Why you should care
These countries are green, but the hydropower they need could face big challenges thanks to climate change.
Brazil’s 2015 summer was hot, very hot. With temperatures soaring over 100 degrees and the worst drought in the country’s history in full swing, the taps in São Paulo ran dry. But, perhaps less predictably, the drought also meant the lights went out. Brazil’s government — dependent on hydroelectric power generated by its dams — had to implement rolling blackouts to cope with energy demand.
It was a dire situation caused by a surprising statistic. Though renewable energy is often thought to be the province of wealthy, developed countries like Norway, Brazil generated 73.9 percent of its electricity from renewables in 2015, and in 2009 it got 88.9 percent of its power that way. And it’s not even close to being in the lead. Neither is Norway. In fact, according to the World Bank, as of 2015, the latest year for which worldwide data is available:
Four countries generated 100 percent of their electricity through renewables: Albania, Lesotho, Nepal and Paraguay.
This has surprisingly little to do with solar panels and windmills. In fact, these countries hardly even invest in what we would identify as renewable energy today. They get their energy from dams, and have been doing so for some time now. In 1990, Nepal and Paraguay got 100 percent of their electricity from renewables. By comparison, the United States got 11.5 percent of its electricity from renewables that year; in 2015, that share had only grown to 13.2 percent. In 2015, 23 percent of the world’s electricity was generated from renewables.
At the moment, hydropower is the leading renewable energy source in the world. According to the International Energy Agency, in 2016 hydropower produced 75 percent of total renewable energy, while solar panels trailed with just below 6 percent. Without counting hydropower, only 6.7 percent of the world’s energy was generated via renewables in 2015.
“It’s probably underrecognized,” says Declan Conway, a research fellow at the London School of Economics, where he studies hydropower in the developing world. “Some African countries, of course, have a low total energy production, but it’s surprising for many people that hydropower plays such a large role in energy generation for these countries.” And even though attention for it dropped after criticism of their social and ecological effects peaked during the 1990s, hydropower still seems to have a lot in store for us, says David Gernaat, a researcher at the Utrecht University in the Netherlands, where he assessed the future potential of hydropower. “In theory, if we use all possible suitable sites to build dams, we could fill two-thirds of the current world electricity demand with hydropower,” he says.
That hypothetical illustrates hydropower’s unmet potential, but also its limitations. In fact, climate change — and the predicted increase in extreme-weather-like droughts — is expected to dampen hydropower’s effectiveness significantly, as the drought did in Brazil in 2015. “If there are droughts, which in many locations will only get more frequent thanks to global warming,” explains Conway, “dams are going to fail more often if we don’t adapt them.”
Still, dams remain an attractive option for some. The developing world, in particular, has seen a hydropower renaissance in recent years. A 2015 study, for example, found that 3,700 major dams were planned or under construction at that time, with large concentrations in Brazil, the Balkans, Southeast Asia and West Africa. But that’s not true everywhere: In Europe and North America, many countries are actually decommissioning old dams. While the International Energy Agency’s World Energy Outlook predicts that hydropower will nearly double in terms of power generated between 2017 and 2040, it’s not predicted to increase as much as solar, which the agency predicts will pass hydropower in importance by 2030 and pass coal in 2040. In 2017, wind power overtook hydropower for the first time as the most important renewable energy source in the European Union.
Beyond its fragility in the face of a changing climate, hydropower isn’t a favorite of sustainability advocates. Large dams often have a myriad of negative social and environmental consequences, and historically environmental groups have opposed large-scale hydropower. “Hydropower is contentious to put it lightly,” says Conway. Recent research showed that the stagnant water in dam reservoirs still generates methane, thus contributing to global warming, although not all dams have this feature. People are often displaced to make way for reservoirs, dams flood natural habitats and river flow regimes get disrupted by large-scale hydropower.
This debate was front and center in the U.S., where Rep. Alexandria Ocasio-Cortez’s push for a Green New Deal last month called for 100 percent renewable energy within a decade. Environmental groups demanded that the deal limit the definition of renewable energy … to exclude large-scale hydropower.
“Some major environmental groups have long opposed large-scale hydropower,” says James Temple, senior editor at MIT Technology Review, where he covers renewable energy. Still, he called hydropower “essential” and one of the “most powerful tools” to drive a change toward a sustainable energy future.
One possible solution out of this deadlock could be small-scale hydropower. These smaller installations — which are often lower impact — have in some places powered communities without the negative environmental effects of large dams. That has convinced some environmental groups, like International Rivers, to let skepticism of hydropower slide. But not always: An assessment last year of small-scale hydropower in Albania, for example, found that its mini-dams didn’t respect environmental regulations or consult with local communities — exactly the same problems people have with regular-scale hydropower.