Where will the prototype be built and tested?
At the moment we are being provided a workspace by a local manufacturer in Zephyrhills Florida, and while small, it is adequate for construction of the turbine prototype and test tank. As we grow we will need to look for a warehouse space near Florida Atlantic University and in close proximity to the Atlantic Ocean.
Additional Technology Information:
We have been asked to provide additional technical details about the turbine and generator. We will be updating this section with ongoing specs and data.
Eco Friendly Generator: The generator module has been specifically designed for the Ocean Energy Turbine. It is the result of eight years of research and testing. Its primary goal is to not create any negative impact on the marine environment. The second goal is to reach the maximum possible efficiency while providing decades of reliable service in a harsh ocean environment. To achieve these goals required development of new technology.
Magnetically Shielded – The Ocean Energy Turbine’s generator is designed to be completely magnetically shielded. This shielding prevents the generator from producing any rotating magnetic fields or transverse electromagnetic radiation that could affect the surrounding marine environment. The power transmission lines are also shielded to prevent electromagnetic radiation. Every effort has been made to ensure the protection of the environment.
Direct drive – By designing around direct drive technology we have greatly reduced the number of moving parts and greatly increased long term reliability. Direct drive drastically reduces service and maintenance intervals resulting in reducing potential down time. Direct drive is also an average of 30% more efficient than conventional transmission and variable torque power generation.
Harmonic Damping – The Ocean Energy Turbine’s generator is designed to have one moving part that is precision balanced for the reduction of harmonic vibration. The absence of brushes, commutators, clutches, gears, and transmissions in the generator design allow the generator to produce maximum power without producing vibrations “noise” that could disturb the marine environment. CrowdEnergy is in the process of filing a number of additional patents covering technologies that are unique to the Ocean Energy Turbine and its generator.
Q: What is the cost of one of those turbines to build and put into water?
A: Crowd Energy would feel more comfortable answering that once we build the mid size turbine and install it at FAU.
Q: Do you anticipate the cost of laying and maintaining power lines to these generators being prohibitive, especially with the corrosive effects of salt water?
A: Not at all. The power transmission technology is the same as use by offshore wind farms which is an existing proven technology. We aren’t rebuilding the car, just the engine.
Q: How are you able to finance such a massive project if your are not supported by the government or a large company?
A: We are building and installing the medium sized production turbine at the Florida Atlantic Open Water Test Station that will allow us to attract enough investment interest to fund construction of the first full size production turbine. At that point we will need government / corporate funding.
Maintenance and Sea Growth?
Q: How will you discourage growth and debris from being caught or jamming the turbines.
A: In the past 10 years there have been great advancements in anti-biofouling non toxic mating coatings for materials susceptible to corrosion.One such coating is nano-carbon composite that creates a surface that marine organisms can not efficiently attach to. The only part of the turbine that will not be in constant motion will be the base column and it will be subject to marine encrustation. The base column becoming encrusted with marine organisms will not produce any negative effects on the operation of the turbine. Remember, we’ve been in the subsea business for quite a long time, this is all proven technology.
Q: How does the aluminum alloy stand up to the corrosion factors in the salt environment. Anything in the ocean eventually gains critters or debris on it, how does your material choices hold up to 5-10 years down the line?
A: The majority of the components used in the production scale turbines will be non corrosive metals and high performance composite fiber. We are selecting proven materials that should provide for a minimum 25 year lifespan. However, It will last much longer with proper maintenance.
Q: What degree and frequency of maintenance do you foresee for these units?
A: Most of the systems on the turbines have been simplified to require as little maintenance as possible. Each blade module is composed of the blade, blade shaft, blade bearings, and blade bearing cups. Each blade module can be ejected and replaced by ROV. This system allows for almost all of the wear surfaces to easily be replaced in the field by robotics.
Q: What’s the lifespan on the turbine while in use in the ocean. How do they stand up to sea life and disasters like oil spills and hurricanes?
A: The turbines will be designed for a minimum 25 year lifespan. In regards to any outside variables, the turbines are installed at a depth that is completely unaffected by surface storms such as hurricanes and typhoons and surface debris like oil spills. Remember, these turbines are on the ocean floor, nowhere near the surface.
Q: How do you plan to combat the growth of barnacles and other adherents to the turbine? Traditional anti-fouling uses chemicals damaging to the environment and even then boat bottoms have to be scrubbed regularly
A: All the coatings we use are state of the art non toxic marine coatings. Objects moving at greater than 4 knots typically do not suffer from marine organism encrustation. Marine organisms need a low water velocity in which to effectively attach to an object with their biological cement. The only part of the turbine that will not be in constant motion will be the base column and it will be subject to marine encrustation. The base column becoming encrusted with marine organisms will not produce any negative effects on the operation of the turbine.
