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Carbon Critical: Hydropower, the Old Renewable


Critics enjoy pointing out the drawbacks of wind and solar power. Yet the history of hydropower shows that renewables have always had flaws.

© REUTERS/Ilya Naymushin

On April 21, the US filmmaker Michael Moore released his latest documentary, Planet of the Humans, on YouTube. The film accuses environmental activists of corruption and contends that renewable energy technologies are often worse for the planet than fossil fuels: producing solar panels, it points out, requires consuming energy and mining metals.

A month later, in Moore’s home state of Michigan, two hydroelectric dams burst after heavy rains, forcing thousands of residents to flee their homes and destroying properties across the nearby city of Midland. It was lucky that no one was killed.

The Michigan dam disaster offers a chance to test Moore’s hypothesis about the dark side of renewable energy. Whereas solar power is a relatively new part of the electricity mix, humans have been using water, a renewable resource, to generate electricity at scale for over a century. Looking at the history of hydropower reveals that renewable technologies have always had flaws—and that’s just fine.

Not so Modern

The first commercial hydroelectric power plant began operating in Wisconsin in 1882, the same year that Thomas Edison opened the world’s first central coal-fired power plant. Small-scale hydropower spread quickly around the world, and by the 1930s engineers were building massive hydroelectric projects like the Hoover Dam on the Colorado River. The “white coal” cascading down the Alps provided almost all of Italy’s electricity at the outbreak of World War II.

In the post-war decades, people added hydropower almost everywhere financial and natural resources allowed it. The Soviet Union began construction of the giant Sayano-Shushenskaya Dam in 1963; it remains the biggest power plant in Russia today. In the 1970s Brazil and Paraguay built the even larger Itaipu Dam, now the second-largest power plant in the world, behind China’s gargantuan Three Gorges Dam. European countries kept expanding hydropower too, and today Norway, Switzerland, and Austria generate more than half of their electricity in this way. By 1975 humans were generating over 20 percent of their electricity from this renewable resource.

Hitting a Water Wall

However, hydropower faced mounting problems in subsequent years, even as people woke up to the dangers of oil spills and coal-related air pollution. One issue was that the dam-building spree of the long boom years meant “most of the good sites in rich countries had been taken” by 1980, as environmental historian J.R. McNeill has written.

Just as relevant was the realization that building hydroelectric dams could have some nasty social and environmental side effects.

Living near dams can be deadly. In 1975 a typhoon in China’s Henan province caused the Banqiao Dam to collapse, inundating a highly populated area. Tens of thousands drowned, and over 100,000 people died during ensuing epidemics and famines. Chernobyl may be more infamous, but Banqiao was vastly more lethal. (Like the Michigan dams, Banqiao provided not only hydropower but also vital flood control and irrigation; of the 57,000 large dams in the world, around 6,000 exist solely to produce electricity and another 4,000 both produce electricity and perform other services.)

Dams can do major environmental damage even when they don’t break, preventing fish migration and altering the ecology of the surrounding area. Take the well-known Aswan High Dam in Egypt, whose ecological impacts will endure longer than the memory of Gamal Abdel Nasser playing the US and USSR off each other in his quest for funding. Its turbines produced around a third of Egypt’s electricity in the 1980s, and it protected Egyptians and their cotton crops from heavy Nile floods. Unfortunately, the dam also prevented fertile silt from flowing from Ethiopia to Egypt, and Egypt had to use much of that new electricity to produce chemical fertilizers. Without the Nile floods, the Egyptian soil accumulated more salt, and without the Nile water that had once reached the Mediterranean, shrimp and sardines in that sea were deprived of nutrients and died.

Dam-building can have other direct impacts on humans. When serving as his country’s prime minister, Jawaharlal Nehru dubbed hydroelectric dams the “temples of modern India,” though they also displaced tens of millions of his compatriots in the 20th century. In tropical areas, creating reservoirs can lead to increases in waterborne diseases such as malaria.

The backlash against such impacts began to slow the growth of hydropower in the 1980s. People had seen too many of the negative impacts, seen too many post-colonial governments empty state coffers and risk angering their affected neighbors for the chance to cut the ribbon on a massive infrastructure project. In the early 1990s local critics, backed by Western NGOs, forced the World Bank to withdraw its support for a dam-building project on the Narmada River in India, and World Bank financing for hydroelectricity dried up around the turn of the century.

