Environment

Hydropower is clean. It prevents the burning of 22 billion gallons of °il or 120 million tons of coal each year. Hydropower does not pro­duce greenhouse gases or other air pollution. Hydropower leaves be­hind no waste. Reservoirs formed by hydropower projects in Wiscon­sin have expanded water-based recreation' resources, and they suppon diverse, healthy, and productive fisheries. In fact, catch rates are sub­stantially higher on hydropower reservoirs than natural lakes.

Section I. Power Engineering

Unit

4. Hydropower. Facts

И Fuel

И Maintenance I Operation

E U

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:

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.

Unit 5

Unit 5. Hydropower. Impacts

HYDROPOWER. IMPACTS

PARTI

• 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.

3-4661

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.

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