4. Water power

Roll on, Columbia, roll on,
Roll on, Columbia, roll on,
Your power is turning our darkness to dawn.
So roll on, Columbia, roll on.

—Woody Guthrie

Figure 4.1 Edwards Dam on the Kennebec River, at Augusta, ME, just before it was breached. (© AP Images)¹

Key facts

• Water power provides about 10% of the electricity in the United States, at least half of the electricity used in about one-third of the countries of the world, and more than 90% of the electricity in 24 countries, including Brazil and Norway. Large dams generate 19% of the world’s electricity.

• The U.S. has about 80,000 dams more than 6-feet tall, many built to provide electricity.² Worldwide, about 800,000 dams exist, and about 45,000 are “large,” meaning more than 15 meters (about 45 feet) high.³

• The United States has 2,400 dams that generate electricity.

About 17% of the rivers in the United States have dams, which in total block about 600,000 river miles.

• China has the greatest number of large dams, 22,000 of them.

• In developed nations, most or all the best sites for hydroelectric power have already been tapped, and there is little potential to increase this source of energy.

• Most of the remaining undeveloped water-power sites are in developing nations.

A story about water power: the breaching of Edwards Dam

In August 1999, I traveled to Augusta, Maine, to watch the breaching of Edwards Dam. I wrote this article about it, which appeared in the Los Angeles Times on August 22 of that year. It still seems to sum up my experiences, so here is what I wrote that day.⁴

As a crowd gathered along the east bluff of Edwards Dam, a great blue heron flew low above the Kennebec River and was soon out of view, traveling downstream from where water still flowed smoothly over the 161-year-old structure. The heron had been disturbed from its usual stalking territory, perhaps by the big diesel shovel digging bucketfuls of soil from a temporary dam across the river, or perhaps by the large crowd on the opposite shore, or the noise of a helicopter and a float plane circling overhead carrying television crews.

They had all shown up today to witness the breaching of a major hydropower dam, an unprecedented event in U.S. history. The dam was being removed to save migrating fish, restore Kennebec’s ecological habitats, and improve recreational fishing and boating. If the river’s fish population increased, it might be a boon for the heron as well.

Built in 1837, the dam was operating when Henry David Thoreau canoed Maine’s rivers in the 1840s. The dam’s demise was “a bittersweet event,” Augusta’s mayor said. It was a willing and willful removal of one of the triumphs of the machine age, a piece of Yankee ingenuity that had provided power, jobs, and prosperity for Augusta, but did so no more.

Each century and each generation has had its own approach to water power and rivers. Dams were built throughout the United States to provide power for many kinds of industries, from textile mills to aluminum refineries; to store water for irrigation; to control water levels as an aid to ships transporting grain and other goods; for flood control; and for recreation. But dams greatly altered stream habitat. As Thoreau observed on the Merrimack, migrating fish such as shad and salmon, once common there, were rare in his time since they could not pass over the dams already in place by the 1840s.

When a big bell in an Augusta church announced the time to breach Edwards Dam, the shovel dug deeper and deeper into the earthen dam until a shout went up from the crowd and water began to spill through. The thin trickle, moving ever faster, turned into a frothy, mud-laden torrent running down the far side of the Kennebec, tumbling against an old mill building and turning the main channel brown as the river began to cleanse itself of 150 years of deposits behind the old dam.

Some would say that removal of the dam was righting an old wrong. Others would say it was a mistake, wronging an old right. But it was not a matter of absolute right or wrong, it was a matter of a change in our society’s needs and desires, a continuation of change and progress, of new ideas, that have characterized U.S. society.

Edwards Dam was among the first of many to be removed. It was a relatively easy decision since the dam was old and dangerous and had ceased to be of much economic use to Augusta. Maine had begun to prosper more from tourism than from the dam and its mills. The industries along Augusta’s riverbanks were closed or were using electricity generated far away, mostly from fossil fuels whose “brown” pollution didn’t seem to touch Maine’s scenic landscapes and rivers. The new environmentalism would save the city and its landowners a bundle, paying to get rid of something that might cost them plenty if it broke on its own and flooded buildings downstream. Yes, the dam seemed only a negative, threatening migrating fish such as shad, which were in trouble along the coast. The majority of people wanted the river back as a renewable resource for living things. Other sources for energy could be found.

Elsewhere, other dams have caused much more conflict, with both sides claiming the environmental high ground. Opponents of hydropower side with those who argued for the removal of Edwards Dam. Supporters argue that dams are an important way to limit greenhouse gas emissions, that the reservoirs favor many kinds of wildlife and are major sources of recreation.

