1. UNIT 8 Vocabulary Grammar and functions
Alternative energy sources, i.e. renewable energies
Grammar and functions
Expressing opinion = ORAL PRACTICE
Conditional clauses
Special structures: OTHERWISE/UNLESS/PROVIDED
Integrated practice

2. EXPRESSING OPINION p 102 In my opinion… Personally, I think that…
I'd suggest that…
I (strongly)believe that…
I'm convinced that...
As far as I'm concerned…
As far as I know
I'd like to point out that…
What I mean is…
I'm pretty sure that
I agree with the fact that / with you in …
So do I
If I were you, …..
However… / On the contrary…
Yes, but don't you think…
I'm afraid I have to disagree.
Don't you think it would be better...
I don't agree with …..
That's not entirely true because ….
I don't think that...
The problem with that point of view is that...
Neither do I

3. ORAL INTRODUCTION (p93)
What do you understand by renewable and non-renewable energies?
Which renewable energies do you know? Explain them
Which are the advantages of renewable energies? And those of non-renewable?
Would you like to live near a coal power plant? And near a wind farm? Why (not)?

4. VIDEO: 5 GREEN ENERGIES (p94) http://www. ehow
Have all of them the same age? They have not all been around for the same length of time.
What is the age of Geothermal energy? It has been there since the earth began
Where is it? under ground, it's in the hot rocks below ground.
What can be the depth of these rocks? as much as a kilometer down.
How can we fracture these rocks? by exploding dynamite
What can we do then? pump water down and pump the water back up, and when it comes back up it's hot.
Which kind of energy is the most important one today? biomass,
What is it? plants.
Where do plants get their energy from? the sun using the chlorophyll, the green substance in the leaves.
What does biomass do? It absorbs energy from the sun,
How can we reuse that energy? by turning it into biodiesel
It can be used to replace what? the fuel produced from oil and therefore conserve oil.

5. 5 GREEN ENERGIES (p94)
Where does Hydro energy come from? It is energy from the sun.
What happens to the water in rivers? the water evaporates due to the sun’s energy, it then precipitates into rain and falls into the rivers,
How can we produce electricity? we build dams, put it in turbines and we end up with electric power.
Where is there always wind?. near the coast due to the changing temperature of the sea and the land
What can those winds be used for? drive wind turbines.
What are the components? large propellers on a tall tower and at the top of the tower are turbines, and turbines produce electricity.
What is solar energy based on? silicon technology.
How does it work? When we shine light onto a piece of silicon chip it produces a small electric current, if you put enough of them together you get a lot of energy.
What is the problem? This is quite an expensive form of reusable energy .
What is its main use? in devices which have to be carried around, like on your calculator you only need a small amount of energy.

6. ENERGY CRISIS (p94) Paragraph I
Which do you think those present trends are?
Why will there be a “major crisis”?
What will be the consequences of present trends?
Since means
Find two verbs in this paragraph that are synonyms.
Find a Conditional Clause

7. ENERGY CRISIS (p95)
At present (6), almost all our energy comes FROM fossil fuels (7), i.e. (THAT IS) (8), oil, COAL and natural gas.
The Earth's reserves of fossil fuels have BEEN formed BY/FROM organic matter subjected TO enormous heat and pressure FOR millions of years (9).
But such reserves are finite (10). Because power demand is increasing very rapidly (11), fossil fuels will BE exhausted(12) within a relatively short time.
We can estimate the amount of recoverable fuel under the surface of the Earth (13), and we know the rate at WHICH it is BEING extracted (14).
Fairly (15) simple calculations can therefore determine ITS remaining life (16).
If present trends continue, gas and oil reserves will BE exhausted by the middle of the 21st CENTURY.
Similar estimates (17) about coal reserves suggest a projected supply (18) of years. Of course, long before THESE/FOSSIL fuels are exhausted, demand will greatly exceed supply (19)

