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Exercise 2. Make a written translation of the passage of your choice. Ask your group-mate to translate it back to see how adequate your translation was.
Exercise 3. Make a list of key words used in the text. Using the list retell the text.
Text 3
Text A. Energy transportation
While new sources of energy are only rarely discovered or made possible by new technology, distribution technology continually evolves. The use of fuel cells in cars, for example, is an anticipated delivery technology. This text presents some of the more common delivery technologies that have been important to historic energy development. They all rely in some way on the energy sources listed in the previous text.
Electric grids
Electricity grids are the networks used to transmit and distribute power from production source to end user, when the two may be hundreds of kilometers away. Sources include electrical generation plants such as a nuclear reactor, coal burning power plant, etc. A combination of sub-stations, transformers, towers, cables, and piping are used to maintain a constant flow of electricity.
Grids may suffer from transient blackouts and brownouts, often due to weather damage. During certain extreme space weather events solar wind can interfere with transmissions.
Grids also have a predefined carrying capacity or load that cannot safely be exceeded. When power requirements exceed what's available, failures are inevitable. To prevent problems, power is then rationed.
Industrialised countries such as Canada, the US, and Australia are among the highest per capita consumers of electricity in the world, which is possible thanks to a widespread electrical distribution network.
Part B. Energy storage
Methods of energy storage have been developed, which transform electrical energy into forms of potential energy. A method of energy storage may be chosen on the basis of stability, ease of transport, ease of energy release, or ease of converting free energy from the natural form to the stable form.
Energy storage types incude:
Chemical
Some natural forms of energy are found in stable chemical compounds such as fossil fuels. Most systems of chemical energy storage result from biological activity, which store energy in chemical bonds. Man-made forms of chemical energy storage include hydrogen fuel, synthetic hydrocarbon fuel, batteries and explosives such as cordite and dynamite.
Gravitational
Dams can be used to store energy, by using excess energy to pump water into the reservoir. When electrical energy is required, the process is reversed. The water then turns a turbine, generating electricity. Hydroelectric power is currently an important part of the world's energy supply, generating one-fifth of the world's electricity.
Electrical capacitance
Electrical energy may be stored in capacitors. Capacitors are often used to produce high intensity releases of energy (such as a camera's flash).
Mechanical
Pressure:
Energy may also be stored in pressurized gases or alternatively in a vacuum. Compressed air, for example, may be used to operate vehicles and power tools. Large-scale compressed air energy storage facilities are used to smooth out demands on electricity generation by providing energy during peak hours and storing energy during off-peak hours. Such systems save on expensive generating capacity since it only needs to meet average consumption rather than peak consumption.
Flywheels and springs
Energy can also be stored in mechanical systems such as springs or flywheels. Flywheel energy storage is currently being used for uninterruptible power supplies.
Gravitational potential energy storage devices
Energy can be stored by lifting a heavy object vertically using a cable and winch system. Energy can be harvested again by lowering the weight against a dynamo. By using the formula Ug = mgh where 1 Ug is equal to 196 J, and since 1 watt hour = 3600 J it can be determined that an object weighting 1 ton lifted 1 m into the air can store approx. 533 watt hours of energy. Increasing the vertical lift distance to 100 m and the weight to 200 tons leads to a device capable of storing approx. 10.67 mWh of energy.
Thermal
There are several technologies to store heat. Thermal energy from the sun, for example, can be stored in a reservoir or in the ground for daily or seasonal use.
Words to know:
1. evolve
2. anticipate
3. transient
4. blackout
5. brownout
6. excess energy
7. capacitance
8. pressurized gas
9. smooth out
10. flywheel
11. spring
12. winch
Exercise 1. Explain the meaning of the following words and word combinations:
electrical generation plant, transient, blackout, brownout, predefine, per capita, capacitors, vacuum, peak hours, off-peak hours