Editor's note: The following edited interview with Mike Sale and Chuck Coutant, both of ORNL's Environmental Sciences Division, explores the issues involved in developing hydropower resources in the United States. ORNL conducts assessments and other studies associated with licensing hydropower projects for the Federal Energy Regulatory Commission. It also performs research for the Department of Energy and others on methods to avoid or minimize the environmental impacts of hydropower projects and provides advice to other state and federal agencies and private industry. Sale is leader of the Hydrosystems Group in the division's Ecosystems Studies Section and program manager for FERC projects for the Energy Division. Coutant is a senior ecologist in the Environmental Sciences Division.

Why is hydropower important to the United States?

Mike Sale: The energy of flowing water is the most readily available, renewable, and clean domestic source of electricity that we have right now. It is available in most parts of the country that have high rainfall and mountainous areas. In terms of total production, hydropower is America's leading renewable energy resource; it is more reliable and efficient and less expensive than geothermal, biomass, wind, and solar energy. Perhaps most important, it is a clean source of power--it produces no carbon dioxide, sulfur dioxide, nitrous oxides, or any other air emissions. In addition, it produces no solid or liquid wastes.

Hydropower is also one of the least expensive sources of electricity in the United States. For every kilowatt-hour (kWh) of electricity produced by a hydropower plant, only 0.6 cents is needed to finance its operation and maintenance. By comparison, these costs at nuclear and coal plants are 2.2 cents/kWh and 2.1 cents/kWh, respectively. Our own region, the Tennessee Valley, has the benefit of low electrical rates primarily because a high percentage of its electricity comes from hydropower.

Currently, hydropower is a critical component of many electrical systems. Throughout the world it provides one-fifth of the electricity used, and it is second to fossil energy as a source of power. In the United States, it provides 10% of the electricity used, down from 14% 20 years ago, but more than petroleum and far more than the other renewable energy technologies combined. U.S. hydropower plants produce the energy equivalent of 500 million barrels of oil per year. On a regional basis, hydropower is a source of 14% of the electricity used in the Rocky Mountain states and 63% of that used along the Pacific coast. The Pacific Northwest is the region of the country that relies most heavily on hydropower; two-thirds of its electricity comes from its 58 hydroelectric dams.

I don't mean to imply that hydropower is problem-free, but these facts illustrate the importance of hydropower.

What is the status of the nation's hydropower resources?

Sale: About half of this country's hydropower projects are federal and half are nonfederal. Nonfederal hydropower projects receive 50-year licenses from the Federal Energy Regulatory Commission (FERC) and must be periodically relicensed. For example, some 156 hydropower projects built in 1943 will have to meet new requirements this year before their licenses are renewed. Further modifications may be required to protect environmental values, such as the declining salmon population in the Pacific Northwest.

In some cases, instead of renewing a license, FERC may decide the best solution is to remove the dam and restore free flow to aid salmon migration. These decisions could result in a reduction in hydropower production and an increase of as much as 8% in electricity rates for consumers in the Pacific Northwest.

Through our contracts with FERC and DOE, ORNL is involved in making recommendations on the requirements that should be incorporated into the operating licenses of hydroelectric power plants. The Laboratory supports development of hydropower that is compatible with the environment.

How will hydropower be replaced if it is lost?

Sale: The impacts of lost power production during relicensing will probably be greatest in the areas of the country that rely on hydroelectric dams for peaking power--electricity needed during times of high demand. These dams store large amounts of water and then release it quickly to match peak demands. Associated water-level fluctuations in rivers can have undesirable environmental and social effects. Given today's sensitivity to environmental values, such projects may not be allowed to continue this type of operation. Hydropower peaking may have to be replaced by gas turbines or coal-fired plants or conservation programs to encourage less use of energy.

Chuck Coutant: If part of the hydroelectric capacity is lost, the power can be supplied by other parts of the power grid. For example, the Canadians are anxious to sell hydropower to the United States. Our country's biggest foreign source of power is Quebec Hydro, which sells a tremendous amount of electricity to New England and New York City. The Pacific Northwest could import more power. Of course, doing so would aggravate our balance-of-payments problem. It should also be pointed out that the large Canadian hydropower projects have serious environmental impacts.

