Electricity

Question 1

How much of fossil fuels is used for one person a year?

Answer 1

10,000 kg

Question 2

How are fossil fuels retrieved?

Answer 2

They are extracted from underground or under the sea bed.

Question 3

What happens inside a power station?

Answer 3

In coal or oil fired power stations and in most gas fired power stations the burning fuel heats water in a boiler. This produces steam. The steam drives a turbine that turns an electricity generator.

Question 4

What are the fossil fuels and how are they made?

Answer 4

They come from long-dead animals and plants.

Question 5

What is an example of biofuels?

Answer 5

Methan gas can be collected from cows or animal manure, from sewage works, decaying rubbish and other sources. This can be used in small gas fired power stations.

Question 6

What is a biofuel?

Answer 6

A fuel taken from living or recently living organisms.

Question 7

Where can biofuels be used?

Answer 7

In modified engines for transport and in generators at power stations.

Question 8

What are some more examples of biofuels?

Answer 8

Biodiesel uses waste vegetable oil and plants such as rapeseed. Other examples of biofuels are ethanol (from fermented sugar cane), straw, nutshells, and woodchip.

Question 9

What is biofuel classified as?

Answer 9

Renewable because it can grow back. It is used at the same rate that it is produced.
Carbon-neutral because it emits the same amount of carbon when burnt that it does when it absorbs it when it grows.

Question 10

Where is the energy from in nucleur fuel?

Answer 10

Atoms

Question 11

How does nucleur fuel work?

Answer 11

Uranium or plutonium atoms are in a sealed can in the core of the reactor. When they collide they split causing more collisions mesning more elctricity is given out creating heat. This heats up water that travels through the coolant to turn water into steam in the heat exchanger. The steam drives turbines that turn electricity generators.

Question 12

How does wind power work?

Answer 12

A wind turbine is an electricity generator at the top of a narrow tower. The force of the wind drives rhe turbine’s blades around. This turns a generator. The power generator increases as the wind speed increases.

Question 13

What is a disadvantage of wind power?

Answer 13

They are unreliable because when there is little or no wind they do not generate electricity.

Question 14

How does wave power work?

Answer 14

A wave generator uses the waves to make a floating generator move up and down. This motion turns the generator so it generates electricity. A cable between the generator and the shoreline delivers electricity to the grid system.

Question 15

What are some disadvantages of wave power?

Answer 15

They need to withstand storms
They dont produce a constant supply of electricity
Lots of cables and buildings are needed which spoil areas of coastline
Tidal flow patterns might also change, affecting the habitats of marine life and birds.

Question 16

How does hydroelectric power work?

Answer 16

Hydroelectricity can be generated when rainwater that’s collected in a reservoir (or water in a pumped storage scheme) flows downhill. The flowing water drives turbines that turn electricity generators at the bottom of the hill.

Question 17

How does tidal power work?

Answer 17

A tidal power station traps water from each high tide behind a barrage. The high tide can then be released into the sea through turbines. The turbines drive generators in the barrage.
In some coastal areas, the tide flows through undersea turbines on the sea bed. Underwater cables are used to connect these turbines to the national grid.

Question 18

What are some facts about solar cell panels?

Answer 18

They are useful we only small amount of electricity is needed like in watches and calculators or in remote places.

they are very very expensive to buy but they cost nothing to run.
lots of them are needed and plenty of sunshine to generate enough power to be useful.

they can be unreliable and areas where the Sun is often covered by clouds

Question 19

What is a solar heating panel and what is it used for?

Answer 19

They heat water that flows through it. On a sunny day, a solar heating pamel on a house roof can supply plenty of hot water for domestic use.

Question 20

How does a solar power tower work?

Answer 20

It uses thousands of flat mirrors to reflect sunlight on a big water tank at the top of a tower. the mirrors on the ground surround the base of the tower. The water in the tank is turned to steam by the heating effect of the solar radiation directed at the water tank. The steam is pipe down to the ground level where it turns electricity generators. The mirrors are controlled by a computer so they can track the sun.

Question 21

What is geothermal energy and how does it work?

Answer 21

It comes from energy released by radioactive substances deep within the earth. The energy transferred from these radioactive substances heats the surrounding rock. So energy is transferred by heating towards the earth’s surtace.

Question 22

Where is the best place to build geothermal power stations?

Answer 22

In volcanic areas or where there are hot rocks deep below the surface. Water gets pumped down these rocks to produce steam. Then the steam that is produced drives electricity turbines at ground level.

Question 23

How can geothermal energy heat a house?

Answer 23

Heat flow from underground is sometimes called ground source heat. It can be used to heat water in long underground pipes. The hot water is then pumped around the buildings. In some eco-buildings, this geothermal heat flow is used as underxfloor heating.

Question 24

What are some fossil fuel problems?

Answer 24

When burning fossil fuels, greenhouse gases such as carbon are released which is causing more global warming and climate change.
They can also produce sulfur dioxide which is the gas that causes acid rain. The sulfur can be reomved from a fuel before burning it for example natural gas has its silphur impurities removed before used to prevent acid rain.
Fossil fuels are non renewable which means they will be used up soon.
Carbon capture and storage technology could be used to stop carbon dioxide emissions into the atmosphere from fossil fuel power stations. Old oil and gas fields could be used for carbon dioxide storage.

Question 25

What are the advantages and disadvantages of nucleur power?

Answer 25

Adv:
No greenhouse gases
Much more energy is transferred

Dis Adv
Radioactive waste has to be stored safely for centuries
An explosion in a reactor could release radioactive material over a wide area. This would affect this areaand the people living there, for many years.

Question 26

What are the advantages of renewable energy sources?

Answer 26

They will never run out
They do not produce greenhouse gases or acid rain
They do not create radioactive waste products.
They can be used in remote areas where the national grid is uneconomical.

Question 27

What are the disadvantages of renewable sources? (6)

Answer 27

They are not currently able to meet the world demand.
Win turbines make noise and some might see them as unsightly.
Tidal barrages affect river estuaries and the habitats of creatures and plants there.
Hydroelectric schemes need large resevoires which have to flood habitats in order to make dams.
Solar cells need to cover large areas to generate large amounts of power.
Some renewable enrgy resources are not available all the time or can be unreliable.

Question 28

What are some reliability problems with renewable enrgy resources?

Answer 28

Hydroelectric - upland resevoir could run dry.
Wind, waves - wind and waves too weak on very calm days.
Tidal - hight of tide varies both on a monthly and yearl cycle.
Solar - no solar energy at night, and variable during the day.

Question 29

How is the variable demand for electricity met?

Answer 29

By using nucleur and coal-fired power stations to provide a constant amount of electricity.
Using gas fired power stations and pumped-storage schemes to meet daily variations in demandand extra demand in winter.
Using renewable energy resources when demand is high and when the conditions for renewable enrgy generation is suitable.
Using renewable energy resources when demand is low to store energy in pumped storage schemes.

Question 30

Start the start up times of each non-renewable resource in order from shortest to longest.

Answer 30

Natural gas
Oil
Coal
Nuclear