IntroductionLarge hydroelectric projects account for about 20 per cent of the world's power generation. During the past two decades, major controversies have arisen over the human and environmental impacts of hydroelectric projects like Narmada Project in India, Three Gorges in China and the Great Whale Project in Canada. Against this background, the environmental effects of hydroelectric projects are now part of wider debate on issues in energy policy.
Objectives of the StudyThe project proposed to examine the Canadian experience in establishment and operation of hydroelectric projects from the development and environmental angle.
The issues proposed for closer examination included the following:
Were the Canadians able to tackle the environmental problems associated with hydroelectric projects satisfactorily? If so, how? Do their solutions have any applicability for Kerala or for that matter India, where large hydroelectric projects have become controversial?
Is a shift from large to smaller hydel projects needed? If so, what are the advantages and disadvantages? Is it true that smaller projects would never fulfill the needs of a developing economy?
Is there any need to go slow or abandon large hydroelectric projects? Can non-conventional energy sources be alternatives to hydel power?
Hydel power is crucial for peaking purposes. Would they remain so in future? What is the Canadian experience regarding hydel thermal mix?
The study was to be undertaken with special reference to the Idukki Hydroelectric Project in Kerala State of India. As certain features of the James Bay Projects came closer to that of the Idukki project, comparison is mainly attempted with that project.
It was noticed during the study that integrated resource planning and energy efficiency were getting much attention in Canada in the post phase of construction of the La Grande hydroelectric complex (James Bay Project). Therefore, special attention was paid for study of these issues. The results of that are amplified in the appendices.
James Bay ProjectThe James Bay Project, located in the Canadian province of Quebec, is testimony to the engineering skills of Hydro Quebec. Taken up in 1972, the phase I of the project consisting of three generating stations added more than 10000 MW of installed capacity to Quebec's power grid by 1985. The second phase of the project, which involves construction of six more generating stations, is to add another 5000 MW of capacity. Of this, four have already been commissioned. (The fifth, Laforge-2 is scheduled to be completed next year while the sixth, Eastmain 1, is on hold.) The La Grande 2 generating station, completed under phase I, is one of the World's largest power stations in terms of installed capacity (5328 MW).
The project makes use of the 548-metre drop between the source and mouth of the La Grande River and the average flow of 1700 cubic metres per second. The flow was doubled by diverting the waters of two adjacent rivers, Eastmain and Opinaca, into La Grande.
At each site chosen for generating stations, the dam raised the water level immediately upstream of the powerhouse. The profile of the La Grande River is thus transformed into a very long multi level waterfall. The scale of the dams is monumental. The phase I of the project alone involved construction of 215 dams and dikes-- the longest stretches 4.3 km and the highest reaches 162 metres. The eight reservoirs of both the phases together cover 15873 square km. The land surface flooded by the reservoirs (excluding the areas of water bodies that originally existed) was 11505 square km. The impact of creating such large reservoirs on the water regime and land is obviously tremendous.
Some environmental impacts of the project like the destruction of the shorelines could be predicted while those like mercury pollution could not be anticipated. Since the project area is relatively flat, damming the rivers draining those lands was sure to flood extensive areas of river, lake and forest habitat. The type of forests submerged by the James Bay Project is entirely different from tropical forests submerged by some of the reservoirs in India. The taiga is only 5000 to 9000 years old and its biodiversity is very limited compared to tropical forests. Yet it supports at least 39 mammals. The area is also habitat for more than a dozen species of birds and ten to 20 species of fishes.
Of the submerged area, the most biologically productive and diverse were the narrow strips of shrub vegetation along the banks of the rivers. These supported a number of species such as the ptarmigan, rabbits, birds, beaver, muskrat and moose. The La Grande dams inundated thousands of kilometres of such shoreline habitat. These habitats would not be reestablished owing to unnatural fluctuations of water level in the reservoirs that make it difficult for plants to colonise the banks.
These fluctuations are of a wide range and they reverse the natural patterns. The natural lakes and rivers would be at their highest levels during the spring thaw. On the other hand, reservoirs would be at their lowest level in spring owing to higher generation during winter to meet the demand for heating of interiors of houses and other buildings. These unnatural fluctuations could sound the death knell for species like beaver, which builds its underground shelter on the riverbanks. (The beaver's shelter has an exit into the river below the water level. When the top layers of the river are frozen, it can still reach the waters below for seeking food. If the water level goes down, its exit will be blocked with frozen ice. If the level goes up, its hole would be flooded.)
