Let the sun in

This Sunday marks the first “Sun Day”: a day of activist mobilization in the United States to celebrate “the power of renewable energy,” and solar energy in particular. The name of this event—“Sun Day”—might suggest that photovoltaics is a thing for nostalgic hippies singing “Let the Sunshine In,” marginal and without a future. Quite the opposite.

To understand this, we just have to “follow the money,” as António Guterres, the UN Secretary-General, noted in July . Last year, $2 trillion was invested globally in “clean” energy. That’s $800 billion more than investment in fossil fuels, and represents an increase of nearly 70% in ten years. According to forecasts by the International Energy Agency , the combined contribution of photovoltaics and wind to the global energy mix is ​​expected to increase from 15% in 2024 to 17% in 2025, reaching nearly 20% in 2026 – “nearly five times more than just a decade ago, when these energy sources accounted for only 4% of global production.” They are also expected to cover more than 90% of the increase in global electricity demand this year.

China is particularly fond of solar panels. In the first six months of this year, it installed 212 gigawatts of power—enough to simultaneously power more than 2 billion 100-watt light bulbs. That's twice as many as in the first half of 2024, which was already a record. And in May alone, 100 solar panels were installed in the country every second . “No other energy source has ever seen such rapid growth , ” insists American journalist and activist Bill McKibben, the spearhead of Sun Day and whose recent book, Here Comes the Sun, highlights the underestimated potential of solar energy to decarbonize our energy supplies, in Rolling Stone.

The fight against climate change, however, is not the only driver of growth in renewable energy. Certainly not in the United States, where the president halted wind power projects and, in August, ended subsidies allowing hundreds of thousands of homes to install solar panels on their roofs.

Many professionals gathered in Las Vegas from September 8 to 11 for RE+ , the largest annual gathering of the American solar and energy storage industry, were optimistic, as Canary Media observed . They see AI and its energy-hungry data centers as an unexpected boon. Not only can these manufacturers offer cheap electricity—in 2024, solar photovoltaic was, on average, 41% cheaper than the least expensive fossil-fuel alternatives —but they can also respond quickly to demand. “Because it is immensely easier to assemble mass-produced solar panel parts directly on site than to build a traditional power plant,” Canary Media notes.

Not that we should be satisfied with an ever-increasing demand for electricity. But we can be pleased that the solar craze isn't driven solely by environmentalists. Perhaps they will have more influence than the participants in the first Sun Day...

The cost of extreme events

The heatwaves, droughts, and floods that hit Europe this summer “caused economic losses of at least €43 billion,” or 0.26% of the EU’s GDP, and the annual bill could “ reach €126 billion by 2029,” according to a study by the University of Mannheim (Germany) and the European Central Bank reported by The Guardian. Le Soir details: “Heat reduces productivity,” while “drought mainly affects agriculture” and “floods cause direct damage to infrastructure and buildings, as well as indirect losses, such as disruption to supply chains.” Read more here.

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