Friday, January 22, 2010
ENERGY RESOURCES: FOSSIL FUELS 1
What do I need to know?
"Energy Resources" is NOT the same thing as "Types of energy".
"Types of energy" means "kinetic energy", "chemical energy" and so forth.
"Energy Resources" is about ways of getting energy so we can generate electrical power.
Most of the Earth's energy comes from the Sun
Solar power, that's obvious, but the energy in coal originally came from the Sun too. Prehistoric plants stored the Sun's energy in their leaves, and when they died and eventually formed coal seams, that energy was still there. So when we burn coal (or any fossil fuel), we're releasing chemical energy that was stored in plants millions of years ago.
The same goes for Wind and Wave power. Waves occur because of winds, and winds blow because the Sun warms our atmosphere. Warm air tends to rise, and winds are due to other air moving in to replace it.
Most power stations burn coal, oil or natural gas to run the generators. Others use uranium, or the flow of water. Electricity is sent around the country using high-voltage power lines. Nearly all of the power we use comes from large power stations, although some places such as isolated farms, or hospitals, have their own diesel generators
Coal, oil and gas are called "fossil fuels" because they have been formed from the organic remains of prehistoric plants and animals.
How it works:
Coal is crushed to a fine dust and burnt.
Oil and gas can be burnt directly.
The steam that has passed through the power station's turbines has to be cooled, to condense it back into water before it can be pumped round again. This is what happens in the huge "cooling towers" seen at power stations.
Coal provides around 28% of our energy, and oil provides 40%. Mind you, this figure is bound to have changed since this page was written, so check the figures if you want to quote them.
Burning coal produces sulphur dioxide, an acidic gas that contributes to the formation of acid rain. This can be largely avoided using "flue gas desulphurisation" to clean up the gases before they are released into the atmosphere. This method uses limestone, and produces gypsum for the building industry as a by-product. However, it uses a lot of limestone.
Other fossil fuels are being investigated, such as bituminous sands and oil shale. The difficulty is that they need expensive processing before we can use them; however Canada has large reserves of 'tar sands' , which makes it economic for them to produce a great deal of energy this way.
As far as we know, there is still a lot of oil in the ground. But although oil wells are easy to tap when they're almost full, it's much more difficult to get the oil up later on when there's less oil down there. That's one reason why we're increasingly looking at these other fossil fuels.
Vocabulary: St.B.p.35. Prepositions
Writing: St.B-p. 37. An informal letter. We did all the exercises and the layout in detail because for next Thursday you´ll have to give me a similar composition , as if you were the student who goes to a family in Brighton and writes to them a presentation letter.
Reading: Test 1, test 2
Listening: Listenings 1 and 2, listening 3, audio1 , audio 2, audio 3.
Answers to the reading and listening
None of these tests lasted very long and seemed rather easy, al least this is what I can infer for the short time it took you to do them. I´ll see it this weekend when I mark them.
Speaking: A test for those who hadn´t done it the days before.
Homework: finish the photocopy with questions, Wkb.p.28,29, St.B.p. 38,39, It´s a review of unit 3.
On Monday the class will be held in the lab downstairs in front of the secretary office.
Homework: As none of you had done your homework, you´ll have to do it for next Monday: Grammar, unit 28, 115 . I think you you take tings more seriously, otherwise you´ll have problems with your exams. Remember that you can´t complain later as it´s your own responsibility and I´m telling you with plenty of time in advance.
Reading: A multiple choice test
Listening: A multiple choice test about 8 people talikg. Audio. Scripts 1, 2, 3.
Answers to the reading and the listening
I´ll post the answers and exercises in this blog
Reading: St.B.p.48. Understanding information. an exercise about hotel signs.
Vocabulary: St.B-p.48 about expressions related to hotel language.
Reading: St.B.p.116 about choosing a suitable hotel for people with specific characteristics. and p.48 with the description of the hotels.
Homework: Do the grammar units 28,115 and the reading and activities on p.46, 47, all about Henry VIII´s fifth wife.