Another impact of the reservoirs is the truncation of trees by the action of lake ice. The water freezes around partially submerged trees. When the water level drops, the ice sticks to the trunks. The trunks eventually break because of the weight of the ice. This produces huge quantities of debris which are blown by the winds to the shores. These ruin spawning beds, hinder plant growth and block passage for both fish and people.
The James Bay Project involved diversion of two rivers-- the Caniapiscau and Opinaca, into La Grande River. This reduced the water flows down stream of the diversion points. At the same time, the diversions increased the flow through the lakes and rivers of the Caniapiscau Laforge route and the Opinaca Boyd Sakami route through which water is transferred to La Grande. Flow also increased on the lower stretches of the La Grande River. This speeded up the natural process of erosion. As the increased flow was sure to erode the island of Fort George at the mouth of the river, the Cree living there had to be shifted to a new settlement.
The project affected the Crees in a variety of ways. Apart from the loss of their island home, they lost trap lines and fishing zones and faced difficulties in navigating the rivers and obtaining drinking water supplies. While shortage of water in rivers whose flows had been diverted caused difficulties in moving boats up the river, floating wood debris made navigation risky in the reservoirs. Difficulties arose in fishing downstream of the La Grande River because of increased flows and the instability and unnaturally early break up of ice in spring.
The high way built to facilitate the movement of construction materials had profound impact on the Cree community besides the settlement of the Fort George band in permanent houses at Chisasibi. (The high way was initially considered a route that would open Quebec mid north territory for the development of resources, particularly mining, forestry and tourism. The Quebec Government had even set up a separate Corporation for the development of the region. However, with changes in mining produce prices and the difficulty in making forestry operations profitable in the territory, hydroelectric developments soon became the only priority.) The project also accelerated the cross-cultural transplant of life styles and consumption patterns of whites among the Crees. Their life became sedentary.
Hydro Quebec undertook certain mitigative measures to offset the negative impacts of its project on the environment and people. Weirs were built on Eastmain and Opinaca rivers to maintain water levels close to those observed under natural conditions. Most of the quarries, sand pits and construction sites and camps were constructed in areas to be flooded by the reservoirs. Once the work was finished, the contractors took up a major clean up of the location, banked overly steep slopes and loosened the soil to encourage regrowth of vegetation. This was followed by reforestation with trees suited for the territory.
The developers provided compensations running into more than $500 millions to the Crees and Inuits affected by the project under the James Bay and Northern Quebec Agreement and its complimentary agreements. These included compensation paid by the Federal Government for the extinguishment of aboriginal title on the land and royalties.
Idukki ProjectThe Idukki hydroelectric project is located on the Western Ghats of the Indian Peninsula at an altitude of 695 metres above the sea level. The reservoir is formed by three dams-- an arch dam across the Periyar River and a concrete dam across the Cheruthony River and a masonry dam at Kulamavu, upstream of Idukki. The reservoir covers nearly 60 square kilometres and has a catchment of 649 square km. Water from the reservoir is taken down to the underground powerhouse at Moolamattom through an underground tunnel, yielding an average gross head of 2182 feet (665 metres). The project has an installed capacity of 780 MW with firm power potential of 230 MW at 100 per cent load factor.
The project involved diversion of the waters of upper part of Periyar into the Muvattupuzha River. This caused severe drought in areas down stream of the river in summer and reduced fresh water availability for industries located near the mouth of the river. The fresh water regime of Periyar River was in dynamic equilibrium with the estuarine tidal cycle. The impoundment of the dam and diversion of water upset this equilibrium. This led to saline water intrusion into areas where fresh water was available previously.
After impoundment of the dam, hundreds of tremours had been recorded in the Idukki area and most of them are classified as reservoir induced. So far, these tremours have not caused any serious damage. Valley slumpings and slope failures became more common in the area following construction of the dam. A major reason for this was the destruction of the forests during and after the construction. The project opened up the inner forests of Idukki district. This accelerated migration to the area, with the work force of around 6000 itself acting as the nucleus.
The project submerged about 6475 hectares of evergreen and deciduous tropical forests. Besides, the construction of roads, cutting of trees and encroachments led to loss of about 2700 hectares of forests and degradation of the remaining forests. Much of the degradation of forests that has happened over the years is irreversible. Owing to loss of habitat, some reptilian species like the rare terrapin has become extinct or sparse.
The reservoir attracted some species of birds, but the number of some other species went down. During the 1975-1983 period (the first phase of the Idukki project was commissioned in 1976), dense vegetation cover in the surrounding areas went down by 56 per cent and sparse vegetation cover by 37 per cent. The area under agriculture increased by 126 per cent. (These indicate the extent of encroachments that had taken place over the years).
