FAQ's & A's - Commercialization
When could we expect to have a prototype tested?
We’ve already had a successful sea trial of a prototype venturi tube. And we’re moving forward with the development of our first fully-functional (i.e. power-generating) prototype now. We hope to have it in the water by the end of May.
Aside from maintenance, What are some of the costs you would expect this technology to have?
We would expect to incur costs with respect to the following:
- to fabricate the devices;
- to deploy the devices;
- to set up the anchors and associated mooring buoys to hold the farm in place;
- to purchase and deploy a subsea power cable;
- to purchase and/or fabricate an onshore power substation; and,
- to purchase the land on which to place the subsea power station.However, the biggest cost that we would expect to incur for a deployment of a farm of our devices in the U.S. (at the moment at least) would be the cost of applying for and prosecuting applications at the state and national levels to deploy the farm and feed the resulting power into the grid. For this reason, we expect that our first deployments will be within international jurisdictions.
How do you plan to protect fish and whales from being injured?
We will be putting grates across each mouth to prevent all but the smallest of fish from being able to get inside.
However, the venturi tube is constantly reversing direction (reversing direction approximately every 4 seconds), and the speed of the water near each end of the venturi is moving relatively slowing. These two factors mean that fish shouldn't have any difficulty staying out of the venturi tube, or of getting out if they somehow manage to get inside.
In addition to this, the two mouths of each venturi tube will be at depths of about 50 feet and 150 feet, respectively. And, at the locations where we would expect to deploy these devices, we expect that most of the fish will either be near the surface, or near the bottom, and not at the depths where the venturi tube is operating.
We would also deploy our devices far from the migratory routes of any whales. However, as an added security measure, we will also either verify that our devices are readily detectable by marine mammals, or we will equip them with sonic warning devices in order to alert any nearby marine mammals to their location so that they can avoid them.
I am not fully convinced that your devices, of which large numbers will be required, will truly protect sea life. There are turtles, squids, and other animals that may swim near your devices..
The water moving in and out of the venturi tube mouths is only moving as fast as the waves are moving up and down, which isn't that fast. We will also have grates across the venturi mouths to help block access to any sea life.
The main thing is that since the tube is moving up and down, and since the water entering the mouths is moving rather slowly, and since the mouths will be covered by grates, it is quite unlikely that any fish, turtles or squids or other sea animals will get in to our devices.
We are committed to making sure that sea life is protected. We also realize that right now the CO2 in the air is acidifying the world’s oceans. That is the great danger facing many sea creatures today. If it's allowed continue, it could destroy the reefs of the world, and drive many species of sea animals to extinction.
We want to help save the oceans by replacing the burning of fossil fuels with non-polluting and renewable energy.
What are the best markets for this technology?
The ultimate market is supplying baseload power to coastal utilities with farms utilizing subsea power cables to get the power back to shore. These devices would also be useful to offshore oil rigs that currently get the electrical power that they need from diesel-powered generators.
It also seems likely that these devices would be a good complement to offshore wind farms. Typical offshore wind farms utilize, on average, less than 40% of the capacity of their subsea power cables. So, on those days when the wind isn't blowing at its maximum speed, Spindrift devices could supplement their power with power from the waves. Since, Spindrift devices are free-floating, they could be moored between wind turbines without adding any additional infrastructure.
In the long term, farms of these devices could be located far from shore and the power they generate could be used on site to generate chemical fuels, like methanol, from chemicals available in the air and seawater. This methanol (or other chemical intermediate) could be shipped to shore and used to power specially-equipped generation plants. The electrical power from these plants could then be added to the grid.
Have you projected maintenance costs?
We estimate that the annual operation and maintenance costs will be about $29k per device, or about $58 per kW.
If these farms are far out to sea, what are the risks and logistical concerns of maintaining miles of cables in rough seas?
A subsea power cable is expensive, at least $1M per mile, but it's also very robust and zero maintenance. Usually, the cable is buried about 6 to 10 feet beneath the sea floor. These kinds of cables have been in use for a long time. For instance, these types of cables are used to carry power from a mainland to an island.
