Energy Resources and Electricity Generation: Answers

Renewable Energy Resources

Name three different types of renewable energy.

Wind, solar, water and geothermal energy are all renewable energy resources. This means we can use them without worrying about them eventually running out.

What type of energy transfers occur when a wind turbine generates electricity?

Wind turbines use the movement of the wind to turn a turbine which causes a generator to produce electricity. The energy transfers involved are the conversion of kinetic energy into electrical energy.

What are some of the advantages and disadvantages of using wind turbines to generate electricity?

The advantages of using wind energy to generate electricity is that it is a renewable resource so it won’t eventually run out. Unlike the use of fossil fuels, it does not produce any polluting gases such as carbon dioxide or sulfur dioxide. In addition, there are no fuel costs. The disadvantages are that electricity generation is dependent on weather conditions and less energy will be produced on days when the wind is less strong. Some people think that wind farms are ugly and ruin the look of the landscape.

A power plant generates electricity by pumping cold water down into hot, dry rock. Describe the energy transfers at each stage of electricity generation from this resource.

Cold water is pumped underground and heat energy is transferred from hot rocks to the water. As the water is heated, the water molecules gain kinetic energy and move around more. The water evaporates to form steam, which travels upwards through another pipe to return back to the Earth’s surface. The steam gains gravitational potential energy. The steam is used in the power plant to turn a turbine which is connected to an electricity generator (kinetic energy is converted into electrical energy).

Non-Renewable Energy Resources

Why are fossil fuels described as a non-renewable resource?

Fossil fuels include coal, oil and natural gas and are formed from the remains of dead organisms and plants millions of years ago. We refer to them as non-renewable because they will eventually run out if we carry on using them for fuel.

Why does the combustion of fossil fuels contribute to global warming and acid rain?

Burning fossil fuels produces carbon dioxide and sulfur dioxide gases (sulfur is found as an impurity in the fuels which reacts with oxygen). Carbon dioxide is responsible for global warming (the gradual heating of the Earth’s surface) and sulfur dioxide causes acid rain (slightly acidic rainfall which has negative consequences on marine life).

How can the radioactive decay of unstable elements be used to generate electricity?

Unstable nuclei undergo radioactive decay which is when they split apart into two daughter nuclei and release two or three neutrons. The neutrons move and bombard other nuclei, causing them to undergo radioactive decay in a chain reaction. The kinetic energy of the moving neutrons is used to turn water into steam. The steam is used to turn a turbine which is connected to a generator to produce electricity.

Describe the advantages and disadvantages of using nuclear power to generate electricity.

The advantages of nuclear power are that it produces a large amount of energy for a relatively small amount of fuel and it produces no polluting gases, such as carbon dioxide and sulfur dioxide. However, radioactive elements will eventually run out if we keep using them, so nuclear power is a non-renewable method of generating electricity. Accidents, like those which happened in Chernobyl and Fukushima can be catastrophic and result in a large portion of the population being relocated. Furthermore, nuclear power stations are expensive to build and the radioactive waste that it generates needs to be carefully disposed of to avoid environmental contamination.