Q: How about seaweed? I have seen on the beaches and oceans of Florida and other states some pretty gnarly seaweed, long and strong that could easily wrap around your turbines and stop, maybe even damage them. Are they immune to this, or are you guys thinking of putting a fence around it to protect it against larger debris like that?
A: No worries, a megawatt scale turbine would not be stopped by seaweed. We are working with marine conservationist to select areas where there is very little marine life and flat sandy bottoms. Additionally, the high velocity zones where we collect the most energy are usually devoid of marine life.
Q: Have you done any long term testing in the ocean? If so was there any problems with bivalve, sea weed, algae, of similar stuff growing on the turbines?
A:We have been building , installing , and maintaining structures in ocean environments for over 40 years. We have a lot of experience with salt water compatible materials and cathodic protection.The production turbines will produce very little noise but they do have a very large surface area that most marine life will be able to detect from a great distance through echo location
Q: How will you deal with bio-fouling (filamentous algae getting trapped in vents, barnacle/mussel/drill worm/algae growth, etc.)? I know scientists who have been working with biofilms & preventing growth on ships but don’t know if that research is useful for your project.
A: In the past 10 years there have been great advancements in anti-biofouling non toxic mating coatings for materials susceptible to corrosion. One such coating is nano-carbon composite that creates a surface that marine organisms can not efficiently attach to.
Q: What kind of plans do you have about maintenance. In heavy currents I bet it’s hard to place the equipment there, but maintenance will be tricky too
A: We will be able to slow down and stop the turbine to do any maintenance. Additionally, the ROV’s can be tethered to the turbine during maintenance if needed.
Q: What process and mechanisms have you designed for recovery and recycling of failed or spent Ocean Energy Turbines? How would including the cost of “disposal” after use affect the cost of the Ocean Energy Turbine, in particular as compared with the as yet unincluded cost of environmental harm in fuel-generated power.
A: The Ocean Energy Turbine is modular in design so each component is replaceable as needed. The Ocean Energy Turbine is also composed mostly of metals and composite fiber, both of which are 100% recyclable. Currently we are currently working with a company in the development of 100% electric support / maintenance boats.
Q: Question about the basic design, as compared to other, axial-flow turbines: Are you worried about flotsam and small animals getting stuck between the louvers and preventing them from completely closing? Will the final version incorporate sensors to detect this?
A: This will not be a problem. The production turbines will have a very large gap ( 4 meters / 13 feet) between blades when the blades are open. Also, 99.9% of all sea life would be able to pass through the open blades unharmed. The turbine rotates at the same speed as the current so for a marine creature to get stuck between blades would require that creature to deliberately maintain a position between the ballads as they were closing. Additionally as the blades close they produce a positive pressure ahead of the blades which would push out ( self clean ) anything between the blades as they were closing.
Q: What are you doing to isolate your steel ball bearings from your aluminum frame? I can see that most of the parts are aluminum, but how will those not get gunked up in seawater. Is 6061 anodized the best choice for a corrosive environment?
A: All dissimilar metals are isolated with a dielectric coating. Aluminum was the best choice for prototyping the test turbine. Larger turbines will be mostly stainless and composite.
Q: Could these turbines be scaled to a size which could be attached to the hull of a ship below the waterline and reclaim part of the energy used to propel the ship?
A: It can not. This would create drag on the ship causing it to burn more fuel
Q: How much energy does a turbine produce per hour/day/month?
A: It Varies. For example an Ocean Energy Turbine with a 30 Meter blade span in 3 Meter per second flow will produce 13.5 Megawatts and power 13,500 average american homes.
Q: What size is the generator of the current model?
A: The first prototype is 52” in diameter. The production turbine will have 30 meter blades. There will be a number of different sizes of turbines for specific applications.
Q: What is the anticipated capacity factor?
A: the capacity factor will be very high because ocean currents produce a consistent flow 24 hours per day. The Turbine will operate at near full capacity all of the time.
Q: What size generator do you hope to build in the “production” type model?
A: Minimum of 13.5Megawatt / 30 Meter blade length
Q: What is your goal in terms of $/MWhr, and what is your plan to get it there?
A: 13.5Mw per hour per turbine
Q:How will you transfer the energy from the turbine to the shore then to homes?