Once they are laid down, they don't require any additional attention. The only event likely to damage such a cable is an undersea earthquake, if it causes a big shift or landslide. The other possibility is a really big ship dropping a really big anchor directly on to the cable. But these types of events are extremely rare.
How much will it cost to build each buoy?
We expect the fabrication of each 500-kW device to cost $100-$200k. Our capital costs were based on a figure of $170,000. (add section on manufacturing locally to create jobs)
What prompted you to think of this in the first place? (this question was directed to Brian)
I was involved in a project that required me to survey all existing alternative energy methods. I was rathered disheartened to see how limited the existing methods were with respect to one aspect or another. They couldn't scale. Or they were impractically complex or expensive. Or the displaced or damaged ecosystems. Or they just annoyed people (e.g. noise, sight, etc.). I also found quotes by both the EIA (i.e. the US Energy Information Administration) and the IEA (i.e. the International Energy Agency) that said that even though the amount of alternative energy coming on line was increasing, so was global demand for energy. And, both the EIA and the IEA didn't expect alternative energy to provide more than a few percent of the world's energy needs for decades to come.
Later, I set myself the task of figuring out what the characteristics of a "perfect" alternative energy system would be. One conclusion that I came to was that it would be able to operate on the surface of the deep sea. The energy density in the top 20 to 30 feet of the sea is huge. And, if an alternative energy device could operate not just tens, but even hundreds, of miles from land and extract this wave energy, then it could scale without limit, and provide enough power to satisfy the global energy appetite. This "deep-sea-capable" characteristic then had implications for other characteristics. Most notably, that the device couldn't be attached to the seafloor. When you can attach a line to the seafloor, it's relative easy to extract power from waves.
I thought that it would be useful if such a device would operate at the surface of the sea, instead of below, in order to make repairs and maintenance practical. And, I saw that other wave energy systems tended to be quite complex and expensive (e.g. Pelamis with its heaving steel segment and hydraulics systems). I saw that other wave energy systems that might be able to operate in the deep sea (perhaps "PowerBuoy", certainly "WaveBob") were also rather complex, and certainly quite expensive. And, seeing that cost and complexity were such barriers for other systems, I decided that it would be useful for my "perfect" device to be simple and inexpensive.
But, it turned out that designing a device that was simple, inexpensive, and could extract power from waves while free-floating was a definite challenge. Then, as I studied wave motion and learned that it was a surface phenomenon, and that wave motion dropped off exponentially with depth, I realized that exploiting this differential water motion might be a way to pull energy out of the waves. I started with the idea of a plain propeller suspended beneath a buoy, but that didn't generate enough power since the waves move up-and-down so slowly (and power is proportional to the cube of the water speed). (Also, it turns out that idea was patented many decades ago, and apparently never went anywhere.) Then I turned my attention to how to speed up the water around the turbine. And, when I came across a description of a venturi tube, that was it.
My analysis showed that using a venturi tube necessitated reducing the size of the turbine (which in general would lower power in direct proportion to the reduction in the turbine's cross-sectional area) but it also sped the water up. The increase in the water's speed was also in direct proportion to the reduction in the cross-sectional area of the tube's throat. But this increase the power in proportion to the cube of that increase. So, the reduction had one downside but a much bigger upside. And, because water can only be accelerated up to a certain point by a venturi tube, i.e. the "choke speed", an optimal venturi throat diameter is found with respect to the expected wave heights (and corresponding vertical water speeds).
Could you devices be used to desalinate seawater?
Desalinization of seawater is a great application for the Spindrift Energy devices. For this application we could locate a farm of Spindrift devices pretty far from shore and use the power locally (at sea) to desalinate seawater. The purified water could be put directly into a tanker stationed on site, or into large floating plastic sacks (NASA is actually doing something along these lines using algae). We could frequently bring the fresh water back to shore. This frees up the buoys to work without a subsea power cable, which is really nice.
Can your devices survive oil spills or would they have to be replaced?
Spindrift devices would survive an oil spill and continue operating normally. Oil in the water would have no detrimental effect on Spindrift devices at all.
How quickly are they replaced and working again when they do need replacement?