In addition to producing clean power, what are some other environmental benefits of hydroelectric dams?

Sale: Reservoirs at hydropower projects have a large recreational value; they are extensively used for fishing, boating, water skiing, and swimming. They offer expanded habitats for fish, ducks, geese, pelicans, eagles, and ospreys. They also provide storage for water supplies and help control floods, minimizing soil erosion. Recreational opportunities almost always increase where hydropower is developed.

What are the adverse environmental impacts of hydropower projects?

Coutant: Because most hydroelectric projects have dams, a river habitat is often replaced by a lake habitat. Thus, habitats for wildlife on land and for organisms in the water are destroyed or altered by impoundments of rivers. Examples in Tennessee are the Little Tennessee River and Tellico Lake. The biggest issue in the Northwest has been blocking upstream and downstream movement of fish. Salmon must be able to migrate upstream from the ocean to reproduce in fresh water. Even with the use of fish ladders to help salmon go up over dams and enter upstream spawning areas, the presence of hydroelectric dams essentially has changed the migration pattern of fish. The coho, chinook, and sockeye salmon populations of the Northwest, which once were abundant, are either on or will soon be on the endangered species list. They are headed for extinction, in part, because of hydropower. However, federal dams, not nonfederal dams, are primarily responsible for the reduction of the Pacific Northwest salmon population from about 16 million to 300,000 wild fish each year. The bottom line is that hydropower production is decreasing as new environmental protection is enforced.

Another big problem now is getting the young fish back downstream and into the ocean. On the way they can be killed as they pass through the turbines.

Development of hydroelectric dams can have adverse effects on water quality in several different ways. Tree clearing can result in soil erosion and landslides, causing a buildup of sediments that can clog up streams. Spilling of water over spillways can result in supersaturation of the water with gases from the air. The gas bubbles, which are absorbed into fish tissue, may cause damage and ultimately kill the fish. Supersaturation was a big problem in the Columbia River. Then it was determined that the high pressure from high water plunging down over the spillway into the basin below forced atmospheric gases into solution, making the basin water supersaturated.

Poor water quality for aquatic life can be a problem in the Tennessee Valley because our reservoirs have limited natural flow in summer. Thus, water becomes stratified, with warmer water collecting at the surface and cooler water lying at the bottom. Because the bottom water is isolated from aeration, it loses its oxygen. Because this water is very cold and low in dissolved oxygen, striped bass and other fish cannot live in it.

When this deep water is passed through hydropower turbines, it is still low in dissolved oxygen and it can make the river downstream of the dam uninhabitable, as well. Lack of oxygen in deep reservoir water can cause certain metals to dissolve more readily from surrounding rocks, and these metals are released to the downstream river where they can cause problems.

Sale: Another problem with dams is that, even if the water quality is not degraded, major habitat changes can occur if the natural hydrology of the river is changed. This issue is normally lumped under the term "instream flow" problems. If the amount of water released downstream changes, either on a seasonal basis or, in the short term--say, on an hourly basis--that can have adverse effects on fish and other organisms.

Coutant: An important advantage of hydroelectric dams for power production is that generation patterns can be easily controlled and the release pattern can be made to fit the changing levels of demand for electricity. In a typical daily generating cycle in the summer, the highest demand comes at midday and afternoon because of the need for lots of air conditioning. Like a yo-yo, the river level goes down and up as water is dumped fast in a high electricity demand period and held back during low demand periods. For a shallow river, these fluctuations are like the tide coming in and out. Flow fluctuations can strand fish in shallow water and dry out the habitat. Thus, the change-of-flow rate must be regulated to protect the environment.

Sale: The need for minimum flow to protect aquatic habitat is the most common problem that must be addressed in licensing and relicensing hydroelectric dams. If the flow is too low, fish or other organisms may suffer. Minimum flows are established to protect a wide range of natural resources, such as fish, water snakes, and, in unusual cases, even resources like the fossilized tracks of dinosaurs. Depending on the location of a project, dam releases must be satisfactory for kayakers and white-water rafters or for Native American tribes to carry out their traditional religious practices. Instream flow must be regulated to protect all these interests.

Can these environmental problems be solved?

