Ocean+Wave+Generators

=**Introduction: **=

toc The earliest attempt at an ocean wave generator was in 1799 in France by a man named Girard and his son. There wasn’t much progress made on this front until the 1970’s oil crisis, where many countries invested in ocean wave generators to help get away from the reliance on oil. Most of the investments were in Europe and the result of this was over 100 different wave generators were developed in various stages by 2010. The first full scale commercial implementation of linear wave generators was off the coast of Portugal in 2008 and this sparked a curiosity from the world about the potential of ocean wave generators.

 =**Linear Wave Generators: **=

The first design that was developed for ocean wave generators was the “Linear Wave Generator” these work by a large long buoy on top of the water that is connected to a cord. As the waved of the ocean move up and down this causes the buoy to move as well, this causes the cord to be pushed and pulled as the waves move. This cord is then run across the bottom of the ocean with a series on anchors that lead to a power station on the main land, in the station there are a series of generators that are spun with these wires. After that the electricity is then routed to the power grid where it will power people’s homes or any other energy needs.

This is the traditional method when looking at ocean wave generators, the first commercial use of these in 2008 was in Portugal and was 3 generators called [|Pelamis] P-750’s (figure 1.). These were 4 large tubes per generator called ‘ducks’ and these would move up and down with the waves and collect power, they impressively collect almost 90% of the waves energy to produce a total 2.25MW between all three generators. This was enough to power 1,500 Portuguese homes. There was a plan to add another 28 machines to produce a total 22.5MW worst of energy and this would have been about to accommodate 15,000 homes and stop 60,000 pounds of carbon emissions from entering the atmosphere. Unfortunately, there were problems with this design and the generators had to be pulled in after 4 months out in the ocean, it was reported that there were many technical problems, like leakage and damages to the anchor system after the constant motion. This caused an end to this first attempt at commercial wave generators in Portugal because to replace these was too expensive after the 2008 economic crash. Not all was bad with these generators, they collected an impressive amount of energy and were relatively cheap at €8.2m, they were also cheap and easy to fix the smaller issues because most of the parts were off the shelf. It was a good first step, but the damages became too much in the harsh environment of the ocean.

=**MMR Generators: **=

A Mechanical Motion Rectifier ([|MMR]) was the next big breakthrough for the industry, these operate by “a rack-and-pinion and two one-way bearings. The MMR (figure 2.) can transfer the bidirectional motion into unidirectional rotation. In addition, a ﬂy wheel can be integrated into this system to increase the equivalent mass of the engaged system and reduce the speed ﬂuctuation of the generator” [5]. This technology is still in its infancy as the first open ocean small test was in mid-2014. The results of that test were that with a recorded wave height of 0.2 meters and at a depth of 25m there was a peak power output of 205W and an average of 63W power produces after all 3 phases. The results were underwhelming as this was well below the rated power that this machine can handle. There were a couple reasons for this, the first is that the waves on the day of testing were small and could not engage the generator to its full power output, the system was not well tuned, and the boat that the generator was attached too caused some interference with the energy output. This system still has some work to do, but it is showing promise because it is theoretically more reliable and can produce more power than its liner wave brothers.

=**Underwater Wave Generators: **=

The third most common in ocean wave generator technology is the Underwater Wave Generator, the US Air Force is researching into this starting in 2008 and then created the “world’s first free-floating fully submerged wave energy converter” In 2011 thy were able to test out their 1:10 scale model generator in the open ocean, there were a few difficulties with leaks and some electrical problems but once the leaks were addressed the test went as normal, and they even went deeper than they originally planned. They found that they had several survivability issues to figure out. The researchers found that in a simulated wave the generator could absorb 99% of the waves energy and that it is much more efficient than wind energy. Currently wind turbine can only absorb 50-60% of the wind energy that passes through the surface area of the turbine, ocean wave generators can harness anywhere from 90-99% of the wave that passes through them. Once engineers fix them to stay out in the open water longer than 6 months these could be a feasible solution to the energy problem them the world is facing. Currently these get better with every test, so it is only a matter of time until they are all around the world.

This system can withstand the ocean longer because it was underwater as it is away from surface hazards like high winds or storms which have canceled other attempts like the one in Portugal. Their biggest problem is trying to scale the project all the way up to full scale because, as the generator gets bigger and bigger there are more engineering challenges that come up and it becomes harder to assemble and transport to its destination.

=**Conclusion: **=

There has been a few different types of wave generators that have emerged since the 70’s but most of the new styles have come up in the past decade. The linear wave generator is the simplest and most cost-effective design but has the most problems and the submerged system has better efficiency. With more time the linear wave generator will be more popular once engineers find a way to make it stay in the water longer, so it is a worth investment for smaller countries. The MMR design is showing real promise as it is just about as rugged as the other generator format, but its efficiency just isn’t where it needs to be right now. It requires larger waves for the generator to fully engage, so they need to fine tune the machine to work with smaller waves or make it tougher to handle large waves that are out in the ocean. This will all happen there just needs to be more funds invested and we just need to wait as this is a very new design for wave generator. The submerged system has some major engineering challenges, but is the most efficient and can stay out in the ocean longer than the other two major forms of wave generators, like the MMR system there just needs to be more testing and funding to really perfect this system.

