On a clear July morning three years ago, dozens of environmental activists pushed their kayaks into the Willamette River in Portland while others rappelled 400 feet from the top of St. Johns Bridge in an attempt to block a Shell Oil ship and its drilling equipment from leaving the port and entering Alaskan waters.

A key piece of Shell’s arctic drilling fleet, the vessel had arrived in Portland for repairs but its departure was delayed by protesters chanting “coal, oil, gas, none shall pass!” during two days of civil disobedience that became known as Summer Heat.

By the time the vessel finally sailed, the stage had been set for what would be a yearlong battle, culminating in an ordinance that banned construction and expansion of fossil fuel infrastructure in the city.

Last month, the Oregon Court of Appeals upheld Portland’s ban as constitutional, affirming the city’s power to regulate the safety and welfare of its residents and sending a powerful signal to cities that they too can take the lead to limit fossil fuel use.

And while the court ruling could set precedent for similar climate action elsewhere, how Portland passed the nation’s first fossil fuel infrastructure ban holds important lessons for how other communities can use grassroots activism to implement the renewable energy transition in their cities.

“The Oregon Court of Appeals decision basically says that ‘yes, local communities do have the right to restrict against fossil fuels and the risk that they bare,'” says Mia Reback, who helped organize Summer Heat and is development coordinator at the Portland chapter of a global climate action group, 350PDX.

In the fourteen months since the Portland ban was imposed, elected officials across three US states — Idaho, California, and Washington — have publicly committed to creating similar climate action in their communities.

In part because of the roadmap Portland’s provided, city- and state-level actions opposing the fossil fuel industry are gaining momentum across the country. But it took Portland a while to find its own way.