This is the tenth in a series of stories about Clean Energy Champions—real people who are taking action to support or join the transition to a clean energy economy. Their stories illustrate the many ways you, too, can become a Clean Energy Champion.

You might develop an appreciation for the environment if you grow up on a palm tree farm, but if you’re a teenager trimming and feeding those trees, you might rather be hanging out with friends. This was the case for Chris Castro, chief of staff for the U.S. Department of Energy (DOE)’s Office of State and Community Energy Programs—which provides funding and technical support to states, tribal nations, cities and counties, school districts, nonprofits, and other stakeholders—but he also credits his upbringing with starting his clean energy career path.

Literally and figuratively, the seeds were planted when Castro was in high school: A U.S. Department of Agriculture college scholarship program gave seeds to children of farm owners to grow and sell trees. Castro planted and nurtured 5,000. At the University of Central Florida (UCF), he majored in science and environmental policy and minored in engineering, because he had seen the reality of climate change and was motivated to help solve it.

Castro became “infatuated” with microalgae as a tool to mitigate industrial emissions. He learned that the 1978 DOE Aquatic Species Program, which researched turning plant life into fuel, narrowed down 300,000 algae strains to 300 that could be used for fuel. Castro investigated which of the 300 were native to Florida. He also investigated opportunities that could help his career after college.

In his junior year, Castro landed a summer fellowship at the Office of Energy Efficiency and Renewable Energy (EERE). He remembers marveling at the multimillion dollar budgets for EERE’s technologies offices and the clean energy potential those budgets represented. He attended House and Senate chamber hearings on clean energy and called the experience “the game-changer for my whole career.”

That fall at UCF, he ran a competition to reduce energy use in the dorms, which resulted in a $50,000 cost savings in just three months. DOE profiled the case study and invited Castro to return for a second fellowship and create the next version of its student ambassador program to get students engaged with clean energy.

After graduation, Castro started a consulting firm to retrofit buildings with clean energy solutions. Nearly three years later, he got a call from the mayor of Orlando, Florida: The city had received a clean energy grant and needed an advisor to guide its use. Castro spent eight years working for the city, most recently as the director of sustainability and resilience and co-chair of the Smart Cities initiative, and saw the amount of renewable energy powering city operations jump from zero to over 20%, with 52 city facilities subscribing to solar farms. He also worked with the utilities commission to commit to a 100% clean energy transition and achieve net-zero emissions citywide by 2050.

Castro says reducing the city’s emissions is centered on increasing energy efficiency in buildings, increasing solar energy use, and electrifying transportation. His emission-reduction strategy is rooted in a holistic approach.

“It’s about living the talk. In order for us to take bold climate action, we have to look at it like peeling an onion: at home, within our neighborhood, within our city, then start to scale out,” Castro says. At home, he replaced his windows and installed low-flow fixtures and faucets, a high seasonal energy efficiency ratio HVAC system, a programmable smart thermostat, and a heat-pump water heater. He also joined a solar cooperative, which fully offset his electricity consumption and enabled him to power his electric car each day.

Castro made these investments gradually, over years. “I try to show people you don’t have to have a lot of money to reduce your carbon footprint, you just have to do it in a smart way. Start with efficiency, lower your bills, then look at renewables, then you start to migrate.”

Learn more about clean energy internships, fellowships, and jobs with EERE.