Renewable Energy

Question 1

Where does biomass energy come from?

Answer 1

Biomass is another word for plants and plants use photosynthesis to convert around 8% of the sunlight falling on their leaves into a carbon based energy store called starch . We can use the starch produced by eating it to power our bodies or by burning them to produce heat. Energy generated from burning wood, plants and other organic matter, such as manure or household waste.

Question 2

Biomass: How is the electricity generated and how is the energy used?

Answer 2

Electricity is made by burning fuel, water getting heated to make steam, the steam turns turbines, the turbine turns generators and electricity is produced. Biomass energy can be used to generate heat for homes and generate electricity.

Question 3

Biomass: Best locations for the resource

Answer 3

Somewhere which produces lots of plant waste.

Question 4

Biomass: Is it reliable?

Answer 4

Biomass is reliable because the supply is predictable and can meet energy demands without disruption.

Question 5

Biomass: advantages

Answer 5

Biomass power stations save on fuel transport costs and reduced the need for landfill.
Waste is used as fuel.
The fuel is usually cheap.There would be less demand on fossil fuels.
Carbon neutral

Question 6

Biomass: disadvantages

Answer 6

The global use of biodiesel is leading to food shortages as poor farmers make more money feeding power stations than people.
It produces fossil fuels since it is burnt.
Some types of waste materials are not available all year round.
Growing and collecting the fuel in sufficient quantities can be difficult

Question 7

Where does geothermal energy come from?

Answer 7

In some parts of the world hot water comes out of the ground so hot that it can be used for power. Some underground rocks are naturally hot while other are heated up by underground lava flows. When water flows over the rocks it is heated and then it returns to the surface as hot water and steam. Deep inside the earth.

Question 8

Geothermal: How is the electricity generated and how is the energy used?

Answer 8

In areas with hot rocks but no water wells are drilled and cold water is pumped down. The hot water or steam that returns up is used to heat homes or drive turbines and generate electricity (however the steam must be purified before).

Question 9

Geothermal: Best locations for the resource

Answer 9

There are no suitable sites for geothermal power stations in the Uk. However, in California, New Zealand, Italy and Iceland geothermal energy is growing in popularity.
Where geothermal energy resources are close to the surface.

Question 10

Geothermal: is it reliable?

Answer 10

Geothermal energy is reliable because it is consistent, efficient and can easily accommodate changes in electricity demand.

Question 11

Geothermal: advantages

Answer 11

Produces no pollution and does not contribute to the greenhouse gas effect.
Power stations do not take up much room and don’t have much of an impact on the environment
No fuel needed
Once the power station is built, the energy is virtually free however some energy might be needed to power the pump

Question 12

Geothermal: disadvantages

Answer 12

There are not many places you can build a geothermal power station because you need rocks of a suitable type at a depth where you can drill down to them.
The type of rocks on the surface must be easily drilled through.
Sometimes geothermal site may “run out of steam” perhaps for decades.
Hazardous chemicals may come up from underground and be difficult to safely dispose of.

Question 13

Where does tidal energy come from?

Answer 13

The gravitational pull of the moon and sun.

Question 14

Tidal: How is the electricity generated and how is the energy used?

Answer 14

By opening a sluice gate at low tide then closing it at high tide you can trap a huge amount of water behind the barrage. By releasing the water through turbines you can drive a generator to make electricity.
Tidal barrages can generate electricity for about 10hrs a day but tidal power stations are only economic where there’s a big tidal range.
Offshore turbines can also be used and are cheaper to build and don’t have the same environmental problems as the barrage.

Question 15

Tidal: best locations for the resource

Answer 15

Where there are big tidal ranges.

Question 16

Tidal: is it reliable?

Answer 16

Even though the energy supply is reliable and plentiful, converting it into useful electrical power is not easy.

