Energy From Our Oceans
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Problem: Utilizing the unused natural kinetic energy of ocean waves to generate clean, efficient, and reliable electrical energy.
Name: Abhijith Sivaprakash
School: Irvine High School
Teacher: Ms.Sumner
Reference: Image from freepik.com, Surfing Ocean Wave Sunset Ocean Wave Background, accessed 11/24/24
Abstract
Ocean waves possess high kinetic energy, which can be harnessed and converted into electrical energy in many ways. One approach involves Faraday's Law of Electromagnetic Induction. I created a model consisting of a fish tank (representing the ocean) with a wave generator. The prototype I created includes a coil and magnet system, where the floating magnet moves through the fixed coil, inducing an electrical voltage in the coil when its magnetic field is interfered with.
I varied parameters such as coil turns, coil diameter, and wave height to optimize the design for efficiency. The results indicated that a thinner coil with many turns and a lightweight chain of magnets performed best in environments with higher wave activity, producing the highest electrical output. Using Faraday's Law, I scientifically explained the recorded results by assigning values to variables from the real-life model.
My proposed solution successfully demonstrated a practical approach to harnessing wave energy and utilizing its kinetic energy to convert to electrical energy. The prototypes, containing the coil and magnet, can be connected in groups to generate higher voltage and energy, which can be stored in an underwater battery or transmitted offshore. Integrating wave energy into existing power grids and supporting it through government policies and incentives is crucial. Future studies should focus on developing this as a commercial option similar to solar and wind farms. With increased government and industrial support, long-term benefits can be realized, and environmental challenges addressed.
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Introduction (Background Research)
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Energy is one of the main concerns worldwide as of 2024. In California the cost of one kWh is 31.64 cents as of 2024. Energy generation productivity must increase with the growing demand, as energy costs have been steadily increasing by 2.67% each year for the past 25 years across the US3.
While there are several methods to generate energy, all have their own pros and cons. In 2023 fossil fuels generated 60 percent of the U.S.’s energy3, but it produced 36.8 billion metric tons of carbon dioxide7. On the flipside, more “eco-friendly” energy generation methods have the opposite problem. While wind and hydropower generate minimal waste, in 2023 both of those methods combined only generated around 15 percent of the U.S.’s energy3.
However, hydropower may be able to generate the majority of the energy that is needed in the U.S. Upto 2.64 trillion kilowatt-hour of energy may theoretically be produced annually by waves off the U.S. coasts in 2023, which would account for around 63% of all utility-scale electricity output in the country3. There have been various theoretical studies on how we could take the kinetic energy of waves and turn it into electricity, but in order for them to be viable, the method implemented would have to be able to generate a large amount of energy for its cost to install and renew.
Reference: Image from Penn State College of Earth and Mineral Sciences, “U.S. Electricity Generation by Major Energy Source”, 1950-2021
The Engineering Solution, Prototype/Model to be tested.
This prototype’s goal is to generate electrical energy from the reciprocating vertical kinetic energy of waves in the ocean.
It functions by utilizing a coil (which is waterproofed and weighed down) that has a chain of magnets running through it. The magnets are attached to a flotation device, which moves according to the waves. When the water reciprocates vertically because of the waves, the flotation device pulls the magnet chain, making it move in the same way. As the magnet reciprocates through the coil, the magnetic field causes electromagnetic induction in the coil, generating electricity. In the experiment different magnet chain lengths, coil widths, and turns in the coil will be tested to find the optimal proportions for this prototype.
There has been theoretical discussion on the use of these types of devices, yet very few exist in the real world today. The U.S. currently has 0 commercially operating wave energy projects underway, only research projects as of May 23, 20243. So, the results of this project, which tests the effectiveness of a physical model rather than a theoretical one, will give great insight into this topic.
This prototype is stable and consistently generates electricity from ocean waves, so I believe it will revolutionize energy generation if brought to reality.
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Chain
Reference: Image from The Electricity Forum, “Electromagnetic Induction”, accessed 11/13/24
Materials
Wave Tank Setup:
Energy Generation Device:
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Note: The reason for a chain of magnets instead of single magnet is for the convenience of adjusting the height
Procedure
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Water
27.5 cm
vacuum seal
Wave generator
motor
Fish Tank 119 cm * 33 cm * 33 cm
Plastic Board
15 cm * 28 cm
Energy Generation Device
Millivolt Tracker
To carry out a test:
In this engineering project, I changed different variables about the environment and the prototype to see what the optimal conditions were for my prototype.