Sale: In most situations, the answer is a strong yes. Many environmental problems of hydropower are fixable, and ORNL is making important contributions in this area. Proper siting, design, and operation can solve most of the problems. We have already mentioned the use of fish ladders, aeration, and flow control on large dams. These are examples of environmental mitigation, actions by which impacts are avoided, minimized, offset, or somehow compensated for. At hydroelectric projects, a number of actions can be taken to avoid or minimize an impact before it occurs. ORNL staff have been actively involved in evaluating these problems and designing solutions for more than a decade. Right now, we are helping DOE start up a new technology development program with industry cost-sharing to make hydropower more environmentally friendly.

Coutant: At large dams in the Pacific Northwest, fish ladders have been around for years to get adult salmon from the ocean past the dam into the river above so they can hatch their young in fresh water. The fish ladder is a classic example of mitigation. Now it is being realized that even resident fish move around a lot seasonally in fresh water for spawning and migration. Thus, they need some kind of passage. In Oregon, resident trout, which migrate for dozens of miles in the fresh water of the Klamath River, benefit from fish passages. Using fish ladders, they go from the main river environment, which essentially has no spawning habitat, into a few selected tributaries, where their spawning occurs. Their young spread out through the river and then, as adults, swim past the dams to return to the spawning area and start a new generation.

In many cases, if turbines are designed right, developers can avoid the problem in which fish are drawn into the turbine blades and killed. Intake screens can be designed to prevent fish from being drawn into the turbine. Certain turbine designs having blades that are properly spaced and turned at the right revolution are not a threat to fish. What is needed is a good standard design for turbines that is proven to protect fish and that will be considered for use by all developers of hydropower.

It is also known that turbines can be operated to minimize their harmful effect on fish. Traditionally, hydropower operators tilt the blades of a turbine rather than stopping it when they want to change the horsepower applied to the generator. Such operation causes considerable turbulence, killing most of the fish passing through. However, research has shown that running a turbine as close to maximum efficiency as possible not only generates power efficiently but also allows more of the fish to pass through unharmed. Today, on a big hydropower dam such as on the Columbia River, which has a dozen or more turbines and generators in a line, the most effective operating scheme is to keep some turbines fully on and others off to match the power demand.

What are some other examples of mitigation?

Coutant: There are many examples where actions are taken to fit the particular circumstances. For example, if a developer is going to destroy a wetland habitat by flooding the land to make a reservoir, the developer can compensate by setting up a wildlife refuge nearby. In this way, loss of habitat in one area is compensated for by creation of habitat in another. In another example, developers of a hydropower project may acknowledge that their operation may kill a certain number of fish per day in the turbines. So, to make up for this loss, they agree to build a fish hatchery capable of producing an equivalent or greater number of fish.

What other conflicts and issues arise in hydroelectric development?

Sale: In gathering information on the impacts of relicensing hydroelectric dams, we have found that these dams' multiple uses are both their biggest strength and their biggest weakness. It is a weakness because of the conflicts among many different vested interests on how to use a reservoir system. For example, the white-water rafters disagree with the reservoir bass fishermen on the amount of flow needed. Developers of residential areas along the shorelines of existing lakes are in opposition to the people who want to preserve the forest to protect its endangered species. A classic conflict over water use is the one between those who want to use the water in the dam strictly for hydropower generation and those who want to divert some of it to supply industrial and agricultural needs. Ironically, hydropower being a nonconsumptive water use is more compatible with environmental instream values than consumptive, out-of-bank uses, such as water supply.

Coutant: Interestingly, authorized uses of a hydroelectric project can have conflicts, and there can be conflicts between authorized uses and other demands. For example, authorized uses of the TVA dams are power generation, flood control, and recreation such as fishing, swimming, boating, and water skiing. Here's the problem. To achieve flood control, it is desirable to lower the dam level by releasing more water over the spillway, making space for the extra water that a flood would bring. However, dock owners who use the lake for recreation do not want the reservoir dropped 30 feet in the summer because then they could not use their docks. So TVA has developed standard rules on raising and lowering the lake level to try to accommodate both the recreation interests and the need for flood control.