So today, water power seems to be a Dr. Jekyll and Mr. Hyde. It’s a Dr. Jekyll for global warming since it emits no greenhouse gases. It’s a Mr. Hyde about river habitats and the biological diversity of life in rivers, and the living things that depend on life in the rivers, including many people. What’s the right balance about water power? Can it be an important source of energy in the future?

How much of our energy supply comes from water power today?

At present, the total U.S. hydroelectric power capacity, including pumped storage facilities, is about 95,000 megawatts, producing 2.14 million megawatt-hours⁵—about 10% of all the electricity and 3% of the total energy used in the United States.⁶ The world’s total electrical production from hydropower is about 2.3 trillion kilowatt-hours of electricity each year—about 19%⁷ to 24%⁸ of the world’s electricity. In some nations, such as Canada and Norway, most of the electricity is produced by water power.

To generate all of its hydroelectric power (Figure 4.2), the United States uses 2,400 dams. (The rest of the nation’s 80,000 dams don’t generate electricity.)⁹ About 17% of U.S. rivers have dams, estimated to block about 600,000 river miles. In the U.S. West, where water tends to be more limited than in the East, dams block almost every major river.¹⁰

Figure 4.2 Percentage of the world’s dams in major nations. (Source: World Bank)

The energy that dams provide, and how they do it

Water power is one of civilization’s oldest sources of energy, familiar to us in paintings and photographs of water mills and their water wheels of medieval Europe and earlier. These used mechanical linkages—belts, gears, pulleys—to transfer the energy in the water to do useful work. But with the modern industrial age and the invention of the electric motor and electric generator, energy in flowing water generated electricity with much greater efficiency and flexibility. Soon hydroelectric power was doing all sorts of things, from providing electricity for the milkmaid to converting bauxite ore into aluminum (as Woody Guthrie put it in one of the songs he wrote for the Bonneville Power Administration).

The first big industrial-age improvement was the invention of a turbine wheel, a rotating fin-bladed device inside a metal housing, through which a large part, or all, of a stream’s water could flow. These replaced the picturesque but less efficient water wheels that could make use of only a small part of a stream or river’s energy. The first turbine wheels were linked mechanically to machines, just like their predecessors. The next big improvement was the invention of hydroelectric generators—huge, efficient machines spun by water flowing within them, just as air moves within modern jet engines, and generating electricity directly.

Then in response to the Great Depression and the Dust Bowl of the Midwest, Franklin D. Roosevelt’s administration began construction of many major dams and created two entities for building them and operating them: the Tennessee Valley Authority (TVA), in 1933, which built 48 dams in the Southeast, and the Bonneville Power Administration (BPA), in 1937, which runs 12 major and 19 smaller dams on the Columbia and Snake rivers.

Later, the Army Corps of Engineers built six major dams on the Missouri River (mostly for flood control, irrigation, and recreation, but also for some electrical production), and the federal government also built some of our nation’s largest and most impressive dams on the Colorado River: Glen Canyon Dam, with its huge reservoir, Lake Powell, just upstream from the Grand Canyon; and Hoover Dam and its Lake Mead reservoir, downstream from the Grand Canyon. This dam made it possible for Las Vegas to become a huge urban area.

Until the 1980s, dams seemed an unmixed blessing—water power was considered good for both society and the environment. In the days of the Depression, the Dust Bowl, and the construction of the first of these great dams, Woody Guthrie, a great American folksinger and songwriter, was hired by the Bonneville Power Administration to write songs promoting the dams. He wrote more than 20 songs, some still famous, all rejoicing in the social benefits of the dams. He wrote that “king salmon” and the great Douglas fir trees would have to give way to the dams and their reservoirs, but this was okay, he said, since it was more important to provide electricity “for the milkmaid.” At a time when so many Americans were impoverished, building great hydroelectric dams seemed only a social good for all the people.

Downsides of major power dams, especially building new ones

I don’t think I should have voted for the Glen Canyon Dam. Even though it’s created the biggest tourist attraction in my state, I preferred the free-running river. I remember the river.

—Former U.S. Senator Barry Goldwater¹¹

Nowadays, building big dams is controversial and time-consuming. A case in point is a large dam to be built on the Nam Theun River, a tributary of the Mekong River in Laos. The dam, named Nam Theun 2 (NT2), was proposed in the 1980s and became a major goal for the Laotian government in the early 1990s,¹² but work on it didn’t begin until much later. By 2006, water diversion to build the dam had been completed, and people who lived on land that would be flooded were moved to new villages. Construction was finished in 2009 and on July 3, 2009, the hydro-generators sent out their first electricity, 60 megawatts.

