Physics - Energy Resources

Question 1

What are renewable fuels?

Answer 1

Biofuels
Tidal
Wind
Solar
Hydroelectric

Question 2

What are non-renewable fuels?

Answer 2

Nuclear
Fossil fuels (coal, oil, gas)

Question 3

How does a fossil fuel burning power station work?

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. Coal, oil, and gas are fossil fuels, which are fuels that come from long-dead animals and plants.

Question 4

What are activities that require large energy transfers?

Answer 4

Heating

Question 5

How does a nuclear power station work?

Answer 5

The fuel in a nuclear power station is uranium (or plutonium). The uranium fuel is in sealed cans in the core of the reactor. The nucleus of a uranium atom is unstable and can split in two. Energy is transferred from the nucleus when this happens. Because there are lots of uranium atoms in the core, it becomes very hot. The energy of the core is transferred by a fluid (called the coolant) that is pumped through the core. The coolant is very hot when it leaves the core. It flows through a pipe to a heat exchanger, then back to the reactor core. The energy transferred by the coolant is used to turn water into steam in the heat exchanger. The steam drives turbines that turn electricity generators.

Question 6

How does wave power work?

Answer 6

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 7

How does hydroelectric power work?

Answer 7

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 8

How does tidal power work?

Answer 8

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, electricity is generated by the tidal flow passing through undersea turbines on the sea bed. Underwater cables are used to connect these turbines to the national grid.

Question 9

Why are biofuels considered carbon neutral?

Answer 9

In theory, the carbon that the living organism takes in from the atmosphere as carbon dioxide can balance the amount that is released when the biofuel is burnt.

Question 10

What are some of the problems associated with biofuel use and production?

Answer 10

We can’t make enough by diesel to replace regular diesel because there are not enough vegetable oil crops. Biodiesel can also be made from used fish oil but there isn’t enough of that either. Bio diesel is expensive. A lot of farm land is used up growing the crops needed to produce bio-ethanol. Biogas production slows in cool weather.

Question 11

How does a wind farm work?

Answer 11

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

Question 12

How does a solar cell work?

Answer 12

They absorb the sun’s rays and convert them to electricity.

Question 13

Compare the operation of solar cells with solar heating panels.

Answer 13

They both use the sun for energy however a solar heating panel heats water and solar cells produce electricity. They are both renewable and they are both unreliable depending on the weather.

Question 14

What are solar cells also known as?

Answer 14

Photovoltaic cells

Question 15

What is a source of heating in geothermal systems?

Answer 15

Radioactive decay

Question 16

How does a geothermal power plant work?

Answer 16

The energy transferred from these radioactive substances heats the surrounding rock. So energy is transferred by heating towards the Earth’s surface. Geothermal power stations can be built in volcanic areas or where there are hot rocks deep below the surface. Water gets pumped down to these rocks to produce steam. Then the steam that is produced drives electricity turbines at ground level.
In some areas, buildings can be heated using geothermal energy directly.
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 big eco-buildings, this geothermal heat flow is used as under-floor heating.

Question 17

What are some environmental problems associated with burning fossil fuels?

Answer 17

When coal, oil, or gas is burnt, greenhouse gases such as carbon dioxide are released. The amount of these gases in the atmosphere is increasing, and most scientists believe that this is causing more global warming and climate change. Burning fossil fuels can also produce sulfur dioxide. This gas causes acid rain. Fossil fuels are non-renewable. Sooner or later, people will have used up the Earth’s reserves of fossil fuels.

Question 18

What are methods of reducing damage and reducing the harmful products caused by and in waste products of fossil fuels?

Answer 18

The sulfur can be removed from a fuel before burning it, to stop acid rain. For example, natural gas has its sulfur impurities removed before it is used. Carbon capture and storage (CCS) 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 19

What are the waste products of fossil fuels and nuclear fuels?

Answer 19

Greenhouse gases (carbon dioxide)
Sulfur dioxide
Used fuel rods containing radioactive waste

Question 20

What are the problems with nuclear accidents?

Answer 20

An explosion in a reactor could release radioactive material over a wide area. This would affect this area, and the people living there, for many years.

Question 21

What are some advantages and disadvantages of some renewable energy resources?

Answer 21

Advantages: They will never run out because they are always being replenished by natural processes. They do not produce greenhouse gases or acid rain. They do not create radioactive waste products. They can be used where connection to the National Grid is uneconomical. For example, solar cells can be used for road signs and to provide people with electricity in remote areas.

Disadvantages: Renewable energy resources are not currently able to meet the world demand. So fossil fuels are still needed to provide some of the energy demand. Wind turbines create a whining noise that can upset people nearby, and some people consider them unsightly. Tidal barrages affect river estuaries and the habitats of creatures and plants there. Hydroelectric schemes need large reservoirs of water, which can affect nearby plant and animal life. Habitats are often flooded to create dams. Solar cells need to cover large areas to generate large amounts of power. Some renewable energy resources are not available all the time or can be unreliable. For example, solar power is not produced at night and is affected by cloudy weather. Wind power is reduced when there is little or no wind, and hydroelectricity is affected by droughts if reservoirs dry up.

Question 22

Rank the start up times of various power station.

Answer 22

Longest-Shortest Nucleur, Coal, Oil, Natural Gas

Question 23

Why are some power stations in constant operation whereas others may be switched on and off?

Answer 23

using nuclear and coal-fired power stations to provide a constant amount of electricity (the base load demand)
using gas-fired power stations and pumped-storage schemes to meet daily variations in demand and extra demand in winter
using renewable energy resources when demand is high and when the conditions for renewable energy generation are suitable (e.g., use of wind turbines in winter and when wind speeds are high enough)
using renewable energy resources when demand is low to store energy in pumped storage schemes.

Question 24

What are the costs of some energy resources?

Answer 24

On GoodNotes

Question 25

How are capital costs and running costs estimated?

Answer 25

Capital Costs - in terms of cost per kilowatt of power. Running costs - in terms of cost per kilowatt hour of energy.

Question 26

How are the cost of energy facilities payed for?

Answer 26

They are passed on to consumers through increased fuel bills.

Question 27

How can you reduce your fuel bills?

Answer 27

Through energy-saving schemes such as low-energy light bulbs in your home and improved home insulation which reduces the demand for non-renewable energy resources.

Question 28

What are capital costs, running costs?

Answer 28

Capital cost - to build it, to take it out of use at the end of its working life. Running cost - for fuel and maintenance.