Lesson Plan

Teaching Sequence

Work through this resource material in the following sequence:

15 minutes

Tune In: What is efficiency?

20 minutes

Find Out: Energy efficiency of electricity generation

20 minutes

Take Action: Is energy efficiency the whole story?

5 minutes

Reflection

Tune In: What is efficiency?

Step 1

Students will be investigating efficiency to begin this lesson. Pre-prepare a few cups or beakers with the substances listed below. The goal is for students to transfer the substance from one beaker to another. However, each group will be given a different substance, tool to transfer it and number of people to be involved. Each person in the group needs to be involved in a step of the process. For instance, if the group has 1 member, there can be 1 step, if the group has 7 members, there needs to be 7 steps.

Divide students into groups of random numbers. Including a group of 1 and up to a maximum of 7.

Randomly assign each group a substance from the below list and a transfer tool. You can use whatever you have available to you, the goal is to have a varied range of substances and tools.

Substance	Transfer Tool
Water Honey Sand Oil Rocks	Cups Spoons Pipettes/syringes Tongs Sponges

Ask students to think of a way they can most efficiently transfer their substance from the start container to the end container, considering the properties of their substance, tool and how many steps they need in the process.

Step 2

Once students have completed the task, discuss their methods or ask them to write their responses in the student worksheet.

What did the group decide to do? Why?
Was their method efficient? Why/why not?
What were the challenges?
What were the advantages?
What would they change if they could rerun this experiment to make it more efficient?

Explain to students that this experiment simulates how energy is converted from its original form to a usable form through being transferred and transformed. For example, energy is transferred and transformed in a power plant or into electricity to power a light bulb.

Through discussion, students should realise that the efficiency of a process can be affected by the materials you’re dealing with, how many steps are in the process, and the tools you are using to carry out that process. The more steps in the process, the more likely you are to lose some of that energy along the way. If your materials are tricky to deal with, e.g honey, you might not get as much energy out of them at the end.

Step 3

Get students to clean up their experiments before you move on!

Find Out: Energy efficiency of electricity generation

Step 1

Show the following video to your students, which describes energy efficiency and Sankey diagrams:

Energy, Sankey Diagrams, Efficiency | GCSE Physics - vt.physics (https://www.youtube.com/watch?v=vabANWOW6rk)

Explain to students that energy conversions provide us with useful energy, but they can also result in energy transfers or transformations that result in wasted energy. For example, when chemical energy is transformed into electrical energy and then sound and light energy in our phones, it can also produce thermal energy as your phone heats up, which is not useful to us.

An efficient process will ensure that the maximum amount of input energy is turned into the desired output energy.

This efficiency be calculated according to the following equation, you could invite students to write this calculation into their student worksheet:

Efficiency (%) = (useful energy output/total energy input) x 100

This can also be represented as a Sankey diagram, such as the one represented below:

Show this image to your students and discuss what process they think this diagram might represent in terms of efficiency and what energy is wasted/useful. Students can annotate this diagram in their Student Worksheets.

Students should be able to observe that 3 types of energy are being produced: 1 is useful (as there is one arrow pointing to the right), and 2 types are wasted (as their arrows are pointing downwards). A possible example could be an electric fan. The input energy is electrical, and the three outputs are the kinetic energy of the fan (useful), sound energy (wasted), and heat energy (wasted).

Step 2

If your students haven’t watched the following video from the previous lesson, which outlines the process of producing electricity from fossil fuels, you may like to watch it with them now to provide a little more context around the next step:

Power Stations & The National Grid | Electricity | Physics | FuseSchool (https://www.youtube.com/watch?v=A4E35Akk7kM)

Discuss with students how efficient they think this process is. Society relies on fossil fuels for a large amount of our electricity. What does this tell you about the fuel source? Where do they think energy could be lost?