Though the area of forests enfolded by the reservoir was declared a wildlife sanctuary as a mitigative measure, it did not help much in conserving the larger herbivores. It has even been recommended that the sanctuary be denotified as the area is not sufficient for meaningful conservation of wildlife.
The project required the eviction of 759 households (population 4500) including tribals. The impacts on the tribals were similar to that faced by the Cree in the James Bay territory. The tribals originally formed an integral part of forests. Their main occupations were hunting, collection of minor forest produce and shifting cultivation. They lived in simple huts made of materials available in the forests. They were rehabilitated in modern houses. This made them sedentary and forced them to abandon their traditional occupations. Their simple way of life had to give way to modern lifestyle and consumption patterns.
Idukki was proposed as a multi purpose project. The objectives included flood control, pisciculture, forestry, horticulture, tourism development, inland water transport and water for domestic and industrial use. As in the case of James Bay (with regard to mining, forestry etc.), hardly any of these materialised.
Effectiveness of Mitigation MeasuresIn the case of Idukki project, hardly any mitigative measures were undertaken other than efforts by Government agencies to check encroachment and conserve the forests close to the reservoir. But these proved ineffective to a large extend. However efforts to check erosion by planting trees were somewhat effective when attempted properly. This, however, proved to be costly because of wastage of funds and corruption.
The experience with the James Bay Project shows that mitigative measures had their limitations. They proved to be expensive and only marginally effective. It was found that preventive measures were better than mitigative measures. According to the developers themselves, it was ten times easier and cheaper to preserve a habitat from damage than to restore it after damage.
Hydro Quebec has, however, gained much experience and developed certain methods and technologies to manage power projects better. Decisions taken early, while optimising design, regarding major aspects like river diversions, design and location of dams, dikes and tailrace canals were found to avert significant damage. Dikes, for example, have helped to protect productive riparian habitat, valleys and lakes from flooding and erosion. Some of these experiences and technologies could be useful for future projects in India.
Certain impacts like mercury pollution at James Bay and reservoir-induced seismicity in Idukki were unanticipated. And no remedy could be found for them. This highlights the uncertainties associated with the impacts of hydroelectric projects.
Big versus SmallIt has been generally accepted that impacts of some big hydroelectric projects were unacceptably high. Therefore, opinion is gaining ground all over the world that small projects were often (but not always) preferable than big ones. A big project may not be bad just because it is big. (Yet, a big dam would be a big risk-- in terms of return on investments, dam failures, break down of generators etc.). The criteria for judging acceptability should be the sustainability of the project (see appendices). However, there is yet no consensus on what is a sustainable project. For example, James Bay Project is sustainable from the point of view of Hydro Quebec. But it is not so from the point of view of the natives, especially the Cree. (Sustainable development is defined as "development that meets the needs of the present without jeopardising the ability of future generations to meet their needs.")
Small hydroelectric projects have recently become comparatively more attractive to utilities in Canada on account of slow growth in demand. From the environmental point of view, they would be acceptable if the reservoirs are small and normal water levels do not exceed the levels reached when the rivers are in spate. Dr. Robert Goodland of the Environment Department of World Bank suggests that a hydel project, big or small, should be preferred when the ratios of energy that could be generated per oustee and per hectare flooded are comparatively high. (See Appendix I).
Utilities like Ontario Hydro, or for that matter the Kerala State Electricity Board, have in the past repeatedly dismissed the idea of new hydroelectric power from small sites citing them as awfully inadequate sources. But estimates show that they could together replace a big project or two. China's small and mini hydel schemes, numbering more than 90000, serve large sections of rural community. In India, considerable scope exists for small, mini and micro power projects and run of the river schemes along rivers originating in the Himalayas and the Western Ghats. However, it is true that small power projects alone would not suffice to meet increasing demand.
In India, the conventional alternatives to hydroelectric power are diesel, coal or natural gas. (After the full impact of Chernobyl nuclear disaster became known, there is less talk of nuclear energy as a major alternative. Natural gas has the limitation that its reserves are low). Considering India's coal reserves and the fact that it imports petroleum, coal would rank equally with diesel. Though thermal plants using coal used to be highly polluting, modern technologies have helped to bring down pollution to very low levels. However, coal is ranked below oil in the West as it produces a lot of carbon dioxide, a green house gas.
