globally. Introduced by Usher in 2023, the initiative brings together faculty from universities around the world to share and create teaching materials, leveraging artificial intelligence.
Beyond academics, the Tamer Institute focuses on thought leadership in climate change. One example is the annual Climate Business and Investment Conference, held on May 2 this year.
To meet the needs of current business leaders, the Tamer Institute supported the launch of the Climate Knowledge Initiative, under which students contribute to research on promising startups. Their work is highlighted for future investors and sometimes turned into case studies for CaseWorks, which develops teaching materials for CBS classrooms.
Students who take advantage of CBS’s many climate-related offerings often go on to celebrated careers in fields such as investing, finance, and policy. One example is Ron Gonen ’04, founder and CEO of Closed Loop Partners, a New York-based investment firm and innovation center focused on building the circular economy.
"Through scholarship and through our ability to bring and convene people—this is how the Tamer Institute actually moves the needle. It is truly a gem. It is unique in how impactful and successful it is, it is unique within our School, and it is unique within the University and within the Academy."
- Dean Costis Maglaras
CBS alumni are also making their mark in climate-related policy. Rohit Aggarwala ’00, who is chief climate officer and commissioner of New York City’s Department of Environmental Protection, oversees initiatives like Local Law 97, which sets strict carbon emissions limits for large buildings.
He spoke at the conference about overlooked opportunities to achieve climate resilience at scale—for example, working with small property owners who often get advice from plumbers unfamiliar with flood mitigation.
Aggarwala believes it will take time to educate providers on how to do such jobs properly, just as it took decades for the energy-efficiency sector to evolve after the 1970s energy crisis: “We’re going to need that same transition for resilience.”
He also emphasized the need to ensure that properties such as lower-income coops can comply with relevant laws. “It’s often the most vulnerable communities, with the fewest resources, that now face the highest costs to comply with the law,” Aggarwala said.
With CBS more committed than ever to climate innovation, and with the Tamer Institute supporting it, CBS alumni will continue to play a leading role in shaping the business world’s climate solutions for decades to come. Its distinctive approach to climate innovation and deep commitment to impact is preparing a new generation of leaders to drive solutions at scale.
As Dean Maglaras put it, “Through scholarship and through our ability to bring and convene people—this is how the Tamer Institute actually moves the needle. It is truly a gem. It is unique in how impactful and successful it is; it is unique within our School, and it is unique within the University and within the Academy.”
