Climate activist, academic and journalist Bill McKibben’s nonprofit 350.org convinced investors representing $40 trillion to divest from oil and gas companies over the past decade.

Now he’s using his voice and organizing platforms — 350.org and Third Act — to raise awareness about the “explosive spike” in renewable energy adoption around the world, especially electricity from the sun. 

McKibben’s latest book published in August — “Here Comes the Sun: A Last Chance for the Climate and a Fresh Chance for Civilization” — offers a hopeful account of how solar power is lifting up communities in Africa, Pakistan and China and the rural U.S.

“We live on a planet where the cheapest way to make energy is to point a sheet of glass at the sun,” McKibben told me in the latest episode of Climate Pioneers. “That changes the dynamics in many, many ways and should be changing the decision-making for corporations. It certainly is around the world.”

New renewable generation added 585 gigawatts of power worldwide in 2024, up 15.1 percent from 2023. In the U.S., 90 percent of the additions came from renewables, including 39.6 gigawatts of solar power. There’s now enough solar capacity in the U.S. — about 220 gigawatts — to satisfy 7 percent of U.S. electricity demand.

That growth continues in the face of President Donald Trump’s intensifying assault on U.S. solar and wind development through executive orders, tax rule changes and permit revocations, said the 64-year-old author of more than 20 books about climate change.

Here are four highlights from our conversation:

Solar power, the ‘Costco of energy’

The Trump administration’s policies ignore the reality that developers and utilities can add solar and wind power to the U.S. electric grid more quickly than natural gas or nuclear plants — in months compared with five years or a decade, respectively. 

Corporations with climate commitments may sign clean power contracts to make emissions claims, but it’s also cheaper, McKibben said. For example, the levelized cost of solar energy was $61 per megawatt-hour in 2024, compared with $76 per megawatt-hour for natural gas.

“I have no idea why any business would want to pay more for a primary input like energy, especially when their competitors in other parts of the world are going to be paying less and less and less,” McKibben said. “This is a strategy, at the moment, for choking the American economy. We need some businesses willing to stand up and move against it wherever they can.” 

The fossil fuel industry has broadcast the idea that alternative electricity is more expensive, when the reality is no longer true. “We think of it as the Whole Foods of energy, nice but pricey,” he said. “It’s actually the Costco of energy now: it’s cheap, it’s available in bulk, it’s on the shelf, ready to go.”

A nationwide rally to highlight that narrative, Sun Day, is scheduled for the Sept. 21 autumnal equinox. 

Texas, the biggest installer

One place the message is getting through is Texas. Despite Republican lawmakers’ attempts to slow down renewables adoption in the state, Texas installed more solar electricity in 2023 and 2024 than any other state, including California. 

Texas is also installing energy storage technology at the quickest pace in the U.S., motivated to prevent catastrophic blackouts — such as a 2021 winter storm outage that left 4.5 million customers without power, some for days. The storage capacity tripled to 8.6 gigawatts i