Syncing the power grid to renewable energy

This exercise is a part of Educator Guide: Geometric Hives and Renewable Energy Sources / View Guide

Directions for teachers

Project the chart “Electricity generation, transmission and distribution” from the U.S. Energy Information Administration’s “Electricity explained: How electricity is delivered to consumers” page for your class. Ask students to start thinking about where their electricity comes from. Then use the websites embedded in the first section, “Where does your electricity come from?,” to explore the questions together during a class discussion.

Have students work with partners or in small groups to answer the graph-related questions in the second section, “Analyzing source data.” Use the third section, “Shifting challenges,”as an assessment, for individual reflection, or in a small group discussion.

Directions for students

Use the graphs and articles provided to answer the following questions as directed by your teacher.

Where does your electricity come from?

1. Visit the U.S. Energy Information Administration website and click on your state or territory to view its profile and energy estimates. Read the “quick facts” and discuss which one you find most interesting about your state.

Student answers will vary. Many quick facts give information about a state’s energy consumption or production compared with other states. Others give information about how sources of net electricity generation have changed over time.

2. Look at the graph below the quick facts and click on the tab labeled “Electricity.” What are the top two largest net electricity generation sources in your state? Give the approximate amount of energy generated by each in April 2023. Provide units with your answer.

In Wisconsin, for example, natural gas-fired energy sources generated about 1,770 thousand MWh and nuclear energy sources generated about 780 thousand MWh.  

3. What does the unit abbreviation MWh stand for? What is its meaning?

MWh stands for megawatt-hours. A megawatt hour means that a million watts of electricity are generated per hour. It’s a measure of electric output or consumption.

4. Open the All Energy Infrastructure and Resources map. Enter your school’s address into the search bar at the top left corner of the map. Discuss the types of energy infrastructure and resources that are around the school (if needed, zoom out until you can see a couple of different types of infrastructure and resources on the map). Check the key in the box on the right side of the page to understand what the lines and symbols on the map mean (power plants, power lines, etc.).

Do the most common energy infrastructures and resources around your school support one of the two largest net electricity generation sources for your state that you found when answering the second question? Explain why or why not. For example, if you find many solar photovoltaic arrays close to your school, was one of the largest net electricity generation sources non-hydroelectric renewables?

Student answers will vary.

Analyzing source data

Read the introduction to the Science News article “How one device could help transform our power grid” and check out the graphs titled “U.S. electricity generation by major energy source” and “Electricity from renewable sources in the United States.” Answer the following questions in your small group.

US Electricity Generation by Major Energy Source from 1950 to present
U.S. Energy Information Administration
Electricity from renewable sources in the United States from 1980 to present
U.S. Energy Information Administration

1. Explain how the top graph relates to the bottom graph.

The first graph shows the number of billion kilowatt-hours of electricity generated by different sources in the U.S. from 1950 until about 2022. Renewable sources are grouped together as one source in the first graph. The second graph provides a breakdown of electricity generated by different types of renewable energy resources from 1980 until 2020.

2. About how much total electricity was generated in the U.S. in 1990? What about in 2020?

Total electricity generated in 1990 was about 3,000 billion kWh, and in 2020 the total was about 3,900 billion kWh.

3. What are some types of renewable energy sources? Based on the types of renewable energy sources you listed and your knowledge of energy sources that are not renewable, how would you define a renewable energy source?

A renewable energy source obtains its energy from a source that is not depleted by use, such as moving water (hydropower), wind (wind power) or the sun (solar power).

4. Approximately how much electricity was produced by wind in 2020? What about solar in 2020? How did these values compare with 2015? Give your answer in billion kWh and as a percentage of the total U.S. electricity generation.

Electricity produced by wind in 2020 was about 320 billion kWh, and 160 billion kWh in 2015. Electricity produced by solar in 2020 was about 120 billion kWh, and 40 billion kWh in 2015. In 2020, wind contributed about 8%, and solar contributed about 3%. In 2015, wind contributed about 4%, and solar contributed about 1%. Electricity from wind doubled from 2015 to 2020, and electricity from solar roughly tripled.

5. Looking at the first graph, what time period saw the largest growth in renewables as an energy source? Looking at the second graph, which renewable sources mainly contributed to this overall growth?

In the first graph, the renewable energy sources are represented by a green area. The largest increase in the width of the green area occurred between 2010 and 2023. The second graph shows a major increase in electricity from wind and solar sources during that same time.

6. Does the first graph support the claim given in the first paragraph of the article, which states that the U.S. is on track to retire half of its coal-fired power plants by 2026? Explain using data from the graph.

The graph indicates that in 2015 about 1,300 billion kWh were produced from coal, and approximately 700 billion kWh were produced from coal in 2020. These data show that the electricity produced by coal decreased by about half from 2015 to 2020. If this rate of decline remains steady, then the U.S. is on track to decrease the amount of electricity produced from coal by half. This decline may correspond to half of all coal-fired power plants being retired.

Shifting challenges

Discuss the following questions within your small group. For more background on the electric grid, read the Science News Explores article “Explainer: What is the electric grid?.”

1. Discuss some challenges of shifting from coal-fired power plants to renewable energy sources.   

Large coal-fired power plants support the smooth functioning of the grid by regulating power output. Newer renewable energy power plants and sources such as solar panels function differently and can’t be used to stabilize the grid. That function needs to be performed by other technologies, such as grid-forming inverters.

2. Revisit the website that gives your state’s profile and energy estimates. On the graph below the quick facts, click on the first tab labeled “Energy Consumption Estimates.” Does your state consume more energy from fossil fuels or from renewable resources? If time permits, explore other tabs that interest you.

For example, Wisconsin produces significantly more energy from fossil fuels than from renewable resources.

3. What recommendations would you give for shifting your state to clean energy? Do you think your state has a need for grid-forming inverters? Why or why not?

Student answers will vary based on state but should recommend that, should their state transition more toward renewable energy sources, they would need to use grid-forming inverters.