The Future of Hydroelectric Power

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PARTI

Unit 5

E U

Nuclear

Hydro­electric

Gas Turbine

Fossil Fueled Steam

Fig.3.

Average Power Production Expense per kWh

Cost

Hydropower is the most efficient way to generate electricity. Mod-J ern hydroturbines can convert as much as 90% of the available energy into electricity. The best fossil fuel plants are only about 50% efficient! In the U. S., hydropower is produced for an average of 0.7 cents pel kilowatt-hour (kWh). This is about one-third the cost of using fossil fuel or nuclear and one-sixth the cost of using natural gas. Hydropowj er does not experience² rising or unstable fuel costs.

Renewable

Hydropower is the leading source of renewable energy It providej more than 97% of all electricity generated by renewable sources. Oth er sources including solar, geothermal, wind, and biomass account to: less than 3% of renewable electricity production.

Recreation

Reservoirs formed by hydroelectric dams provide many water-basecj recreational opportunities including fishing, water sports, boating and water fowl³hunting. Hydro-operators own a significant amouni of land around many reservoirs that is open to the public for usej including hiking,⁴ hunting, snowmobiling, and skiing. Hydro-oper-. ators provide many recreation facilities at their hydropower project^ including boat landings, swimming beaches, restrooms, picnic ar

Las, fishing piers, hiking and nature trails,⁵ canoe portages, and park­ing facilities.

- отдых; 2 — испытывает; 3 — дичь; 4 — туризм; 5 — дорога через сельскую местность

Say whether you agree or not with the following statements. In case you don't agree say why. Use the following phrases and word combinations:

I believe the thing is

in my opinion to my mind the fact is

to start with

I think

as far as I know

a) Reservoirs formed by hydropower projects support diverse, healthy, and productive fisheries.

b) Hydropower is the most efficient way to generate electricity.

c) Hydropower is the leading source of renewable energy.

Read the text again and give the summary of it.

IT IS INTERESTING TO KNOW

* Read the text and complete the table below.

Much of the fuel produced in Russia is converted to electricity, about three-fourths of which is generated in thermal stations; some two-thirds of thermal generation is from oil and gas. The remaining power output is produced by hydroelectric and nuclear plants. Most of the hydroelectricity comes from huge stations on the Volga, Kama, Ob, Yenisey, Angara, and Zeya rivers. Nuclear power production expanded rapidly before development was checked by the Chernobyl accident. Much of Siberia's electricity output is transmitted to the European region along high-voltage lines.

	In thermal stations	By hydroelectric and nuclear plants
electricity is generated in Russia
^s°me two-thirds of thermal generation is from

Unit 5. Hydropower. Impacts

HYDROPOWER. IMPACTS

• Read the following text. Pay attention to the advantages and disadvantages of hy dropower.

Environmental Impacts

Hydroelectric power plants have many environmental impacts, somj of which are just beginning to be understood. These impacts, howeveJ must be weighed against the environmental impacts of alternatiJ sources of electricity. Until recently there was an almost universal be lief that hydropower was a clean and environmentally safe method d producing electricity. Hydroelectric power plants do not emit any d the standard atmospheric pollutants such as carbon dioxide or sulni dioxide given off by fossil fuel fired power plants. In this respect, hyl dropower is better than burning coal, oil or natural gas to produce elec tricity, as it does not contribute to global warming or acid rain. Similar ly, hydroelectric power plants do not result in the risks of radioactii contamination associated with nuclear power plants.

[ http://www.iclei.org/efacts/globwarm.htm ]

[ http://www.iclei.org/efacts/acidrain.htm ]

[ http://www.iclei.org/efacts/fission.htm ].

A few recent studies of large reservoirs created behind hydro damj have suggested that decaying vegetation, submerged by flooding, maJ give off quantities of greenhouse gases equivalent to those from othej sources of electricity. If this turns out to be true, hydroelectric facilitiel such as the^ames Bay project in Quebec that flood large areas of land might be significant contributors to global warming. Run of the rivej hydro plants without dams and reservoirs would not be a source of thesl greenhouse gases. The most obvious impact of hydroelectric dams il

the flooding of vast areas of land, much of it previously forested or used for agriculture. The size of reservoirs created can be extremely large. The La Grande project in the James Bay region of Quebec has already submerged over 10,000 square kilometers of land; and if future plans are carried out, the eventual area of flooding in northern Quebec will be larger than the country of Switzerland. Reservoirs can be used for ensuring adequate water supplies, providing irrigation, and recre­ation; but in several cases they have flooded the homelands of native peoples, whose way of life has then been destroyed. Many rare ecosys­tems are also threatened by hydroelectric development.

Fig. 4.

Rocky Reach Hydroelectric Project

Large dams and reservoirs can have other impacts on a watershed. Damming a river can alter the amount and quality of water in the river downstream of the dam, as well as preventing fish from migrating up­stream to spawn. These impacts can be reduced by requiring minimum flows downstream of a dam, and by creating fish ladders which allow fish to move upstream past the dam. Silt, normally carried downstream to the lower reaches of a river, is trapped by a dam and deposited on me bed of the reservoir. This silt can slowly fill up a reservoir, decreasing ^{ne ar}nount of water which can be stored and used for electrical genera-ton. The river downstream of the dam is also deprived of silt which fer-

zes ^tne river's flood-plain during high water periods.

Section I. Power

Unit 5. Hydropower. Impacts 35

Bacteria present in decaying vegetation can also change mercury, present in rocks underlying a reservoir, into a form which is soluble in water. The mercury accumulates in the bodies offish and poses a health hazard to those who depend on these fish for food. The water quality of many reservoirs also poses a health hazard due to new forms of bac­teria which grow in many of the hydro rivers. Therefore, run of the river type hydroplants generally have a smaller impact on the environment.

The theoretical size of the worldwide hydropower is about four times greater than that which has been exploited at this time. The actual amount of electricity which will ever be generated by hydropower will be much less than the theoretical potential. This is due to the environmental con­cerns outlined above, and economic constraints. Much of the remaining hydro potential in the world exists in the developing countries of Africa and Asia. Harnessing this resource would require billions of dollars, be­cause hydroelectric facilities generally have very high construction costs. In the past, the World Bank has spent billions of foreign aid dollars on huge hydroelectric projects in the third world. Opposition to hydropow­er from environmentalists and native people, as well as new environ-J mental assessments at the World Bank will restrict the amount of money spent on hydroelectric power construction in the developing countries of the world.

In North America and Europe, a large percentage of hydropower potential has already been developed. Public opposition to large hy­dro schemes will probably result in very little new development of big dams and reservoirs. Small scale and low head hydro capacity will' probably increase in the future as research on low head turbines, and standardized turbine production, lowers the costs of hydroelectric power at sites with low heads. New computerized control systems and improved turbines may allow more electricity to be generated from existing facilities in the future. As well, many small hydroelec-¹ trie sites were abandoned in the 1950's and 60's when the price of oil and coal was very low, and their environmental impacts unrealized. Increased fuel prices in the future could result in these facilities be-1 ing refurbished.

Conclusions

Hydroelectric power has always been an important part of the world's electricity supply, providing reliable, cost-effective electricity, and will continue to do so in the future. Hydropower has environmental im­pacts which are very different from those of fossil fuel power plants. The actual effects of dams and reservoirs on various ecosystems are only now becoming understood. The future of hydroelectric power will depend upon future demand for electricity, as well as how societies value the environmental impacts of hydroelectric power compared to the impacts of other sources of electricity.

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