Sale: Another issue is that, in the Northwest and elsewhere, the rights of Native Americans must be protected, even if it conflicts with what the rest of society wants. Since the 1800s the tribes have had a treaty with the U.S. government that recognizes them as a separate nation. They can set their own rules for fishing and environmental use. They have a right to have enough salmon at the spot where they usually fish, to have enough water in the river for their traditional religious bathing practices, and to ensure that no water touches any manmade structure that has religious significance.

In the Skagit and Nooksack river basins in Washington, we have been interviewing tribal members to determine the problems they have with present and planned hydro facilities and to explore solutions. We ask general questions about the possible impacts and the types of mitigation or compensation they would consider acceptable.

Coutant: In looking at the socioeconomic aspects of a hydroelectric dam, we have to consider its relative value as an environmental resource versus its value as a source of power. It used to be accepted that the value of hydropower was so great that only major environmental damages would offset it. Some people are questioning that assumption now. More and more, people are insisting that hydropower pay its way so that the result is no net loss for fish and wildlife. Because hydropower is extracting an economic benefit, it has been argued that it should give something back to protect and develop other affected resources. And that can be done. But one of the major socioeconomic conflicts right now is how best to balance the values of environmental resources and hydropower.

How do you put a value on environmental resources?

Coutant: It may seem easy to put a dollar value on a commercially used fish like salmon, but there are complications. We know how much it will sell for in the marketplace. But what is the value of salmon if the fish are not directly consumed? What is the value to somebody who likes to drive up in the mountains and see a free-flowing river and pristine mountains with trout and salmon swimming and spawning instead of a bunch of hydroelectric dams and power lines? That is hard to measure or estimate.

People are willing to pay extra on their electric bills just to know that there is a fish population out there, even though they may never even go fishing or eat these fish. That is a nonuse value, one that should be included to get a representative set of dollar values for costs and benefits. Quite a bit of research still needs to be done to arrive at an acceptable set of procedures for placing resource values on the environmental resources at hydroprojects. For example, the values for each salmon in the Pacific Northwest may range from $10 to $500 to $900 per fish, depending on how you derive the value. There is a lot of controversy in that area because, if the value is low, installing a fish ladder may not be justifiable; if it's high, then a ladder can be justified.

Are there special hydropower issues in other parts of the country?

Coutant: Water allocation in the Central Valley of California is probably the world's stickiest natural resource issue, and hydropower cannot be separated from it.

Sale: One example is an environmental impact statement we have just completed for FERC on a multipurpose hydropower project on the Mokelumne River. The project's primary purpose has been municipal water supply, but because it also produces hydroelectricity, it is licensed by FERC. The project's operators are obligated to protect the fishery resources downstream and to release water to downstream water users--farmers who need irrigation for their food crops. Recently, a higher value has been placed on the protection of the fishery resources than when the project was first developed. So we are doing a reallocation study to determine if more water can be provided to the fish without adversely affecting the other water users in the river basin. That is tough because there is only so much water to go around. The difficulty comes in quantifying the value of water to the different users, including the value of water to the fish.

Coutant: The traditional water allocation system in western states was first come, first served. Anybody who was first to lay a claim to a certain amount of water could pump it out to irrigate crops or meet some other need. Over time, as more and more people laid claims, more water was allocated. Today the new users, like those who want water for East Bay in the San Francisco area, must guarantee that water will be available to those with "prior rights"--the so-called prior or senior users. So more dams have been built to meet these growing needs. Unfortunately, the original allocation didn't include fish uses at all. It is only recently that instream flows have been established to protect fish species that are nearing extinction.

How many projects are you concerned with in the Pacific Northwest and in California?

Sale: In the Pacific Northwest, we are working on 17 FERC licensing projects. We have nine small diversion projects in the Skagit River Basin and seven in the Nooksack River Basin plus the relicensing of a large project on the Skagit River. These small projects in Washington will each produce about 5 megawatts of electricity. In California, we have an assessment for a license renewal on a large project on the Mokelumne River and a similar project on the Tuolumne River. We're also involved with some projects in the upper Mokelumne River Basin. One is a reservoir and the other deals with the proposed renewal of a hydropower license for the operation of nine small dams by the Pacific Gas and Electric Company.