Between a River and a Hard Place

Today hydropower exists in a sort of purgatory between the polluting energy sources of the past and the safer renewable sources of the future. Its uncertain position is reflected in the language used by energy experts to describe it. For the International Energy Agency, it is one of the “modern renewables” along with wind and solar. The World Bank offers data from “renewable sources excluding hydropower,” while BP actually lumps hydropower in with nuclear energy, another low-carbon energy source that was providing almost a fifth of global electricity when the Chernobyl nuclear reactor exploded in 1986 and has become slightly less important in relevant terms since.

In any case, hydropower is still the most important source of low-carbon electricity: hydropower generated 16 percent of global electricity in 2018, more than nuclear (10 percent) and other renewables (9 percent). With demand for low-carbon electricity increasing, the World Bank has stepped up its financing of hydropower since 2008, and private companies and regional development banks facing less scrutiny have backed new dam construction in developing countries. China has stepped in as a funder in recent years in the framework of its Belt and Road Initiative, providing loans for big hydroelectric projects with few strings attached.

Yet concerns about new construction remain, which is why the European hydropower industry is focused on renovating old hydropower plants, adding turbines to existing dams, or backing smaller “run-of-river” projects that do not involve the construction of large dams. It also sees promise in “pumped storage” hydropower, which uses excess wind or solar power to pump water upwards and store energy for later.

Only a few countries are ploughing ahead with landscape-altering mega projects, costs be damned. China is building two huge dams on the Jinsha River, raising tensions with downstream neighbors who fear for their farmland. Meanwhile, Ethiopia’s construction of the Grand Ethiopian Renaissance Dam (GERD) on its part of the Blue Nile has brought it and Egypt to the brink of a “water war.” Rather than finance this contentious dam, the World Bank is now mediating between Egypt and Ethiopia.

Those three controversial projects will be a responsible for a quarter of hydropower’s modest projected growth over the next five years—IEA analysts expect hydropower generation to increase by 2.5 percent per year in the 2020s, compared with 16 percent per year for solar.

Renewable If Not Necessarily Sustainable

Hydropower, then, is an old source of renewable energy that can do major environmental damage. It is also a crucial component of the current low-carbon energy mix at a time when carbon dioxide emissions are a serious threat: China would have had to build about 20 coal-fired power stations to generate as much electricity as the Three Gorges Dam. Dams can be a useful climate change adaptation tool as well, irrigating fields to help farmers keep farming in the face of climate change-related rainfall variability and drought. Responsible policymakers know that they have to balance climate and environmental concerns, reducing the impact of hydroelectric dams and generating low-carbon electricity in other ways where possible.

And yet renewable skeptics like filmmaker Moore present the drawbacks of wind, solar, and hydropower as if they are some new issue whose discovery undermines the rationale behind the energy transition. This is uninformed nihilism. As climate policy expert Leah Stokes put it in her review of Planet of the Humans, “Renewables have downsides. As do biomass, nuclear, hydropower, batteries, and transmission. There is no perfect solution to our energy challenges.”

In short, Moore’s film misunderstands both the past and present of renewables. Renewable energy was creating problems for humans well before anyone worried about greenhouse gases: muscle power is renewable, though the horses that powered 19th-century urban transport also coated city streets in a layer of manure and forced farmers to dedicate vast tracts of farmland to growing oats. What’s more, every energy transition is necessarily powered by existing sources: early coal miners used horses; the bulldozers that built the first nuclear power plants ran on oil.

On the flip side, utilizing fossil fuels instead of renewable resources has had incidental benefits for the environment in some cases. The advent of kerosene lighting, for example, reduced the incentive to kill whales for their oil, while the switch from wood to coal spared countless acres of forests. And if the billions of people in poor countries who burn renewable wood, charcoal, or dung in open fires had gas- or electric-powered cookstoves instead, they would live longer, healthier lives.

No, renewables are not perfect. Solar panels rely on energy-intensive mining, and wind turbines can kill birds. Yet they are the best option we have. Renewable critics lean too hard on the adage that “there’s no such thing as a free lunch,” when the proverb they need to reach for is “take the lesser of two evils.”