8. NOUNS/ADJ from VB NOUNS PRODUCE- Production-producer PRESS- Pressure
ESTIMATE- estimate
SUPPLY- Supply
CONSUME- Consumer-consumption
ADJECTIVES
RECOVER – Recoverable
PROJECT – Projected
SUFFICE- Sufficient
REMAIN- Remaining

9. CONDITIONAL CLAUSES (p96)
IF-CLAUSE MAIN CLAUSE
TYPE 0/I (laws / possibility )
Present Present (laws) = Type 0
Future (possibility)
Modal (may, can, should…)
TYPE II (probability)
Simple Past Conditional
(VB-ED) WERE (WOULD/COULD/MIGHT +INF)
TYPE III (impossibility)
Past Perfect Perfect Conditional
(HAD+PP) (WOULD HAVE + PP)

10. EXER: CONDITIONAL (p97)
If we HAD NOT WASTED the fossil fuels, they WOULD HAVE LASTED longer
We COULD DEVELOP other alternative sources if we SPENT more money on research
If a cold object IS PUT in contact…, the latter DECREASES
Unless actions ARE TAKEN now…, CO2 emissions ….
If nuclear power WERE NOT so dangerous, everybody WOULD AGREE to install nuclear power plants.
If we HAD DEVELOPED other alternative sources, fossil fuels WOULD NOT HAVE RUN OUT so rapidly (III).
If a reactor only LASTS 25 years, in a few years we WILL HAVE hundreds of them stored all over the world. (I)
Electricity WOULDN’T HAVE BECOME a major source … if the relationship between electricity & magnetism HADN’T BEEN DISCOVERED
If we DID NOT EMPLOY fossil fuels in the production of electricity, these materials COULD BE USED to manufacture other valuable things (II)
Lots of radioactivity WOULD REMAIN … if there WERE a nuclear accident (II)
If two magnets ARE BROUGHT together, like charges (WILL) REPEL each other. (I)
The ice caps WOULD MELT DOWN if the temperature of the Earth ROSE 0.5C

11. ALTERNATIVE ENERGY- List Conditionals (p98)
What can we do? DEVELOP ALTERNATIVE SOURCES OF POWER
And we will never succeed UNLESS WE TRY
INSTEAD OF BURNING FOSSIL FUELS we should be concentrating on what? MORE ECONOMIC USES OF ELECTRICITY
Why? BECAUSE ELECTRICITY CAN BE PRODUCED FROM ANY SOURCE OF ENERGY
How would our resources last longer? IF WE DIDN’T WASTE SO MUCH ENERGY
How can you save more energy? BY CONSERVATION THAN YOU CAN PRODUCE for the same money
UNLESS WE DO RESEARCH ON SOLAR ENERGY, WIND POWER, WAVE POWER, TIDAL POWER, HYDROELECTRIC schemes, our FOSSIL FUELS WILL RUN OUT
What are other countries doing? SPENDING MUCH MORE THAN US ON RESEARCH
Don’t forget that ENERGY FROM THE SUN, THE WAVES, THE WIND LASTS FOREVER
We won’t survive UNLESS WE START WORKING ON CLEANER, SAFER SOURCES OF ENERGY

12. CONDITIONAL EXPRESSIONS(p96)
UNLESS = IF + Vb in negative a menos que
PROVIDED/PROVIDING (THAT) = IF and only IF siempre que
AS LONG AS / AS FAR AS = on the condition (that) siempre y cuando, en tanto en cuanto
IN CASE (THAT) = In the event (that)
OTHERWISE= IF NOT o si no, de lo contrario
WHEN can also have a conditional meaning (used in conditional TYPE 0)

13. CONFUSING WORDS
UNLESS + Sentence (S+Vb) = a menos que  AT LEAST = al menos (the least +ADJ = el menos ADJ e.g. the least important)
OTHERWISE + Sentence (S+Vb) = o si no, de lo contrario (IF NOT)  UNLIKE/AS OPPOSED TO + Noun = a diferencia de + N // ON THE CONTRARY= por el contrario
IF + Sentence (S+Vb) = si (condition)  WHETHER + Sentence (S+Vb) = si (o no) (e.g. The use of wind power depends on whether there are strong enough winds in the area (or not)