In California, we are also evaluating changes in the operation of one large dam--the New Don Pedro Project on the Tuolumne River. This project supplies drinking water to the city of San Francisco and the two largest irrigation districts in the country, the Modesto and Turlock irrigation districts.

What kind of research is the Laboratory doing in support of environmental mitigation for hydropower projects?

Sale: Our most important current project is the Environmental Mitigation Study for DOE. We have conducted a survey around the country to see what mitigation schemes have been used and to determine which ones work well and which ones don't. We have published a report on our findings.

We have asked for DOE support in developing standardized designs for fish baskets and intake fish screens to help fish move safely upstream and downstream. In the 1970s, Steve Hildebrand established DOE's Hydropower Environmental Program. In the early 1980s, we conducted field research on fish-habitat relations and managed subcontracts with the U.S. Fish and Wildlife Service on fish mortality in turbines. Jim Loar and Glenn Cada were major contributors to this research.

We would like to do more of the laboratory and field work. Now we're doing a fair amount of computer modeling work, a type of paper study. We're modeling the life cycle of the Chinook salmon using available data. For example, we're determining the effects of various conditions on fish migration, spawning, and egg development. Then by plugging in data on conditions in the Mokelumne River before and after hydropower development, we can predict the effects of the new dams on the fish population.

Unfortunately, sometimes unresolvable problems arise because of the multiple uses of a hydroelectric dam. It may be that, even with environmental mitigation, the harmful impacts to a recreational fishery in a reservoir cannot be eliminated. So then you have to enter a process of trying to strike a balance by determining the best combination of multiple uses in the river. And that is another area where I think we've got some unique expertise here at the Laboratory in dealing quantitatively with multiple objective problems.

Do you have a good example of a case where this balancing was done successfully?

Sale: Yes, in our work in the Ohio River Basin. We dealt with license applications for 26 hydroprojects planned for 500 miles of river. The potential cumulative impacts of these projects included a serious decrease in the river's water quality--specifically, its dissolved oxygen content--and we had to figure out the best combination of the proposed projects that would satisfy the needs for hydropower and protect the environment. So we put together a combination of models in which we simulated the interactions between the dams at different levels of development and then we optimized that development to maximize hydropower production and protect the dissolved oxygen resources of the river. Our conclusions in the environmental impact statement, which were challenged by fish and wildlife resource agencies, were completely upheld in the U.S. appellate court. This was a very important precedent for FERC licensing.

Why did the fish and wildlife agencies challenge you?

Sale: It was basically a policy conflict. Fish and wildlife resource agencies often choose to fight their battles by taking policy positions without providing any technical basis for those positions. In this case, they wanted 100% protection of the water quality and fish resources, even though it would have been impossible to develop any hydropower at that level. Our trade-off analysis using computer modeling demonstrated that it is possible to have both protection of the environment to generally accepted standards and a significant amount of hydropower production at the same time. At first, developers thought we were hard on them, but then they realized that the resource agencies were even tougher and that our recommendations had a sound technical basis and were feasible.

A sad end to this story is that very few of the 16 projects that were licensed will be constructed now because of economic, not environmental, reasons. The developers of these projects cannot get power sales contracts in the region.

What specific studies are being done on environmental mitigation for hydropower?

Sale: The work we're currently doing for the DOE hydropower program is a series of case studies of the environmental benefits and costs of state-of-the-art fish passage facilities. We can go as far as possible to quantify fisheries benefits versus the dollar cost of implementing these protection measures. Unfortunately, even when we pick the best cases in which we're least data-limited, we still are not able to get all the way to any kind of a dollar-dollar trade-off analysis. However, the case studies that we completed in September 1992 show a large range of situations, some of which have very high benefit-cost ratios and some of which have extremely low or zero benefits but very high costs. The case studies demonstrate that we can do a better job of identifying designs that work for specific sites.

What we're trying to do with our case studies is to describe a range of different situations, show the success stories and the failures, and explain why certain measures failed and what might have worked better in most cases. We hope that our report will keep people from reinventing the wheel or making the same mistakes again in the future. We've also identified expensive procedures that should not be implemented until more research and field verification are done.

