Electric bikes parading through city streets. The afternoon light glinting off clusters of floating solar panels. Neighbors guiding visitors through homes warmed by heat pumps, battery storage systems glowing on walls. 

These sound like scenes from a clean energy expo or a hopeful science fiction novel, but they’re neither. They’re just a few of the hundreds of events planned for “Sun Day,” a new national day of action on September 21 meant to celebrate the momentum of clean technology — and to confront the political and institutional barriers slowing its wider adoption.

The optimism of these world’s fair-esque celebrations of technological progress feels slightly at odds with the current politics surrounding clean energy. Under President Donald Trump, the U.S. has doubled down on fossil fuels in the name of an “energy emergency.” The administration has extended the life of polluting power plants locals don’t want and rolled back clean energy tax credits passed under former president Joe Biden. It’s not just the federal government — some states and local governments have also been passing rules making it harder to approve renewable energy projects. 

Yet despite the political headwinds, clean energy has made real progress, which Sun Day aims to put front and center. Last year, 96 percent of new power plant capacity built in the U.S. was carbon-free, coming mainly from solar, battery, and wind power. Wind and solar are the cheapest sources of electricity today, even without the federal subsidies. 

That shift has changed the game, according to Bill McKibben, an author and lifelong climate activist who is spearheading Sun Day.

“For most of the history of the climate movement, we operated in a world where fossil fuel was cheap and renewable energy was expensive,” McKibben said. “Now we live in a world where economic gravity is pointing the other way.” 

As much as Sun Day feels futuristic, it’s also all-in on nostalgia. The idea itself harkens back almost 50 years. In 1978, President Jimmy Carter proclaimed May 3 as “Sun Day,” and people across the country celebrated the dawn of the “solar age.” In Washington, D.C., the event drew 20,000 people, more than the original Earth Day in 1970. The events included watching a solar-powered hot dog cooker in action. A year later, Carter climbed onto the roof of the White House to show off 32 newly installed solar water heating panels — not the photovoltaics common today, but similar-looking devices that capture thermal energy — announcing plans for the country to get 20 percent of electricity from renewables by 2000. 

The U.S. eventually hit that benchmark — but not on the timeline Carter planned. While the government initially poured money into developing solar and wind power after gas prices skyrocketed following the OPEC oil shock of 1973, federal fervor for “alternative energy” didn’t last into the next decade.

Carter’s successor, President Ronald Reagan, slashed federal resources for developing solar and wind. During a White House remodel in 1986, his administration even tore down the solar water heating panels Carter had put up, ostensibly as part of “roof repairs” — but given his well-known support for the fossil fuel industry, people read into the symbolism. Solar power didn’t reappear at the White House again until after the turn of the century, when President George W. Bush installed photovoltaic panels and solar thermal heaters for the pool and a maintenance building, though without ceremony. In 2013, President Barack Obama installed more solar panels on the building’s roof, accompanied by his announced intention to boost U.S. solar power.

White House home improvement wars aside, solar power has long been a technology Americans generally support. As recently as 2020, 90 percent of U.S. adults were in favor of expanding solar power, according to polling from Pew Research Center. But a growing partisan divide is eroding that common ground. Republicans are now much less supportive of expanding wind and solar power than they were just five years ago, and as a result, Americans’ support for solar has slipped to 77 percent. 

“This divide in renewable energy seems not really specifically about the facts — it is more about their feelings,” said Serena Kim, a data scientist and researcher at North Carolina State University. Earlier this year, her study analyzing millions of posts on Twitter found that the share of social media posts painting solar in a negative light quadrupled between 2016 and 2022 (this was before Elon Musk took over and turned the platform into X). Kim found that support for solar was waning in Republican-leaning areas and across the South. 

Yet the politics of clean energy isn’t as simple as right versus left. “It’s all over the place,” McKibben said. “I don’t think it fits easily on an ideological spectrum.” Some environmentalists worry about big solar projects cutting across animal habitats; meanwhile, unlikely allies including ranchers, veterans, and even oil and gas interests have banded together to block or weaken bills attacking renewable development. In Texas, the state where clean energy is growing the fastest, rural Republican lawmakers worked to protect renewables from a particularly restrictive bill this year. 

Solar technology itself even has a libertarian bent. “It’s more independence, it’s local control — all the things that the right-wing libertarians want,” said Daniel Kammen, an energy scientist at Johns Hopkins University. 

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He says that some of the resistance to switching to renewables may be rooted in irrational logic, a nostalgia for fossil fuels that has lodged itself in the American imagination. “We have a mindset that this dirty energy world is cheap, available, and plays into the American way,” Kammen said.

But climate advocates point out that the price of fossil fuels has long been kept artificially low, in part due to the industry’s efforts to avoid paying for the environmental and social costs associated with their continued use. To remedy that situation, activists have adopted strategies such as taking companies to court over damages from extreme weather and advocating for a price on carbon dioxide that reflects its environmental harm. Others have turned to direct action, raising costs for fossil fuel companies by delaying or halting new pipeline projects before they have been completed.

Jamie Henn, the founder and executive director of the communications nonprofit Fossil Free Media, said that the upcoming Sun Day’s focus on advocating for clean energy is an addition to that older strategy, not a pivot. “It felt like the most important role for advocates was to hold back the expansion of fossil fuels until clean energy could catch up and be ready for prime time,” he said. “And now we’re there.” 

But even before it has taken place, Sun Day 2025 has already sparked debate — some say its optimistic outlook appears naive in the second Trump era, while others argue its embrace of ’70s nostalgia will fail to bring new people on board. The whole “Sun Day” framing was actually a little coincidental: The theme was initially “Sky Day,” McKibben said, but the graphic designers working on the logo struggled to draw an image of the sky. They kept drawing the sun instead.

The way organizers see it, Sun Day is a chance to help banish outdated perceptions about solar and wind. McKibben hopes the event will help the public to stop thinking of clean energy as a premium lifestyle choice; no longer as the Whole Foods of energy, but the Costco. 

“What we wanted to do is underline the new reality that this is no longer ‘alternative energy,’ as we’ve called it for 40 years,” he said. “It’s now the commonsense, obvious, straightforward way to power the world.”