Successful technologies follow an S-shaped adoption curve. Sales move at a crawl in the early-adopter phase, then surprisingly quickly once things go mainstream. The top of the curve represents the last people to make the transition. Even in 2022, a tenth of humanity still doesn’t have electricity.
Five percent isn’t a universal tipping point. Some technologies flip sooner, others later, but the basic idea is the same: Once the tough investments in manufacturing have been made and consumer preferences start to shift, the first wave of adoption sets the conditions to go much bigger. By examining the countries that reach each tipping point first, we begin to get a sense of what to expect from those that follow.
Intermittent renewables tend to work better in combination—so when the sun sets in Spain, wind from Denmark might make up some of the gap. But even on their own, specific types of renewable energy show distinct adoption curves. Deploying enormous wind turbines can be difficult, so adoption is more gradual. Solar cells, on the other hand, can pop up just about anywhere once they’re affordable, so growth after the tipping point can be more explosive.
One phenomenon underpinning the tipping points is known as the experience curve. Wind and solar are technologies, not fuels, so the more panels and turbines are deployed, the better we get at making them. Every time the global supply of solar doubles, the cost of adding more installations declines by almost 30%, according to decades of data from BloombergNEF.
As more countries tipped into mass adoption, wind and solar became the cheapest sources of new electricity capacity worldwide, according to BloombergNEF data. Cost declined so much that it's no longer the biggest obstacle to expansion. “Now it’s about permitting, interconnecting, central planning around grids,” says Logan Goldie-Scot, head of clean power research at BloombergNEF. “These processes aren’t always able to keep up with the economics.”