A: Subsea power transmission cable manufactured by ABB to a shore base grid tie connection will transfer the power. Siemens and ABB have existing technology to safely transmit utility scale electricity underwater to shore. It is a product used in offshore wind farms. The shore grid tie system consists of grid tie inverters and output metering – all existing technology.
Q: How does your prototype compare to other ocean energy prototypes currently under development?
A: Our limited competition in the field of ocean energy has mostly tried to adapt existing wind turbine technology (propellers) to the marine environment. As water is 1000 times more dense than air, this has resulted in designs that are not optimized for collecting high density ocean energy, nor friendly to the marine environment. We decided to use our collective experience in the marine environment to design a turbine that was specifically optimized for collecting high density energy from ocean currents, while not damaging the marine environment. Our optimized high surface area design will allow us to collect up to thirty times the energy of propeller based designs in the same device footprint. This power density will make ocean renewable energy a financially feasible energy source.
Q: For the US, do you happen to know roughly how many quad BTU’s could potentially be generated yearly, given the square footage of US controlled ocean floor?
A: We do now know.
Q: Are you not better off trying to develop an ocean current technology based on lift instead of drag?
A: We have over the last ten years looked at other potential designs and from testing found this design to be the most efficient at converting ocean currents into usable electricity.
Q: How do you plan on fixing it to the ocean floor? Will buyers be able to fix (anchor) it to any type of ocean floor? Muck? Or only solid rocks?
A: This has actually been done before, and we will be using existing technology to mount the turbines. We will use pier, pad, or tension leg technology where needed similar to the mounting of an oil platform.
Q: If there is power loss along the transfer wires, will these be located primarily near coastal cities?
A: Most will be located along the coastlines and there is very little line loss. There has also been large innovations in the HVDC technology sector (High Voltage DC Cables)
Q: How can your turbine generate as much energy as 30 propeller type turbines on the same footprint?
A: Our turbine has up to 30 times the surface area of a propeller base turbine design
Q: Will the temperature of the water affect the power output or current flow?
A: Water temperature will have no effect on power output
Q: Why choose a 3 fin turbine?
A: 3 sets of blades was the most efficient design in our testing and calculations
Q: Have you conducted a lifecycle analysis?
A: This is one of the things we will do with the mid sized turbine once installed at FAU
Q: How will you distribute the energy to homes and places away from the coast?
A: We will use the national power grid
Q: Since there is a maximum fraction of kinetic energy that can be extracted from any flow, then if you try to extract more, the fluid has no energy left to go anywhere. Does this have any effect on the energy output?
A: Water at depth acts differently than water at the surface because water at the surface can displace the air above it (move around objects with more ease).
Q: What kind of numbers for power generation do you have from your test?
A: The results are up to 15kw per square meter at 3 meter per second flow. And there is very little speed reduction.
Q: How much does the turbine reduce the speed of the water behind it?
A: Very little. The turbine moves at almost the same speed as the flow
Q: When this becomes a large scale operation and there are say a hundred of these turbines in an area, would it be possible that it could affect the ocean current flow to an extent that might be concerning?
A: Not at all. You would run out of building materials on earth before you built enough turbines to have a negative impact on the oceans currents. Ocean currents are in part due to the gravitational pull between the earth ,the moon, the sun, and other planets. This makes it a truly renewable energy source.
Q: If these are implemented on a massive scale in just one area, what is the potential impact of the induced drag on the current in that region? If not introduced homogeneously, is there a possibility for current shift?
A:The turbines are not a static obstacle to a current they move with it. Additionally, you would not be able to build enough turbines to create a current shift.
Q: Where will your salt go from desalination? How will it impact the nearby marine ecology? What is your projected data on the fresh water project and it’s effect on the ocean(near and far)?
A: So we have two choices for this. Option 1: Because the turbine will be operating in high velocity current any brine produced by the Reverse Osmosis can be released downstream of the turbine through a diffuser system and will almost immediately be titrated into the water column without creating any pockets of abnormally high salinity. Option 2: The brine can be pumped to shore where it can be dehydrated and sold as a raw material.
Q: Have you considered fail safes for wildlife interruption? In the matter of a worst case scenario involving electric current relinquished into the ocean, what kind of consequences would result?
A: Salt water and the seafloor are inherently good paths to ground for any stray potentials. Stray potentials are typically not able to radiate in significant distance due to this fact. Ground fault interrupt power transmission systems will be used on the turbines.
Q: Would the funders of this project be able to benefit before other people with no link in supporting this project?
A: We are looking at the option of providing additional investment opportunities at a later stage of the project to the founding funders.