P1.4 Generating Electricty

Question 1

How is electricity produced in power stations?

Answer 1

Water is heated to produce steam. The steams drives the turbine which is coupled with an electrical generator that produces electricity.

Question 2

Name the fossil fuels

Answer 2

Coal
Oil
Gas

Question 3

What’s a pro of a gas-fired power station?

Answer 3

Hot gases drive the turbine directly which is quicker

Question 4

What’s a biofuel?

Answer 4

any fuel obtained from living or recently living organisms. Some biofuels can be used in small scale, gas fired power stations. They’re renewable sources of energy.

Question 5

What fuel is used in a nuclear power station?

Answer 5

Uranium or sometime plutonium

Question 6

How is energy produced in a nuclear power station?

Answer 6

Nuclear fission

Lots of uranium nuclei so lots of fission reactions take place, releasing lots of energy

Question 7

How do we use energy from wind?

Answer 7

Wind drives turbines

Wind makes them rotate and drive the generator

Question 8

How do we use water to generate electricity?

Answer 8

Falling water, waves or tides can be used.
In a hydroelectric power station water is collected in a reservoir and the water flows downhill which turns turbines at the bottom of the hill. The water is pumped back to the top when the demand for electricity is low.
Waves and tides drive turbines too

Question 9

What’s solar energy?

Answer 9

From the sun, travels through space to the earth as electromagnetic radiation.
Solar cells transfer the energy into electricity and lots of these make a solar panel.
A solar power tower uses thousands of mirrors to reflect sunlight onto a water tank to heat the water and produce steam.

Question 10

What’s geothermal energy?

Answer 10

Produced inside the earth by radioactive processes and this heats the surrounding rock. In volcanic areas, very deep holes are drilled and cold water is pumped down to the hot rocks. It’s heated and comes back to the surface as steam. The steam drives turbines which drive generators, producing electricity.

Question 11

What does non-renewable mean?

Answer 11

It’s eventually going to run out

Eg. Fossil fuels

Question 12

What does sulphur dioxide produce?

Answer 12

Acid rain

Question 13

What are the advantages of coal, oil, gas and nuclear energy?

Answer 13

Coal- bigger reserves and reliable
Oil- reliable
Gas-reliable
Nuclear- doesn’t make polluting gases and reliable

Question 14

What are the advantages of getting energy from water, wind, solar and geothermal energy?

Answer 14

Renewable
No production of polluting gases
Free energy resource
Some are reliable

Question 15

What are the disadvantages of using fossil fuels to produce electricity?

Answer 15

Non-renewable
Produces carbon dioxide - greenhouse gas causes global warming
Produces sulphur dioxide - causes acid rain

Question 16

What’s a disadvantage of using nuclear energy to produce electricity?

Answer 16

Non-renewable
Produces hazardous nuclear wastes, which is difficult to dispose of safely
Small risk of a big nuclear accident

Question 17

What’s the national grid?

Answer 17

A network of cables and transformers that connects power stations to buildings. Our whole country is connected to the network.

Question 18

What’s the national grid’s voltage?

Answer 18

132,000 V or more

Question 19

What voltage do power stations produce?

Answer 19

25,000 V

Question 20

What, in the national grid, changes the voltage before it goes to your home?

Answer 20

Step-down transformers reduce the voltage to 230 V for homes

Question 21

What makes the voltage increase in the national grid for the electricity to travel through the cables?

Answer 21

Step-up transformers

Voltage increases to go through the cables because it reduces the energy wasted, making it more efficient

Question 22

What’s a base load demand?

Answer 22

A constant amount of electricity is provided by nuclear, coal-fired and oil-fired power stations

Question 23

What is start-up time?

Answer 23

The time it takes for a particular energy to start producing electricity

Question 24

What energy resource has the shortest start up time?

Answer 24

Gas

Question 25

What energy source has the longest start-up time?

Answer 25

Nuclear

Question 26

What are the energy transfers in a power station?

Answer 26

Chemical -> thermal -> kinetic -> electrical

Question 27

What’s TV pickup?

Answer 27

It’s an increase in demand for electricity depending what’s on tv, eg. Adverts
If demand is not met, there will be a power cut.

Question 28

What’s decommission?

Answer 28

Nuclear power stations are expensive to build and decommission. It takes as long to build as it would to take down. This increases the price of electricity produced.

Question 29

What’s are the pros and cons of underground cables?

Answer 29

Cons - more difficult to repair, expensive

Pros - can’t see them

Question 30

What are the pros and cons of overhead cabling?

Answer 30

Pros - cheaper, easier to repair and works well

Cons - dangerous to clean, looks ugly, damaged by storms