Question 17

Tidal: advantages

Answer 17

5. Once it is built tidal power is free.
   No greenhouse gases or waste is produced.
   It produces electricity reliably.
   It isn’t expensive to maintain.
   Tides are completely predictable.
   Offshore turbines and vertical-axis turbines are not ruinously expensive to build and do not have a large environment impact.
   Produces less carbon dioxide than other methods of generating energy

Question 18

Tidal: disadvantages

Answer 18

Power is only provided for approximately 10hrs when the tide is moving in and out
There are few suitable sites for tidal barrages.
A barrage across an estuary is very expensive to build and many miles upstream and downstream are affected. Many birds rely on the tide uncovering the mud flats so that they can feed.
Fish can’t migrate unless “fish ladders” are installed.

Question 19

Where does wind energy come from?

Answer 19

Modern wind turbines capture kinetic energy from the wind and generate electricity.

Question 20

Wind: How is the electricity generated and how is the energy used?

Answer 20

Wind turbines are modern windmills with huge blades mounted on a tall tower. A generator connected behind the blades produces electricity when the wind blows.

Question 21

Wind: best location for resource

Answer 21

Offshore wind farms get higher winds so they are better but they cost a lot more and are more difficult to build
The best places for wind farms are in coastal areas, at the top of rounded hills, open plains and gaps in mountains – places where the wind is strong and reliable.

Question 22

Wind: is it reliable?

Answer 22

No, because the wind isn’t always reliable

Question 23

Wind: advantages

Answer 23

It doesn’t produce any carbon dioxide.
Wind is free, wind farms need no fuel.
Produces no waste or greenhouse gases
The land beneath can usually still be used for farming.
A good method of supplying energy to remote areas.

Question 24

Wind: disadvantages

Answer 24

Wind farms only work when the wind blows and shuts down it blows too hard.
Since the windmills need good wind speed an access to the national grid there are not many places they can be built. The people who live near them. don’t usually like the sound or view.
The wind isn’t always predictable- days with no winds.
Can kill birds-migrating birds tend to like strong winds. Windmills aren’t usually built on migrating routes though.
Can effect television reception if you live nearby.

Question 25

Where does solar thermal energy come from?

Answer 25

The energy comes from the sun rays which have a heating effect on the Earth.

Question 26

Solar thermal: How is the electricity generated and how is the energy used?

Answer 26

In sunny regions with large areas of empty land, mirrors can be used to focus the suns energy into pipes full of water producing enough steam to drive turbines and power generators. It’s not practical to generate electricity like this in the UK but there are many parts of the country where solar panels can be used for domestic heating. If you pump cold water through a solar panel the suns energy will heat it before it returns to the tank, releasing no carbon dioxide. Solar thermal energy produces really hot water in really hot climates but generally need and additional gas or electric boiler to keep the temperature up.

Question 27

Solar thermal: best locations

Answer 27

Solar panels should face south for people in the Northern Hemisphere so that they get direct sunlight. Solar panels work better in places that are exposed to more sunlight and they work better in hotter places.

Question 28

Solar thermal: is it reliable?

Answer 28

Solar thermal can be unreliable if you don’t live in really sunny countries. In the UK, solar power isn’t much use for high-power applications, as you need a large area of solar panels to get a decent amount of power. Also, it only works in the day.

Question 29

Solar thermal: advantages

Answer 29

Solar energy is free and produces no waste or pollution.

In hot countries, solar power can be used when there is no easy way to get electricity to a remote place.

Question 30

Solar thermal: disadvantages

Answer 30

Only works in the day and doesn’t work in the night.

It is very expensive to build solar power stations (although it’s getting cheaper as technology develops).

Question 31

Where does wave energy come from?

Answer 31

The energy comes from the regular wave movement to turn a turbine.

Question 32

Wave: How is the electricity generated and how is the energy used?

Answer 32

2. On the Isle of Isla a wave machine called the limpet forced waves to enter a funnel to drive air past a turbine which turns an electrical generator.
   In Galway Bay in Ireland and offshore generator is undergoing sea trials. The rise and fall of the wave in a floating platform drives air past a turbine to generate electricity.
   Pelamis copies the motion of the sea snake using the rise and fall of the waves to work hydraulic motors driving generators that produce electricity. The energy is used for electricity generation, water pumping etc.