Who is working with you on quantifying the costs of environmental mitigation?

Sale: The work that we're doing for DOE is a joint effort between ORNL and Idaho National Engineering Laboratory. The engineers at INEL are handling the cost side of the study, and we're working more on the benefit side. Don Jones in the Energy Division is also contributing to the fish passage report that we're working on right now. He is reviewing the procedures for trying to put a resource value on fish populations, as well as a dollar value. That turns out to be a rather controversial problem because a number of different types of values are associated with maintaining a fish population. It is not just the direct use; there are a lot of nonuse values as well.

How are environmental impact statements prepared for hydropower projects?

Sale: Usually we do a statement for each individual project, but FERC has moved toward doing basinwide impact assessments. Because many hydroprojects on river basins are fairly small, FERC tends to lump them together and do one big impact statement on basinwide projects instead of on individual projects. In the late 1980s we did one for the Ohio River basin, and more recently, we prepared impact statements for the Skagit basin and the Nooksack basin, both of which are in the state of Washington. Lumping projects together not only is more efficient but also it forces the government to evaluate the cumulative impacts on a river basin of a number of proposed hydroprojects. We need to look at interactions between projects that might result, say, in water quality deterioration or the blockage of salmon migration.

What are the worst problems faced by developers and operators of hydropower facilities?

Sale: Regulatory uncertainty is a big one. The laws have changed so much in the past few years. Developers who want to try new designs for hydroelectric dams must go through multiple reviews by federal and state agencies to get approval. Hydropower developers have a tough time because they must face a nightmare of federal and state regulations.

Regulatory burdens cause another problem: The mounting cost of the time-consuming process from planning to development to operation. The cost is uncertain because the process takes 6 to 10 years and the rules can change half a dozen times in that period. Also, the developer won't learn all the mitigation requirements that must be met until late in the process. It makes it difficult for a developer to figure the amount of money that must be borrowed and the return on the investment.

A third problem is that the environmental community is hot on the trail of the hydropower developers right now. This is a particularly bad time for the developers, and in many cases, for good reason. The salmon populations are crashing on both the east and west coasts, and everybody is very concerned about it. So there is a lot of pressure on hydropower developers from people who see the dams as villains. Some environmental groups are now trying to put certain rivers under federal protection to stop further hydropower development.

Coutant: In some cases, activists are seeking to actually remove dams that either block fish migrations or slow water flow so much that young salmon migrating downstream can't make it. These efforts have so far led to firm plans for removal of one small dam on the Olympic Peninsula and completion of one test draining of a major federal dam on the Snake River in 1992, with another major test draining planned for 1994. The Snake River dam would not be removed, but the water returned would move like a flowing river during the time the young salmon migrate to the sea. The costs of both removal and drainage are very high. The prospect of more actions like these has the hydropower business very edgy.

Does ORNL ever recommend against a proposed hydroelectric dam?

Sale: Absolutely. Some proposed hydropower projects just should not be built because of their location. Some would have unresolvable problems; for example, they would interfere with fish runs or the cultural practices of Native American tribes. In those cases we recommend to FERC that these projects not be developed. Coutant: What's ironic is that what seems to be a perfect site may turn out not to be right after all. One example in the Northwest is a site that has no resident fish because it is blocked by a waterfall. In terms of fish, it's perfect for a hydropower project. Unfortunately for the developer, the site is a traditional religious area for a Native American tribe. The tribe will not give up its heritage, so the developer will probably have to abandon the project.

What's the bottom line?

Coutant: In many cases, a small investment up front in research will solve many of these problems and save considerable money in the long run. Economists are needed to study some of these questions. Good research conducted hand-in-hand with hydropower developers and equipment suppliers can lead to standardized power plant designs to protect the environment and streamlined licensing actions to encourage the most appropriate hydropower development. Government investment in this type of research at ORNL and elsewhere would be small compared to the payoff. This argument would be especially true if the research and development projects were truly joint ventures among government laboratories, the hydropower industry, and the regulatory agencies.

Sale: I would say three things are needed to keep hydropower among our country's valued energy sources: research and development, education, and streamlined regulation. Progress in all three areas is not occurring as quickly as we would like, but we are moving in the right direction.

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