Jump to main content

Catch the Wave!

1
2
3
4
5
87 reviews

Abstract

There is a lot of energy that can be harvested from moving water. Energy can be extracted from water rushing over a waterfall and from the regular patterns of the ocean's tides. The energy that propels waves forward in the oceans can also be extracted and used. But can wave energy power plants be built anywhere there is water? In this energy science fair project, you will use ocean buoy data and mathematics to determine which locations along the coasts of the United States can sustain a wave energy power system.

Summary

Areas of Science
Difficulty
 
Time Required
Average (6-10 days)
Prerequisites
You must have a computer with access to the Internet and spreadsheet software, such as Excel. This science fair project requires that you are familiar with spreadsheet software. If you need help learning more about the software, try using the tutorials that are part of the package, or an online tutorial.
Material Availability
Readily available.
Cost
Very Low (under $20)
Safety
No issues
Credits

Michelle Maranowski, PhD, Science Buddies

  • Microsoft® is a registered trademark of Microsoft Corporation.
  • Excel® is a registered trademark of Microsoft Corporation.

This science fair project is based on an activity found at the following website:

Objective

To determine if any locations along the coasts of the United States are appropriate for building wave energy power systems.

Introduction

It's a beautiful day and you're walking along the beach, when an ocean wave hits the shore and almost pushes you over. Just like your high-energy friend who runs over to tag you as "it," moving water also has energy. But from where does this energy in the form of ocean waves come? Waves are generated by disturbances, ranging from underground earthquakes to a boat moving through the water, but the wind is the most common source of waves. The wind causes ripples on the surface of the ocean, but the strength of the wind, the distance in which the wind blows, and the duration of the wind gust all determine how big the ripples will become.

Waves are characterized by their wavelength and their height. Every kind of wave-whether it is a sound wave, a light wave, or an ocean wave-has a crest and a trough. The crest is the highest point of the wave and the trough is the lowest point of the wave. The wavelength is the distance between two consecutive wave crests. The height is the difference between the wave crest and the next wave trough. Another important characteristic of waves is the wave period. This is defined as the time between two consecutive crests (or troughs) as the crests (or troughs) pass a stationary point. Scientists gather data from the oceans—such as water temperature, wind speed, wind direction, wave height, and wave period—using ocean buoys, which are devices that float in the oceans.



Diagram of wave characteristics such as the crest, trough, wave height, wavelength and still water level

Diagram of a wavelength describes certain characteristics of a wave. The crest is the highest point on the wave while the trough is the lowest point. The difference between the crest and trough is the wave height and the distance between two crests or two troughs is the wavelength.


Figure 1. This figure shows some of the characteristics of a wave. (Courtesy of the Office of Naval Research, 2009.)



As ocean waves move forward, you might think that the water is moving forward; however, this is not the case. The water actually moves in vertical circles and there is little forward motion of the individual water particles in a wave. A wave is just forward motion of energy or momentum.

How can we capture the energy associated with the waves and convert it to something we can use, like electricity? According to the U.S. Department of Energy (U.S. DOE), at any given moment there is enough energy in the oceans' waves around the world to provide up to 2 trillion watts (W) of electricity! Since the oceans will always provide waves, wave energy is a renewable and sustainable form of energy. There are certain parts of the world that are especially rich in wave power. These include the western coasts of Scotland, Australia, South Africa and northern Canada. The northeastern and western coasts of the United States are also good locations to extract wave energy.

The U.S. DOE separates wave energy power systems into two categories: onshore systems and offshore systems. Onshore wave energy power devices include oscillating water column, tapchan, and pendulor devices. In an oscillating water column, a partially submerged structure has an opening below the waterline to the ocean. It encloses a column of air on top of a column of water. As the column of water rises, due to incoming waves, the column of air is compressed and is forced past a turbine. This causes the turbine to rotate and generate electricity. When the wave recedes, the column of air is depressurized and air rushes past the turbine in the other direction. This causes the turbine to rotate again and generate more electricity. When the wave recedes, the column of air is depressurized and air rushes past the turbine in the other direction. This causes the turbine to rotate again and generate electricity. An example of a commercially operating oscillating water column was the LIMPET (Land Installed Marine Powered Energy Transformer) system, originally located on the island of Islay off Scotland's west coast (but shut down in 2013). A tapchan is a tapered channel that feeds into a reservoir that is positioned on a cliff. As a wave enters and proceeds along the tapered channel, its height increases. Eventually, the wave spills over the channel and into the reservoir. The kinetic energy of the wave is converted to potential energy. The generation of electricity is similar to a hydroelectric plant. When water shifts from the reservoir back into the ocean, it is fed through a turbine that generates electricity. A pendulor device is a box with a hinged end that is open to the ocean. As waves pass by the opening, the hinged end swings back and forth. The hinged door is connected to a hydraulic pump and generator. This swinging door causes the generator to create electricity. Offshore wave energy power systems are located where the depth of water is at least 40 meters (m). Examples of offshore wave energy systems are the Salter Duck and the Pelamis systems. Both systems bob up and down, as a result of wave action. The bobbing powers a pump and a generator.