Question 33

Waves: best location for resource

Answer 33

In oceanic regions where wave climates are particularly intense, large offshore power plants will produce a large amount of renewable energy. The areas of the globe with the highest wave energy potential are the North Atlantic, North Pacific and the Southern Ocean.

Question 34

Waves: is it reliable

Answer 34

Wave energy is reliable because waves generate power 24/7.

Question 35

Waves: advantages

Answer 35

The energy is free and there is no waste or fuel needed.
It is not expensive to operate and maintain.
They can produce a great deal of energy.

Question 36

Waves: disadvantages

Answer 36

Must be able to withstand very rough weather.
Needs a suitable site, where the waves are consistently strong.
Depends on the waves – sometimes you will get loads of energy, and sometimes you will get none.
Some designs are noisy but so are waves so any noise is unlikely to be a problem.

Question 37

Where does solar photovoltaic energy come from?

Answer 37

The energy comes from the sunlight.

Question 38

Solar Photovoltaic: How is the electricity generated and how is the energy used?

Answer 38

2. The photovoltaic cell turns sunlight into electricity. When light hits specially treated slices of silicon it releases electrons, this electric flow produces DC electricity which can power lighting and DC appliances. One square meter of solar cells would only generate enough electricity for a 100 watt bulb. Sunlight is a renewable resource and if you put solar cells on your roof you might make some of your own electricity without producing and carbon dioxide. You need to store the electricity in a rechargeable battery so you can use it after dark and convert it to AC so it can power domestic appliances.
   Solar cells are becoming increasingly popular and you could see solar cells replacing roof tiles across the UK.

Question 39

Solar Photovoltaic: best locations for the resource

Answer 39

Places with light winds and hot humidity.

Question 40

Solar Photovoltaic: is it reliable?

Answer 40

Solar photovoltaic power can be unreliable if you don’t live in really sunny countries.

Question 41

Solar Photovoltaic: advantages

Answer 41

Solar energy is free and produces no waste or pollution.
In hot countries, solar power can be used when there is no easy way to get electricity to a remote place.
They are useful for low power uses such as garden lights and battery chargers or for helping your home bills.

Question 42

Solar Photovoltaic: disadvantages

Answer 42

Only works in the day and doesn’t work in the night.
It is very expensive to build solar power stations (although it’s getting cheaper as technology develops).
Solar cells cost a great deal of money compared to the amount of electricity they will produce in their lifetime.

Question 43

Where does hydroelectric energy come from?

Answer 43

The water high up behind a dam across a river valley contains potential energy that can be transformed to kinetic energy.

Question 44

Hydroelectric: How is the electricity generated and how is the energy used?

Answer 44

Electricity is generated releasing the water through a turbine which drives a generator to make electricity. Hydroelectric power stations are easy to maintain and once built they’ll produce electricity for decades.

Question 45

Hydroelectric: best location for the resource

Answer 45

In a valley where there is an existing lake. Along the path of a river, where the river narrows. This enables the collection of the water or the diversion of the river.

Question 46

Hydroelectric: is it reliable?

Answer 46

Hydroelectric energy is reliable because it is more efficient than many other energy sources and can run consistently with little maintenance.

Question 47

Hydroelectric: advantages

Answer 47

Once the dam is built the energy is virtually free.
There is no waste or pollution.
It is more reliable than solar, wind and wave power.
Water can be stored above the damn ready to cope with peaks in demand.
Hydroelectric power stations can increase to full power very quickly.
Electricity can be generated constantly.

Question 48

Hydroelectric: disadvantages

Answer 48

The dams are very expensive to build. However, many damns are also used for flood control or irrigation, so costs can be shared.
Building a large dam will flood a very large area upstream, causing problems for animals that live there.
Finding a suitable site may be difficult since the impacts on the environment and people may be to big.
Water quality and quantity downstream can be affected, which can impact plant life.
Building the dam would release huge amounts of carbon dioxide from the cement and steel used
Floods farmland.
Destroys ecosystems as well as people’s homes.