NT2 is said to have cost $1.45 billion and at full operating capacity will produce 1,070 megawatts, 995 of which will be sold to Thailand, leaving 75 MW for use within Laos.¹³ It is the largest single foreign investment ever made in that country, and support for it comes from the World Bank, the Asian Development Bank, the European Investment Bank, and the Nordic Investment Bank.¹⁴ The World Bank estimates that the electricity sold to Thailand will give the Laotian government $30 million a year. The payback from Thailand should therefore take 50 years to equal the cost of building the dam,^{15, 16} although there is hope that the revenue will increase substantially. The World Bank supports the dam since it fits the bank’s goals of alleviating poverty and promoting economic development.

However, in 1997, in response to growing concerns about the ecological effects of major power dams, the World Bank and the Laotian government set up a panel of scientific experts to study the region’s bio-diversity, determine what the environmental and social effects would be, and recommend how best to deal with them. The three members of the panel were David McDowell, former director of the International Union for the Conservation of Nature and past New Zealand Ambassador to the United Nations; Ted Scudder, an anthropologist from Caltech and author of The Future of Large Dams;¹⁷ and Lee Talbot, one of America’s leading environmentalists and conservation scientists and primary author of the U.S. Endangered Species Act. This is clearly one of the most qualified panels that environmentalists and social scientists could hope for.¹⁸ The idea was that this panel could lead a revolutionary effort to help create a dam that is benign and helpful to people and the environment.

Even with this distinguished panel, the project met with considerable criticism. The organization International Rivers states that the project did not fulfilled its promise to deal adequately with, first, “resettlement of 6,200 indigenous peoples on the Nakai Plateau; second, the program to mitigate NT2’s impact on tens of thousands of downstream villagers; and third, compensation for villagers who have lost land and resources as a result of project construction.”¹⁹

One of the displaced villagers said, “Before we depended on the land, now we depend on the company supporting us. We used to live next to the river and could get up in the morning and catch fish for breakfast.”²⁰ It is estimated that the dam will directly affect 2% of Laotians.

A poor nation with fewer than 6 million people, Laos sees the dam as an important step forward. Although it will reduce logging in the nation’s tropical rain forests, which has been a major economic activity, it will provide a variety of new jobs linked to the power that it will generate.

Three Gorges Dam

No discussion of the modern development of water power would be complete without considering the Three Gorges Dam, the largest in the world and the most famous built in recent years. The building of Three Gorges Dam on the Yangtze River in China created a worldwide controversy that fuels the debate about hydroelectric dams.

On the upside, Three Gorges Dam offers huge power output and no greenhouse gases. Three Gorges can produce about 18,000 megawatts of electricity, the same as 18 large coal-burning power plants. (In contrast, the largest hydroelectric dam in the United States, the Grand Coulee on the Columbia River, produces 6,180 megawatts, one-third of Three Gorges’ output.) China’s largest fossil-fuel resource is coal, and pollution from mining and burning coal is a serious problem in that country. Indeed, China and the United States are seen as the primary contributors to greenhouse-gas emissions. So the really big advantage of Three Gorges is that although it generates as much electricity as 18 coal-fired power plants, it does not produce greenhouse gases.

BUT—it has resulted in widespread flooding. This huge dam, about a mile long and about 600 feet high, created a vast reservoir 370 miles long, longer than the distance from Los Angeles to San Francisco, or from Boston to Philadelphia. It flooded many small farms and rural villages, directly displaced about 2 million people, and changed scenery that had been considered among the most famous and beautiful in the world.

Pollution and sediment are also big problems. Raw sewage and industrial pollutants flow into the Yangtze River and then into the reservoir. This river also has a naturally high sediment load, increased by human activities upstream and likely to increase further with China’s rapid industrialization. As with all dams, river sediments fill in the reservoir, shortening the lifetime of the dam. Among other negative effects, these sediments will damage deepwater shipping harbors on the reservoir.²¹

Three Gorges Dam also lies within an area of active earthquakes, with their accompanying large landslides, raising international concern that a major quake could damage the dam, flooding the city of Wushan downstream, killing many of its several million people, and heavily damaging human development and the landscape downriver.

Some opponents of the dam—not opposed to water power in general but to Three Gorges specifically—point out that a series of smaller dams on the Yangtze River tributaries could have generated as much electric power with less environmental, scenic, and social damage, and without such serious danger from earthquakes.

Dams, in sum

What is the best answer to the question of whether dams should be an important source of energy in the future? Every new dam will cause some damage to wildlife habitat and biodiversity, in settled areas force the migration of many people, and in most cases cause the loss of some of the world’s greatest scenery. The choice is between these undesirable effects and a dam’s contribution to reducing greenhouse gas emissions and therefore the potential effects of global warming.