=**References: **=

<span style="display: block; font-family: Arial,sans-serif; font-size: 12pt; text-align: right;">1 <span style="font-family: Arial,sans-serif; font-size: 12pt;">Group, T.M.: ‘NASA Energy Concept Could Harness the Power of Ocean Waves - Tech Briefs :: Tech Briefs’, http://www.greendesignbriefs.com/component/content/article/gdm/features/5434, accessed October 2017 <span style="display: block; font-family: Arial,sans-serif; font-size: 12pt; text-align: right;">2 <span style="font-family: Arial,sans-serif; font-size: 12pt;">Prudell, J., Stoddard, M., Amon, E., Brekken, T.K.A., Jouanne, A. von: ‘A Permanent-Magnet Tubular Linear Generator for Ocean Wave Energy Conversion’//IEEE Transactions on Industry Applications//, 2010, **46**, (6), pp. 2392–2400. <span style="display: block; font-family: Arial,sans-serif; font-size: 12pt; text-align: right;">3 <span style="font-family: Arial,sans-serif; font-size: 12pt;">‘Air Force Academy Harnesses Ocean Wave Energy - ProQuest’, https://search-proquest-com.colorado.idm.oclc.org/docview/894151359?pq-origsite=summon, accessed October 2017 <span style="display: block; font-family: Arial,sans-serif; font-size: 12pt; text-align: right;">4 <span style="font-family: Arial,sans-serif; font-size: 12pt;">Cruz, J. (Ed.): ‘Ocean Wave Energy’ (Springer Berlin Heidelberg, 2008) <span style="display: block; font-family: Arial,sans-serif; font-size: 12pt; text-align: right;">5 <span style="font-family: Arial,sans-serif; font-size: 12pt;">Liang, C., Ai, J., Zuo, L.: ‘Design, fabrication, simulation and testing of an ocean wave energy converter with mechanical motion rectifier’//Ocean Engineering//, 2017, **136**, (Supplement C), pp. 190–200. <span style="display: block; font-family: Arial,sans-serif; font-size: 12pt; text-align: right;">6 <span style="font-family: Arial,sans-serif; font-size: 12pt;">‘Detail page’, https://ebookcentral.proquest.com/lib/ucb/detail.action?docID=3020789, accessed October 2017 <span style="display: block; font-family: Arial,sans-serif; font-size: 12pt; text-align: right;">7 <span style="font-family: Arial,sans-serif; font-size: 12pt;">Cadzow, J., Messier, D.: ‘Fort Yukon, Alaska Doe Implementation Grant Gwich’in Solar and Energy Efficiency in the Arctic Final Report’ (Gwichyaa Zhee Gwich’in Tribal Government, Fort Yukon, AK (United States), 2017) <span style="display: block; font-family: Arial,sans-serif; font-size: 12pt; text-align: right;">8 <span style="font-family: Arial,sans-serif; font-size: 12pt;">Gordon, J., Kennedy, D.J., Gordon, J., Hadjerioua, B., Christian, M.: ‘Final Scientific Report: The 45 Mile Hydropower Project Report for the U.s. Department of Energy – Office of Energy Efficiency and Renewable Energy: Wind & Water Power Program’ (Earth By Design, Inc., Bend, OR (United States), 2017) <span style="display: block; font-family: Arial,sans-serif; font-size: 12pt; text-align: right;">9 <span style="font-family: Arial,sans-serif; font-size: 12pt;">Brunelli, D.: ‘A High-Efficiency Wind Energy Harvester for Autonomous Embedded Systems’//Sensors; Basel//, 2016, **16**, (3), p. 327. <span style="display: block; font-family: Arial,sans-serif; font-size: 12pt; text-align: right;">10 <span style="font-family: Arial,sans-serif; font-size: 12pt;">Shields, M.A., Woolf, D.K., Grist, E.P.M., //et al.//: ‘Marine renewable energy: The ecological implications of altering the hydrodynamics of the marine environment’//Ocean & Coastal Management//, 2011, **54**, (1), pp. 2–9. <span style="display: block; font-family: Arial,sans-serif; font-size: 12pt; text-align: right;">11 <span style="font-family: Arial,sans-serif; font-size: 12pt;">Sjökvist, L., Göteman, M.: ‘Peak Forces on Wave Energy Linear Generators in Tsunami and Extreme Waves’//Energies//, 2017, **10**, (9), p. 1323. <span style="display: block; font-family: Arial,sans-serif; font-size: 12pt; text-align: right;">12 <span style="font-family: Arial,sans-serif; font-size: 12pt;">Jacobson, M.Z., Delucchi, M.A.: ‘Providing all global energy with wind, water, and solar power, Part I: Technologies, energy resources, quantities and areas of infrastructure, and materials’//Energy Policy//, 2011, **39**, (3), pp. 1154–1169. <span style="display: block; font-family: Arial,sans-serif; font-size: 12pt; text-align: right;">13 <span style="color: #353535; font-family: Arial,sans-serif; font-size: 12pt;">Hansen B. 2005. Wave Farm Harnesses Ocean’s Energy. Civil Engineering (08857024) 75:28–29. <span style="display: block; font-family: Arial,sans-serif; font-size: 12pt; text-align: right;">14 <span style="font-family: Arial,sans-serif; font-size: 12pt;">[]