The choice between a hydel project and a thermal project can be dictated by economic factors if all the social and environmental costs are internalised. It is often assumed that thermal power is necessarily costlier than hydel power. However, this assumption is not always correct. Only a proper cash flow analysis would show which one is the most economic.
Typically, a hydel project will require higher expenditures in the early years and the thermal project in the later years. In a simplified way, the choice can be stated in terms of whether higher investment costs of hydroelectricity in the early years are or are not justified by its lower operating costs in the later years.
Several non-conventional alternatives to hydroelectric power are emerging fast. Many countries in the world have wind potential. World wind energy production has exceeded 5 TWh and experience both in India and abroad has shown that wind energy is technically and economically viable. But many are yet to turn to that. Solar energy is becoming an attractive option with drop in prices of solar arrays. It has the advantage that it is totally non-polluting. However, it would take some time for the new technologies to replace the need for hydroelectric power.
It is no secret that consultants, contractors and the bureaucracy of the utilities themselves-- whether it is in Canada or India, lobby for particular course of development that may not be in the best interests of the people. (Ontario Hydro's and Hydro Quebec's failure to consider wind energy in a major way is an example. Similarly, the Kerala State Electricity Board is going slow in tapping the wind potential in the State). Such attitudes have slowed the development of alternatives.
Research is going on the use of hydrogen as a fuel on a large scale. Electricity produced using solar or hydel units is to be used to electrolyse water to produce hydrogen. The hydrogen obtained thus could be ignited to produce energy when required. As the byproduct is water, this process results in no pollution.
Peaking PowerHydroelectric power still reigns supreme as a source for peaking purposes. Thermal and nuclear plants would need long start up times to begin generation. As wind is not steady, it could not be fully dependable unless better technologies for storage of power emerge. This demands maintenance of higher reserves.
In Canada, the efficiency levels of hydroelectric projects are very high-- around 92 per cent. Forced outage rates are very low (around 2 per cent) and duration of maintenance shut downs is only 16 days a year. In the case of Idukki project, the outage rates are increasing and duration of shut downs for maintenance reach up to six weeks a year. Though much of the generating and powerhouse equipment is supplied by Canadian companies, they are not functioning as well as they do in Canada. Three of the six generating units were found to have manufacturing defects. The spherical valves of three units developed leakage. Over the years, several of the instrumentation and equipment have failed. This was despite the fact that the generators were not always on twenty four hour operation as the project is designed for peaking purposes.
Hydel Thermal MixAs to the right kind of mix, opinions vary. In India, a hydel thermal mix of 60:40 has been recommended by planners. However, this is not sacrosanct. Quebec is sourcing 95 per cent of its power from hydel sources. Experts at Hydro Quebec have not thought it necessary to have a higher component of thermal or nuclear power. They have also not gone for other alternatives. A major reason for this is economic. Hydroelectricity is often the cheapest of the available alternatives. However, there is a risk in keeping all the eggs in one basket. A year of poor precipitation can drastically bring down the quantum of energy generated. Hydro Quebec takes care of this eventuality to a great extent by keeping large reserve capacities. This would not be a possible option for utilities in India as they often face shortages in generation and cannot think of having sufficient reserves in the near future.
ConclusionThe saying 'Prevention is better than cure' holds true for mitigation of environmental and human impacts of hydroelectric projects. It would be worthwhile to abandon projects when the environmental and social costs to be paid are high. The main criteria for choice of a project should be its sustainability. It is possible that the alternatives to hydroelectric projects might be worse. Therefore, all options before a State should be considered together to arrive at a choice. (See appendix on Integrated Resource Planning). Big and small projects have their own advantages and disadvantages. But a small project would often be preferable owing to lower risk factors. Non-conventional alternatives would take time to arrive on the scene in a big way. There is resistance to adopting some of these technologies owing to vested interests of those working in the field. It is up to the planners, policy makers and the Government to see that the decisions are proper when public money is involved.
The study was made possible by the fellowship granted by the Shastri Indo-Canadian Institute under its Media Fellowships Programme funded by the Canadian International Development Agency.
Dr. Colin Scott, Associate Professor of the Department of Anthropology, McGill University and Director of the McGill Programme on Aboriginal Government, Research, Economy and Environment (AGREE), Montreal, Canada, guided it.
Hydro Quebec gave much information on its projects and policies to facilitate the study. The Ontario Hydro also supplied information on its hydroelectric projects.
The Chairman of Kerala State Electricity Board, Mr. R. Sivadasan, made the Project Reports and other documents relating to the Idukki Project available for the study.
|Roy Mathew /