Note: In these sections, we are focusing on the efficiency of generating electricity, considering the methods we currently use and ways to make them more efficient. While efficiency is a crucial factor in determining the effectiveness of a power plant, it's essential to remember that it's not the only factor at play. Efficiency tells us how much useful energy we get from a particular fuel, but it doesn't give us the whole picture. We also need to think about the environmental impact. Some fuels, even if they're efficient at producing energy, can release harmful pollutants like carbon dioxide, sulphur dioxide, or particulate matter into the atmosphere. These pollutants can harm our environment and our health. The Take Action section of this lesson will help to ensure your students understand that it is important to balance efficiency with environmental concerns, resource availability, and sustainability.

Step 3

The following information regarding a coal power plant's efficiency can be found on the Student Worksheet for students to read. Task students with reading about the ways that energy can be lost in a thermal power plant and answering the following questions:

Why is it important to be as efficient as possible in a power plant?
What could be some ways of minimising the energy losses?
What surprised you about this process?
What questions do you have?

Extension Opportunity

Students requiring extension could be tasked with trying to draw a Sankey diagram for the energy conversions in the thermal power plant below. A simplified solution is shown below.

Source: Methods of Improving the Efficiency of Thermal Power Plants - Tongjun Zhang 2020

Take Action: Is energy efficiency the whole story?

Step 1

In the previous lesson in this unit, the different forms of fossil fuel and renewable generated electricity were discussed. If you haven’t completed this lesson, a brief overview of these technologies could be discussed so students have a little more context. Please refer to Lesson 1 for this information.

Divide students into pairs and invite them to explore this webpage from PCI Energy Solutions, which has some information about the efficiencies of different forms of electricity generation (including renewables). Ask them to make note of the most efficient and least efficient energy generation methods.

Prompt students to discuss their findings by asking the following questions:

What surprises them about these figures?
Why do they think these methods have the efficiencies they do?
What did they notice from their initial experiment that might have an effect on the total useful energy we get from a system (eg initial energy source, number of steps in the process, losses along the way)?
Should we only focus on efficiency when we are thinking about the best ways to produce energy?

Step 2

Explain to students that generating electricity without the use of coal and other fossil fuels is extremely important to society to ensure we can lessen our emission of greenhouse gases. To ensure we make the most of our energy generation, it is important to balance environmental factors with efficiency.

Allow students to choose a renewable energy technology that interests them. Their goal is to create a comparison between fossil fuel and renewable energy with the overall goal of recommending a technology that should be used in their state. They can use the table below (included on the Student Worksheet) to help guide their research.

To aid in their research, these are some Renewable energy projects in Australia from the Australian Renewable Energy Agency that students can explore.

	Fossil Fuels	Renewable Technology
Overall Efficiency
Factors that affect efficiency
Advantages
Limitations
Innovations in this technology that impact efficiency and environment
Which method of energy generation do you think society should be using and why?

Optional Extension - What careers would enable less greenhouse gas emissions in the future?

To build upon this knowledge of the projects and technologies that are being used (or could be used in the future) to transition to a net zero economy, students could be tasked with diving a little deeper into the careers that will enable these projects to exist and flourish.

Students can use the document ‘The Million Jobs Plan: Powering jobs, wages and economic growth’, which is available online at: The Million Jobs Plan - Beyond Zero Emissions (bze.org.au)

They can choose one of the sectors they have researched above and use the plan and the internet in order to prepare a job advertisement for a career that this industry needs. It should explain:

The renewable energy and what it is
Where the job will be (where is this project likely to be established?)
The potential growth in the particular industry
How many different types of jobs (and potential numbers) that the industry or industries need
Why it would be a good job to go into for the future

Reflection

What factors should society be considering as we think about ways of generating electricity in the future?
Dive into the future job market of the energy industry. Research and find at least one intriguing job role in the energy sector that didn't exist a decade ago. Share the job title and a brief description of what this role involves.

Energy Efficiency: From Theory to Electricity Generation

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