How much energy do these systems generate? The power that the LIMPET system extracts from a wave is expressed in terms of the length of the wave, and is shown in Equation 1.

Equation 1:

J =   0.5 × (HS)2 × TP
  • J is the power in units kilowatt/meter (kW/m).
  • HS is the significant wave height in units of meters (m). The significant wave height is the average wave height of the one-third largest waves.
  • TP is the dominant wave period in units of seconds (sec).

The amount of power produced by the LIMPET system is based on the length of the LIMPET, which is 20 m long. The power produced by the LIMPET system is shown in Equation 2.

Equation 2:

E =   J x 20 m
  • E is the power in units kilowatts (kW).
  • J is the power in units kilowatt/meter (kW/m) and is calculated in Equation 1.

When discussing power consumption, the unit of measure is kilowatt-hour (kWh). To convert the result in Equation 2 to kilowatt-hours, simply multiply by 1 hour (h). If you want to calculate the amount of power generated in a week, simply multiply the power output by the number of hours in a week. For example, the power output of the LIMPET system is 20 kW and the number of hours in a week is 168 h, then the power generated is 20kW x 168 h= 3,360 kWh.

The power produced by a Pelamis system is calculated using a complicated mathematical model. However, knowing the significant wave height and the dominant wave period and using the power matrix derived by the marine power engineers at Pelamis Wave Power, you can arrive at the power produced by the system. The power matrix is shown in Figure 2. The Power period in the matrix is the dominant wave period.



A power matrix used to calculate energy output of an offshore wave energy system

Engineers at Pelamis Wave Power created a color coded chart to determine the power produced by the Pelamis system based on the significant wave height and dominant wave period. The chart is color coded by values, higher values are marked as red and lower values are a light blue.


Figure 2. Power Matrix for the Pelamis offshore wave energy system. (Courtesy of Pelamis Wave Power, 2009.)



In this energy science fair project, you will determine which sites along the coasts of the United States would be appropriate sites to build either an onshore or an offshore wave energy power system.

Terms and Concepts

Questions

Bibliography

This website, from the Office of Naval Research, discusses how ocean waves are formed.

WaveGen, the company that originally designed the LIMPET system, closed in 2013 and their original website is no longer available. However, several publications related to the LIMPET project are still available online:

This is the website of Pelamis Wave Power, the company that manufactures the Pelamis Wave Energy Converter.

This website offers buoy data, which you will need for this science fair project.

  • National Oceanic and Atmospheric Administration's (NOAA) National Data Buoy Center. (2009, March 25). National Data Buoy Center. Retrieved June 6, 2017.

This website contains a large amount of data about electricity generation and consumption in the United States. You can use this site to see how much electricity your state used in a certain year and the sources of the electricity.

  • United States Department of Energy's Energy Information Administration. (n.d.). Electricity. Retrieved June 6, 2017.