Variables:
I tested all combinations of these three variables and made a data table to find the conditions in which the most mV is generated.
Results/Data Observations
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Coil Descriptions
Coil 1: thin (2.64 cm diameter), 200 turns.
Coil 2: wide (4.4 cm diameter), 513 turns.
Coil 3:wide (4.4 cm diameter), 200 turns.
Coil 4:thin (2.64 cm diameter), 513 turns.
Results
Coil 4 produced the highest average millivolt output across all tests, 72 mV. Following it, Coil 1 ranked second, with Coil 2 coming in third. Coil 3 generated the lowest average millivolt output.
Average coil mV generated across all tests:
Coil 1: 14.33 mV
Coil 2: 13 mV
Coil 3: 5.67 mV
Coil 4: 38.56 mV
Average magnet chain length mV generated across all tests:
10 cm: 26.42 mV
12 cm: 21.58 mV
14 cm: 5.67 mV
Average wave height mV generated across all tests:
1 cm: 8.17 mV
2 cm: 19 mV
3 cm: 26.5 mV
mV Generated Per Wave at 2 cm Wave Height
mV Generated Per Wave at 3 cm Wave Height
Magnet Chain Length
mV Generated
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mV Generated
Coil 1 Results
Coil 2 Results
Coil 3 Results
Coil 4 Results
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_ = Coil 1 _ = Coil 2 _ = Coil 3 _ = Coil 4
_ = Coil 1 _ = Coil 2 _ = Coil 3 _ = Coil 4
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Magnet Chain Length
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mV Generated
_ = Coil 1 _ = Coil 2 _ = Coil 3 _ = Coil 4
Highest mV Per Wave
mV Generated Per Wave at 1 cm Wave Height
Magnet Chain Length
Discussion
All of the coils had a positive correlation between wave height and mV generated because the magnets distance/time when moving through the coil was increased because the flotation device attached to the magnets was pulled higher.
They also had a positive correlation between the number of turns and mV generated because the change in magnetic flux was multiplied by the number of turns. If one turn made 1 mV from a changing magnetic field, ten turns would multiply that mV output by ten, in this case 10 mV.
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All coils had a negative correlation between coil diameter and mV generated because the further the magnet was from the coil, the weaker the magnetic field strength was when the magnetic field lines intercepted each turn of the coil.
= wide coil distance
from magnet
= thin coil distance
from magnet
All coils had a negative correlation between magnet chain length and mV generated because the longer magnet chains were heavier, making their distance/time less, generating less mV.
One magnet exerts 440 Guass on the thin coil and 90 Gauss on the wide coil
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Reference:
Image from K&J Magnetics Incorporated, Plot of Magnetic Field (In Free Space), accessed 11/20/24
Reference:
Image from K&J Magnetics Incorporated, Plot of Magnetic Field (In Free Space), accessed 11/20/24
Discussion
This is the scientific explanation for how I got the results that I did. It explains why a thinner coil, or a coil with more turns generates more electricity. It also shows how if the magnet travelling through the coil moves at a faster it generates more mV.
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I used Faraday’s Law to find the induced emf (Voltage) in a coil by the movement of a magnet. The formula for Faraday’s Law is ε = -N * (ΔΦ/Δt),
where:
Magnetic flux:
Magnetic flux (Φ) = B * A * cos(θ)* 10-4 webers (Wb)
where:
Scientific Explanation
Let's take an example situation and use Faraday’s law to find the predicted induced EMF in millivolts.
Example situation:
Coil 1 (6.4 cm height * 2.64 cm diameter, 200 turns, 2 layers, wire diameter =0.064 cm)
Magnet Chain Length: 12 cm
Wave Height: 3 cm
Step 1: Calculate Field Strength
Find B at the midpoint coil radius (1.1 cm).
In this case, using figure __ (see slide 8),
B = 440 Gauss (0.044 Tesla) at 1.32 cm (radius of coil) for each magnet.