14. PROVIDED/AS LONG AS – OTHERWISE- UNLESS
Wind power is the most efficient renewable source PROVIDED/AS LONG AS there is a constant wind supply in the area
Nuclear energy is the best alternative UNLESS the safety control systems fail
We cannot avoid using conventional fuels; OTHERWISE it is impossible to meet current power demand
For geothermal energy to become a significant alternative better operation systems should be developed; OTHERWISE heat losses greatly reduce system efficiency
Hydropower is a sustainable way of generating electricity PROVIDED/AS LONG AS there is a large river or lake near the plant
A nuclear power plant must be safe, OTHERWISE radiation could get into the air
Incineration of biomass causes air pollution UNLESS the plant is designed with special filters
Industries would take measures to reduce pollution PROVIDED/AS LONG AS they were not too costly
Scientists have warned that marine life will be irreversibly changed UNLESS CO2 emissions are drastically cut
Electricity should be generated by using alternative energies, OTHERWISE fossil fuels will run out in a few years

15. CONDITIONAL: JOIN (p97)
UNLESS we have safe containers, we cannot dispose of the toxic waste.
IF/ WHEN you release the button, the recording time will be set.
IF more people used public transport, it would be possible to park your car in the city center.
If you had studied harder you would have passed your exam.
IF the temperature rises/rose above 1,000ºC, the boiler will/would explode.

16. TRANSLATION 1 (p98-99)
All countries currently rely heavily on coal, oil and natural gas in order to/so as to/ to obtain their energy
Fossil fuels are non renewable, i.e., they are finite resources that will eventually run out.
By contrast/contrarily to this/on the contrary/unlikely, renewable energy sources -such as/like wind or solar energy-will never end
Most renewable energy comes either directly or indirectly from the sun
Solar energy can be used directly to heat / for heating homes and other buildings, for generating electricity, and for other industrial uses.
The sun's heat also drives the winds whose energy can be captured by means of/with wind turbines
The sun's heat also causes water to evaporate.
When it rains the water is collected in dams and transformed into/to electricity in hydroelectric plants.

17. TRANSLATION 2 (p98-99) Sunlight also causes/(makes) plants to/(ø) grow
The organic matter that forms/composes/makes up those plants is known as biomass.
Biomass can be used to produce electricity, fuels for transportation or chemical products.
Hydrogen is also found in many organic compounds, as well as in water
It is the most abundant element on Earth.
But it does not occur naturally as a gas.
It is always combined with other elements, such as/like oxygen, to make water.
Once separated from another element, it can be burnt as a fuel or converted into electricity

18. TRANSLATION 3 (p98-99)
Not all renewable energy resources come from the sun
Geothermal energy taps the Earth's internal heat for electric power production, and the heating and cooling of buildings. And the energy of the tides comes from the gravitational pull of the moon on the Earth.
In addition to/besides tidal energy, there is the energy of the ocean's waves, which are driven by the tides and the winds.
The sun also warms the surface of the ocean more than the ocean depths, creating a difference in temperature that can be used as an energy source . All these forms of ocean energy can be used to produce electricity.
If all these energies were used more widely our dependence on fossil fuels would decrease significantly.

19. LISTENING (p100) power derived from the sun
they will eventually be exhausted
a huge parabolic mirror (that focuses the sun’s heat onto a small area).
more than 7,232ºF (4,000ºC)
- to raise steam and generate electricity..
- or for scientific research
6. 1,300 moving mirrors (covering an area of 5 acres – about 2 hectares)
7. 2½ million kilowatt-hours of electricity (annually)

