2.1 Types of Energy

Here are 9 energy types:
A useful device will transfer one energy type to a type of energy that we desire, but not all the inputted energy will be transferred into the energy type that we desire and some will be lost/ wasted. The wasted energy will be lost into the surroundings. For example, a television turns electrical energy into sound and light. However, some of inputted electrical energy is turned into heat, which is not a desired energy type for a television. Heat and sound energy are often undesirable energy output types. Let’s use another example of a petrolpowered car. A car takes chemical energy (the petrol) and converts it into kinetic energy which is desired. However, it also produces heat and sound energy that are not required and these count as wasted energy.
 Kinetic energy or movement energy
 Heat or thermal energy
 Electrical energy
 Light energy
 Sound energy
 Nuclear energy
 Gravitational potential energy
 Elastic potential energy
 Chemical energy
A useful device will transfer one energy type to a type of energy that we desire, but not all the inputted energy will be transferred into the energy type that we desire and some will be lost/ wasted. The wasted energy will be lost into the surroundings. For example, a television turns electrical energy into sound and light. However, some of inputted electrical energy is turned into heat, which is not a desired energy type for a television. Heat and sound energy are often undesirable energy output types. Let’s use another example of a petrolpowered car. A car takes chemical energy (the petrol) and converts it into kinetic energy which is desired. However, it also produces heat and sound energy that are not required and these count as wasted energy.
Energy Efficiency
A device will be more efficient with the less energy that it wastes. We can work out energy efficiency of the useful device by using the formula:
A device will be more efficient with the less energy that it wastes. We can work out energy efficiency of the useful device by using the formula:
Efficiency = Useful Energy Out / Total Energy In (x 100)
If you do not know the energy inputs and outputs for a machine, but you do know the power inputs and outputs you can still work out the machines efficiency by using the following formula:
Efficiency = Useful Power Out / Total Power In (x 100)
Efficiency in the Home
Households are now more aware of how efficient the products that they use are because of government campaigns. Furthermore, technology has progressed and now firms are able to design more efficient appliances. Many households and firms have installed energy efficient lightbulbs, where the lightbulb uses less energy and light output is the same (less efficient lightbulbs use more energy and this energy is wasted through heat). Also, appliances are now becoming more efficient, and when an appliance is replaced, the new appliance will be more efficient than the old one and will have less of an environmental impact. In addition, consumers are more aware of how energy efficient appliances are because appliances are given an energy rating.
We can also work out the payback time for buying a new appliance. We can do this by using the following formula:
Households are now more aware of how efficient the products that they use are because of government campaigns. Furthermore, technology has progressed and now firms are able to design more efficient appliances. Many households and firms have installed energy efficient lightbulbs, where the lightbulb uses less energy and light output is the same (less efficient lightbulbs use more energy and this energy is wasted through heat). Also, appliances are now becoming more efficient, and when an appliance is replaced, the new appliance will be more efficient than the old one and will have less of an environmental impact. In addition, consumers are more aware of how energy efficient appliances are because appliances are given an energy rating.
We can also work out the payback time for buying a new appliance. We can do this by using the following formula:
Payback Time (in year) = Initial Outlay / Annual Saving
The annual saving will be the amount of money that has been saved by switching to a more efficient appliance. Suppose that I was thinking about purchasing a new TV for £300. This TV was more efficient than my old TV because it uses less electrical energy and it would save me 10 pence per hour of TV that I watch. In a year, I watch 750 hours of TV. How long will my payback period be?
To work this question out we first need to find the annual saving from purchasing this TV. The hourly saving is 10p and I watch 750 hours a year. This gives me an annual saving of £75 (750 x £0.10). To work out the payback time I use the formula above.
To work this question out we first need to find the annual saving from purchasing this TV. The hourly saving is 10p and I watch 750 hours a year. This gives me an annual saving of £75 (750 x £0.10). To work out the payback time I use the formula above.
Payback Time (in year) = Initial Outlay / Annual Saving
Payback Time (in year) = £300 / £75
Payback Time (in year) = 4 years
Payback Time (in year) = £300 / £75
Payback Time (in year) = 4 years
This new TV would give me a payback time of 4 years, which means that after 4 years, the savings that I have made will be more than my initial outlay for the TV.
Sankey Diagrams
A Sankey diagram shows how much energy has been put into an object and how that energy has been used. The useful energy is shown by the horizontal arrow and the wasted energy or useless energy are the arrows that point downwards. The thicker the arrow the more energy is going towards that energy type. Sankey diagrams make it clear that energy cannot be created or destroyed.
Here we have a Sankey diagram for a lightbulb. The thickness of the arrow on the left shows us how much energy the lightbulb is using. The diagram tells us that the lightbulb is taking in 60 J of energy. The lightbulb must give out 60 J of energy because energy cannot be created or destroyed. The lightbulb gives out 7.5 J of light energy (which is the desired energy from a lightbulb) and it also gives out 52.5 J of heat energy (which is wasteful energy that we do not want from a lightbulb).
You could work out the energy efficiency for this lightbulb from the information given. The answer is at the end of the video.
A Sankey diagram shows how much energy has been put into an object and how that energy has been used. The useful energy is shown by the horizontal arrow and the wasted energy or useless energy are the arrows that point downwards. The thicker the arrow the more energy is going towards that energy type. Sankey diagrams make it clear that energy cannot be created or destroyed.
Here we have a Sankey diagram for a lightbulb. The thickness of the arrow on the left shows us how much energy the lightbulb is using. The diagram tells us that the lightbulb is taking in 60 J of energy. The lightbulb must give out 60 J of energy because energy cannot be created or destroyed. The lightbulb gives out 7.5 J of light energy (which is the desired energy from a lightbulb) and it also gives out 52.5 J of heat energy (which is wasteful energy that we do not want from a lightbulb).
You could work out the energy efficiency for this lightbulb from the information given. The answer is at the end of the video.