Materials and Equipment

Experimental Procedure

  1. To work on this science fair project, you will need access to ocean buoy data. You can access buoy data at the National Oceanic and Atmospheric Administration's (NOAA) National Data Buoy Center page. This website has ocean buoy data from around the world.
  2. A lend on the page should describe the different types of buoys. Some buoys have recent data, and some only have historical data. Not all of the buoys give the data that you need, which are the wave height and the dominant wave period. You will have to investigate the different buoys and see which ones collect the data in which you are interested. Use the on-screen controls and your mouse to move around and zoom in and out of the map. Look for buoys that have Significant Wave Height and Dominant Wave Period listed in the pop-up window, which will appear once you've clicked the buoy. For this project, choose at least three onshore locations and three offshore locations. Note these locations, and the states where they are located, in your lab notebook.
    1. Hints: As you can see on the website's map, there are a lot of buoys, all over the world. To help you begin your search, possible offshore locations could be in one of the Great Lakes. Southern California has multiple onshore locations with wave height and dominant period data, as do locations in Maine and North Carolina.
  3. Begin retrieving and recording data in your lab notebook for your three onshore locations. On the buoy data website, click on a yellow buoy that is producing data. Note the wave height and the dominant wave period and see how it varies over a day, a week, a month, and a year, as follows.
    1. You can look at the daily data by clicking View Details on the pop-up window.
    2. To take a look at historical data, click View History on the pop-up window. You'll see a Historical data bullet, with a Standard meteorological data sub-bullet. Click on the year that you want to look at.
  4. Follow the instructions and import the data from each of the locations into Excel®. If you need help using Excel (or another spreadsheet program), use the tutorials that are part of the software package, or an online tutorial.
    1. Use a new Excel worksheet for each location. Create your own table in each one to organize the data.
    2. To import daily data, simply copy the data directly from the website and paste it into Excel.
    3. To import historical data, use "Method Two" from the website (you'll see this option after you've clicked on a previous year to view). The file will open in another Internet browser window. You can copy and paste the data or save it as a text file. The file is delimited (surrounded) by spaces, so you can then open it in Excel. This file will have a whole year's worth of data, so you can look at various time frames.
  5. Plot the wave height and dominant period data for each of the locations and then see how it varies. Use Equations 1 and 2, from the Introduction, to calculate the potential power generated if there were a LIMPET system built at each of the onshore locations that you chose. Use Excel to plot how the power output varies over a day, over a week, and over a year.
  6. How does the power output vary over a day for each onshore location? What is the highest power output and what is the lowest power output? What is the average power output for a day? Repeat this step for a week, a month, and a year. How does the data over the different time periods compare to each other?
  7. Calculate the amount of power that the systems can provide in a year, in units of kilowatt-hours.
  8. How much power did each of the onshore sites you pick generate? Looking at the data, where would you build an onshore wave energy power system? How many power systems would have to be built, assuming they gave the same amount of power as the original, to provide enough power for the state you live in for one year? You can look up information about electrical power consumption in the United States at the U.S. Department of Energy's Energy Information Administration's website.
  9. Repeat steps 3–8 for each of the three offshore locations. Use the wave height, the dominant period, and the power matrix from Figure 2 to determine the power a Pelamis system could generate if one were placed at the locations you picked.
  10. Reviewing your data and calculations, is wave energy a viable source of energy?
icon scientific method

Ask an Expert

Do you have specific questions about your science project? Our team of volunteer scientists can help. Our Experts won't do the work for you, but they will make suggestions, offer guidance, and help you troubleshoot.

Global Connections

The United Nations Sustainable Development Goals (UNSDGs) are a blueprint to achieve a better and more sustainable future for all.

This project explores topics key to Affordable and Clean Energy: Ensure access to affordable, reliable, sustainable and modern energy.

Variations

  • Look at ocean data from the coasts of other countries. Are there other sites that could serve as locations for wave energy power systems?

Careers

If you like this project, you might enjoy exploring these related careers:

Career Profile
Hydrologists examine the physical characteristics, distribution, and circulation of water above and below the earth's surface. They study rainfall and other precipitation, the paths precipitation takes through the soil and rocks underground, and its return to the oceans and air. Often, they specialize in either underground water or surface water. They examine the form and intensity of precipitation, its rate of infiltration into the soil, its movement through the Earth, and its return to the… Read more
Career Profile
Many aspects of peoples' daily lives can be summarized using data, from what is the most popular new video game to where people like to go for a summer vacation. Data scientists (sometimes called data analysts) are experts at organizing and analyzing large sets of data (often called "big data"). By doing this, data scientists make conclusions that help other people or companies. For example, data scientists could help a video game company make a more profitable video game based on players'… Read more
Career Profile
Did you know that about 700,000 gallons of water flow over the famous Niagara Falls every second? Moving water is a great source of renewable energy, and two hydroelectric power plants built upstream from the Canadian side of the falls and one hydroelectric power plant built upstream from the U.S. side of the falls efficiently exploit the energy from all that water. Such hydroelectric plants use turbines, rotors, generators, and other complicated equipment to supply us with electricity for our… Read more

News Feed on This Topic

 
, ,

Cite This Page

General citation information is provided here. Be sure to check the formatting, including capitalization, for the method you are using and update your citation, as needed.

MLA Style

Science Buddies Staff. "Catch the Wave!" Science Buddies, 20 Nov. 2020, https://www.sciencebuddies.org/science-fair-projects/project-ideas/Energy_p031/energy-power/ocean-wave-energy. Accessed 19 Mar. 2024.

APA Style

Science Buddies Staff. (2020, November 20). Catch the Wave! Retrieved from https://www.sciencebuddies.org/science-fair-projects/project-ideas/Energy_p031/energy-power/ocean-wave-energy


Last edit date: 2020-11-20
Top
We use cookies and those of third party providers to deliver the best possible web experience and to compile statistics.
By continuing and using the site, including the landing page, you agree to our Privacy Policy and Terms of Use.
OK, got it
Free science fair projects.