20. LISTENING 2 Solar Energy p100
Solar energy is used increasingly FOR DOMESTIC HEATING.
Heat is collected BY EXPOSING A LARGE DARKENED METAL PLATE,
covered with one or more LAYERS OF GLASS, to the sun.
WATER OR AIR IS PASSED THROUGH TUBES attached to the plate
and either circulated through the building OR STORED.
Hot water is stored in INSULATED TANKS.
Hot air is passed through a tank FULL OF ROCKS which hold the heat UNTIL IT IS REQUIRED to warm up air for circulation AROUND THE HOUSE.
Sunlight CAN ALSO BE CONVERTED DIRECTLY INTO ELECTRICITY in a solar CELL,
and there is research into the possibility OF USING SUNLIGHT TO PRODUCE CHEMICAL ENERGY by the same sort of reaction AS PHOTOSYNTHESIS IN PLANTS

21. GRAMMAR REVISION: Solar E (p101)
Today over 90% of our energy comes FROM fossil FUELS, i.e., COAL, OIL and natural gas.
THEY are also important raw materials FOR our CHEMICAL INDUSTRIES
People think we should limit their use AS fuels, OTHERWISE the world´s supplies will soon run OUT
Much research is BEING done on the practical use of the sun FOR heating buildings.
Solar energy is transmitted from the sun, THROUGH space, to the earth AS electromagnetic radiation.
It must BE converted INTO heat before IT can be used.
Various types of solar energy collectors or absorbers are used to convert the sun´s radiation INTO heat.
In a building where a solar system has BEEN installed IT provides water as well AS space heating.
This solar system, based ON water-heating, works LIKE this.
Each of the collectors, placed ON the roof, consists OF a fibreglass tray WHICH/THAT holds a number of copper tubes under a special glass cover.
The tubes are fixed TO a blackened surface WHICH/THAT absorbs energy from the sun.
The sun´s rays passing THROUGH the glass, heat the water IN/INSIDE the tubes.

22. SOLAR ENERGY: reorder (p101)
4- The purpose of any solar system is to collect solar radiation and convert it into useful thermal energy
6- It consists of a number of absorbers or collectors
3- These are made of plates of fiber with copper tubes inside
9- The tubes are connected to a metal surface
2- This surface is black in order to absorb more energy
10- The system works as follows: the sun rays pass through the glass
8- They heat water flowing through the copper tubes
5- When the water is heated it produces steam
1- and the steam is used to move a turbine, which turns a generator
7- This device then transforms heat into electricity

23. VIDEO: 20% RENEWABLE ENERGY (0:30) (p104)
What kind of energy did our grandparents’ watermills and windmills produce? MECHANICAL ENERGY FROM RENEWABLE SOURCES
And the modern versions? ELECTRICITY
What do Windmills do? TRANSFORM WIND INTO ELECTRICITY
What does Hydraulic energy produce? ELECTRICITY
The process is the same in SMALL HYDRAULIC PLANTS and BIG DAMS
The ENERGY POTENTIAL of a head of water is converted INTO ELECTRIC ENERGY
What does Geothermal energy use? HEAT FROM THE DEPTHS OF THE EARTH
What for? TO PRODUCE HEAT AND ELECTRICITY
Solar energy can produce HEAT AND ELECTRICITY
Solar heat panels installed ON A ROOF can cover most HOT WATER NEEDS for sanitary purposes and can serve as backup for DOMESTIC HEATING
What area of solar panels were installed in Europe in 2006? 20 MILLION M2
What do solar mirror plants convert? SOLAR ENERGY INTO ELECTRICITY
How? USING PANELS OF PHOTOVOLTAIC CELLS

24. VIDEO 20% RENEWABLE ENERGY (biomass) (p104)
What is biomass? PRODUCED FROM VEGETAL, ANIMAL OR URBAN WASTE
Which is the most widespread application of biomass? COMBUSTION OF WOOD FOR DOMESTIC HEATING
And in industry or towns? GENERATE HEAT OR ELECTRICITY
How is biogas produced? BY FERMENTATION OF WASTE (e.g. liquid manure used in farms or OTHER ORGANIC WASTE
It is used to produce what? HEAT OR ELECTRICITY
And purified biogas? CAN BE USED AS GASEOUS BIOFUEL
What else does biomass make possible? LIQUID BIOFUELS, BIODIESEL & BIOETHANOL