For 12 magnets, B = 0.528 T (Tesla)
Step 2: Calculate Magnetic Flux
Magnetic flux (Φ) = B * A * cos(θ)
B = 0.528 T
A = πr2 = 5.48 cm2
θ = 0 degrees or 180 degrees, depending on the direction of magnet movement.
Magnetic flux (Φ)= ± 0.000289344 Wb
Step 3: Calculate magnet movement speed
Measure t (rate of change of magnetic flux through the coil)
t = 2 seconds
Step 4: % of Coil in Contact With Magnetic Field
With 12 magnets, only 85% of the coil was in contact with the magnetic field.
Step 5: EMF calculation
ε = ± 200(0.85) * 0.000289344/2 V
ε = ± 0.02459 V = ± 24.59 mV
The recorded data for this example situation was 25 mV, validating these calculations. These calculations can be done for any example situation and will provide near accurate results. The error between the calculated value and the recorded value may be the equipment tolerance, repeatability human error and climate conditions.
Why lower time= +mV
Why a thinner coil = +mV
Why +turns = +mV
Conclusion
The final prototype I designed successfully harnessed wave energy to generate electricity. It utilized a reciprocating energy generation device with a chain of magnets moving through a coil. By testing various variables, I identified the optimal configuration, which produced up to 72 mV per wave. I was able to scientifically explain my results using Faraday’s Law (see slide 9). Understanding the underlying reasons behind these outcomes is crucial for applying, enhancing, and scaling this project effectively.
This project has the potential to be widely implemented in today's society. As clean energy becomes increasingly important, scaling this concept could significantly aid efforts to prevent an environmental crisis. By harnessing wave energy on a larger scale, we can contribute to a sustainable future and make a substantial impact on the global push for clean energy.
The next steps for this project could include testing the final prototype for horizontal movement or exploring new variables. Throughout the project, waterproofing the prototype posed a significant challenge. To bring this system to full-scale production, it would require further refinement to ensure long-term durability for underwater use. This could involve implementing features such as an encapsulating protective case to prevent erosion over time, which could serve as the next progressive step for this project.
This prototype presents wave energy generation as an affordable and feasible solution. The prototype kit costs approximately $25 USD to build and waterproof, not including the cost of a protective case. However, there are additional incidental costs, such as upkeep and repairs due to ocean degradation.
Another important factor to consider is the amount of energy generated. The energy output from this prototype is extremely low compared to the megawatts produced by other established methods. Therefore, scaling up or mass-producing the prototype will be necessary to make a significant impact on energy generation in society, which could substantially increase the project's real-life application costs. Nonetheless, this cost is likely far lower than other forms of energy generation; for example, most wind turbines cost between $2-4 million each2.
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Reference: Image from Alternative Energy Tutorials, ‘Wave Profile Devices’, Accessed 11/20/24
Reflection/Application
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Reference: Image from the U.S. Chamber of Commerce, “2021 Average U.S. Electricity Retail Prices (cents per kWh)”, Accessed 11/13/24
The next steps for researching this problem would be to find more effective ways to waterproof the energy generation system to reduce repair and installation costs. It would also be beneficial to add other forms of energy generation to the prototype, like harnessing the horizontal movement of waves.
As stated before, energy generation is one of society’s main priorities. The energy generated by this prototype, if brought to reality, will greatly benefit coastal states like California, who currently is in the top three states for highest cost per kWh as of 2024 (EIA). If this prototype was realized, depending on its magnet chain length, the coil width and height, the amount of turns, and the intensity of the waves, one could use the results from this experiment and Faraday’s Law to find and prove what the optimal environment and dimensions are for the system.
Incorporating energy from waves into current electrical infrastructure while encouraging it through government rules and regulations and incentives is critical. Storing the energy generated from these devices in underwater battery systems or transmitting the energy offshore may be one way to integrate the energy generated from these devices into society. The government’s aid in this project’s integration into society will also be highly beneficial, whether it be through corporate tax credits, grants and subsidies, or renewable energy certificates for businesses investing in wave energy infrastructure. Long-term solutions to environmental issues can be achieved through enhanced collaboration between governments and industries utilizing the results of this project.
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References Cited
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