Milica Rakic, Essex DHS
Roberta Tevlin, retired
In order to prevent the worst of climate change, the emission of greenhouse gases (GHGs) has to be reduced as fast as possible. The enormity of this task can look overwhelming and can lead to climate despair. However, we already have the technology we need and a great source of information about this can be found on the website of Project Drawdown
where they provide details of almost 100 solutions.
The goal of Project Drawdown is to show how we can ‘drawdown’ the emission of GHGs and then ‘drawdown’ the amount of these gases that are already in the air. This article shows how you can have your students examine 19 of these solutions which are involved in the production and use of electrical energy. This exercise is a good fit for the electricity unit in grade 9 science, the climate change unit in grade 10 science, the electricity unit in grade 11 university physics, and the energy transformation unit in grade 12 college physics.Project Drawdown
According to the website, Project Drawdown “reviews and analyzes practices and technologies that can reduce greenhouse gas concentrations in Earth’s atmosphere and also are currently available, growing in scale, financially viable, able to have a net positive impact, and quantifiable.”
The last point is key to the work in this lesson. The solutions are quantified, and this means that we can compare the impact and costs of the different solutions. Each solution that they model generates three key values assuming that they are implemented across the globe from 2020 to 2050. Each value is given as a range depending on whether it will provide a 1.5 C, or a 2.0 C temperature rise by 2100.
The first number is ‘CO2
Equivalent Reduced/Sequestered’. This number shows how many gigatons less CO2
will result, either because less was emitted, or because some was removed. It is given in ‘CO2
equivalent units’ because the reduction may be in some other GHG, like methane. It is perhaps not surprising that the most significant reductions can come from wind and solar voltaic generation. Some of the other details are less predictable. In their model the CO2
reduction from onshore wind generation is ten times that of offshore wind. This is because the offshore wind utilities need to be in fairly shallow coastal waters and there is less shallow offshore area compared to land. Their model also shows that large solar farms will remove four times as much CO2
as small-scale versions — like solar panels on roofs.
The second number is the ‘Net First Cost to Implement’. The word ‘net’ is very important. It looks at the cost of the new technology compared to the cost of continuing with the old one. As a result, the Net First Cost can be negative! One example of a negative cost can be seen with LED lights. The value is because the cost of purchasing LED lights over the three decades will be less than if incandescent bulbs continued to be used. LEDs last much longer and their cost is expected to drop even more than it has already. Similarly, electric vehicles have a negative value for Net First Cost. This is because the cost of purchasing an electric car has been steadily decreasing and will soon be cheaper than a gas car.
The third number is the ‘Lifetime Net Operational Savings’. This number is also negative for LEDs and electric vehicles because they are more efficient and cost less to run. In fact, almost all of the solutions in the electricity sector save money in the long run. The one example that ends up costing much more is Concentrated Solar Power. This is the technology that uses huge mirrors to focus sunlight on a tower to heat water to steam, to drive a turbine. It is effective, but expensive.
We have made a table of these three values for 19 different solutions in the electricity sector. This table can be found in the file called ‘Greening Electricity Table - Student Version
’ (note: rather than providing a range, we used the mid-value for each). Analyzing this table can be done by the students in small groups and will take two full classes. Comparing Strategies
The solutions in greening electricity can be grouped into three main strategies.
- Generate electricity using processes that don’t emit carbon dioxide; for example, use wind rather than fossil fuel.
- Reduce the need for electricity through more efficient use of electrical energy; for example, insulating buildings and installing smart thermostats.
- Electrify devices that traditionally use fossil fuels; for example, use heat pumps instead of furnaces and electric instead of gas-powered vehicles. This last strategy will increase electricity use, but this won’t increase CO2 emissions as long as the electricity was generated without fossil fuels.
To understand the three strategies, the students are asked to identify which one is being used for each solution with an appropriate colour. Some of the solutions might be new to the students and they can go to the Project Drawdown page for more information.Using Formulas and Conditional Formatting in a Spreadsheet
In order to compare solutions, it would be useful to know not just the costs, but also the costs per gigaton of removed CO2
. You could have your students calculate these values by hand, but this can be really tedious, even if you spread the work out. Instead of doing multiple calculations, we recommend that you use this as an opportunity to introduce or reinforce spreadsheet skills. They can use formulas to generate the costs and savings per gigaton of removed CO2
and also the totals of three values if all 19 solutions are implemented.
The solutions can also be compared more easily if the students use conditional formatting to highlight the best and worst solutions for each criteria. An analyzed version of the spreadsheet can be found in the file ‘Greening Electricity Table - Teacher Version
’. The different colours from the conditional formatting make the electric vehicle and solar voltaic solutions stand out as excellent solutions for a variety of reasons.Comparing Solutions
We have put together a set of questions that guides the students through an examination of the different solutions using this table, the Project Drawdown website, and a few google searches to see what our governments are doing. They look at what are the cheapest solutions, which are the most effective solutions, which are supported by government programs, and so on.
This work will need two classes and the second one will be mostly a work period. The student worksheets for these lessons can be found in the files ‘first half - Student Greening Electricity for grades 9-12
’ and ‘second half - Student Greening Electricity for grades 9-12
’. Detailed answers and extra information for teachers can be found in ‘first half - Teacher Greening Electricity for grades 9-12
’ and ‘second half - Teacher Greening Electricity for grades 9-12
As they work through these questions in small groups, they will see that there are many solutions available. They will learn about what government programs already exist to encourage these solutions and where more needs to be done. This will give them a better idea of what they can do to fight climate change effectively.
Climate change is real, and we have the technological solutions. What we need to do now is to pressure the government to get them implemented.