Perhaps the best summary of the role of large dams in our energy future was written by Thayer Scudder, author of The Future of Large Dams:

Adverse environmental and social impacts of large dams are contributing to serious degradation of global life-support systems. Environmental impacts are degrading river basin ecosystems that, in many countries, are national heartlands. Social impacts are further impoverishing tens of millions of river basin residents who, to survive, cause further degradation of surrounding natural resources. Furthermore, the development potential of large dams is seldom realized since of the complexity involved, since of institutional inadequacies, since of implementation uncertainties and since of corruption.

...Yet large dams remain a necessary development option for providing water and energy resources to populations in late-developing countries that are in crisis since they have expanded beyond the carrying capacity of their environment. Even then, a decision to build a large dam should only be based on an open and transparent options assessment process in which relevant stakeholders are fully informed of the risks involved. If a decision is made to proceed, state-of-the-art guidelines should be followed in order to reduce known disadvantages, some irreversible, to the extent possible and to increase an equitable distribution of advantages.²²

Harnessing the power of rivers without dams

An alternative to damming a river is to use hydrokinetic devices—machines that float either on or below the surface of the river and generate electricity from the energy in the river’s current. A surprising example is a plan to put a submerged floating turbine generator in New York City’s East River. The turbine has been developed, but its installation has been delayed by concerns about effects on the river’s fish. Verdant Power, the company that developed this turbine, says that the river’s currents and width would allow enough of these turbines to generate as much as 10 megawatts of electricity in the East River without disrupting ship and boat traffic. The experimental machines are slated to power a Gristedes grocery store on Roosevelt Island.²³

Can water power help solve the problem?

Could water power’s contribution to our energy supply be increased greatly in the future? No, or at least highly unlikely. But if so, is it a good way to go? The answer is yes and no. As for conventional approaches to water power—large dams with electrical generating stations fixed in place—most good sites are already in use in North America and Western Europe. Good sites still undeveloped for water power exist elsewhere but are environmentally and societally controversial. Like the new dam in Laos and Three Gorges Dam in China, many remaining conventional water power sites are in developing nations and newly emerging industrializing nations. In both situations, new dams will affect biological diversity and displace many people, forcing them to seek new places to live and often new kinds of work. Other locations with still-abundant water power are wildernesses and remote places like eastern Siberia, where biological diversity will be affected. There is strong environmentalist opposition to any new dams.

Thinking more broadly, is there any way that even a combination of conventional and novel technologies could allow water power to significantly increase America’s energy supply? The Electric Power Research Institute, a nonprofit corporation funded by the major electric power companies, estimates that enough locations are available, both tapped and untapped, to increase U.S. hydropower capacity 24% to 27%.²⁴ This would include increasing the generating capacity at existing hydroelectric dams; adding generators to dams that don’t have them, building some small, low-power dams; using the new hydrokinetic technology to generate electricity from flowing water without building a dam; and also using ocean waves (see Chapter 8, “Ocean Power,” on ocean energy). Excluding ocean energy would lower the projected energy increase to 14% to 15% and boost water power’s contribution to total U.S. energy use from 3% today to about 4%.

Worldwide, the picture is brighter in terms of potential energy production (and ignoring, for the moment, social and environmental effects). At present, total world use of hydropower is 2,900 billion kilowatt-hours, about 2% of the total energy used by all the people of the world.^{25, 26} According to the International Hydropower Association, an organization that promotes water power, hydropower could increase to about five times the present level, providing as much as 8% of today’s worldwide energy use. However, not all this potential growth appears economically feasible. About one-third (36%) of the world’s economically feasible water power sites have been developed. “Most of the remaining hydropower potential is in Africa, Asia, and Latin America:”²⁷ The International Hydropower Association observes that “two billion people in developing countries have no reliable electricity supply, and especially in these countries for the foreseeable future, hydropower offers a renewable energy source on a realistic scale.”²⁸ Proponents argue that water power “continues to stand as one of the most viable sources of new generation into the future.”²⁹

In sum, we conclude that hydropower can provide only a minor overall contribution to the world’s energy use, but locally and regionally—as in China, India, and other developing Asian nations and some parts of Africa and South America—water power is almost certainly going to increase unless other forms of alternative energy become easily available.

The bottom line

• Water power is clean, doesn’t pollute the air or soil, and doesn’t contribute to global warming.

• However, hydroelectric dams and reservoirs alter river and stream habitats and are now targeted for removal by many environmental groups concerned about loss of habitats for fish, such as salmon, and streamside wildlife and vegetation.

• More than 650 dams have been removed in the United States and more than 200 since 1999.³⁰ Removals are in part to improve habitats, but also because some dams have become unsafe.

• Most good sites for hydropower are already in use in North America and Western Europe. Good sites yet undeveloped for water power exist elsewhere, but these are environmentally and societally controversial. They offer local and regional benefits at the price of undesirable local and global effects, including the displacement of people and destruction of their way of life.