Our economic analyses, and the fact that Spindrift devices will be so inexpensive, suggest that it will be advantageous to populate each farm with more devices than will be needed to maximize the bandwidth of the farm's associated subsea power cable(s) most of the time. This will allow each farm to continue generating power at its maximum, i.e. at its "rated", level even when wave heights fall below the minimum optimal height.
Another consequence of this surplus capacity will be that when a Spindrift device will need to be replaced, the farm's output will likely remain at its maximum power level - essentially the "offline" device will simply reduce the farm's surplus capacity. We also expect to be able to replace a device in a single day.
Do they come with surfboards?
Regarding the free surfboards, it just so happens that everyone who purchases a farm of Spindrift devices (and pays for it in full) within the next 30 days will receive not ONE, but TWO, free surfboards. Cheers. :)
Does the cost of building the 'grid' or network which interconnects the Spindrift devices unduly offset the advantage of generating the power?
The cost of interconnecting the devices into a farm is rather simple and inexpensive. A farm will utilize 2 to 3 simple "concrete block" anchors to provide "anchor points" at the periphery of the network of devices. The devices themselves will be interconnected with simple mooring and power cables. The cables between each pair of devices will be kept in tension through the use of weights and floats on the cables. In this way, the devices will be free to move but as they separate the cabling will pull them back together. As they get too close the relatively stretched cables on neighboring buoys will pull them back apart. It will be simple, cheap and effective.
Does either the cost or leakage associated with back-hauling the power to shore present any problems?
If a subsea power cable is used to get the power from a farm of Spindrift devices back to shore, then there is a significant up-front cost of about $1M / mile of cable. However, these cables are very efficient. They only lose about 3% of their power for every 600 miles of cable used. That's a very acceptable loss. And, in later deployments, we can locate farms of devices far from shore and use the power right there in the ocean to generate chemical fuels, like methanol. We could then ship the methanol back to shore with tanker ships.
Can't this be combined in application with floating wind generators? High winds make high seas - a little synergy.
Yes! For example, Spindrift wave energy devices would be a very complimentary technology to offshore wind farms. We could provide supplemental power on the days when the wind isn't blowing its fastest. We could help an offshore wind farm to fill the unused bandwidth in their subsea power cable.
Studies have shown that offshore wind farms only generate about 40% of this maximum possible power (i.e. they only have a capacity factor of about 40%). Some studies have actually shown offshore wind farms in Europe generating substantially less than 40% of their maximum potential. That means that most offshore wind farms essentially waste about 60% of the capacity of their subsea power cables. We could fill that unused capacity with inexpensive power.
At a high level, how does this idea compare to other technologies being pursued to capture wave energy?
The TWO MOST SIGNIFICANT DIFFERENCES between Spindrift devices and the other devices being developed and deployed today are these:
DIFFERENCE ONE: Spindrift devices are ultra-simple, only 3 moving parts. This has several implications. First, they will be very low-cost, providing a very low capital cost per kW. Second, they will be very low-maintenance. The only expected maintenance will be adding a few drops of oil to the alternator bearings every year, and possibly replacing the turbine every 10 years (if cavitation is more of a problem than anticipated).
The efficiency of these devices, and their low-maintenance requirements, will help them to to deliver power at a cost far below that of coal-fired electrical power, currently the cheapest electrical power in wide-spread use.
DIFFERENCE TWO: Spindrift devices will be able to survive the worst storms at sea, even hurricanes. These devices, from the outside, are just concrete buoys bobbing up-and-down - much like navigational buoys. The shaft, and attached propeller, coming out of the bottom of each buoy will be well-protected. Spindrift devices will ride the waves of storms without damage.
LOW-COST, LOW-MAINTENANCE, DURABILITY
When you examine other devices carefully, you'll often see gears, joints, sliding parts with hard stops built in, etc. - all exposed to the seawater. And, when you look inside most other devices, you'll often see hydraulic lines, hydraulic rams, other hydraulic components, hand-made linear generators, neodymium magnets, etc. - very complex, very expensive, and very difficult to repair at sea. Spindrift devices will be lower-cost, lower-maintenance, and longer-lived than any of the other wave-energy devices we are currently aware of.
Furthermore, because Spindrift devices can operate in the deep sea, and not just onshore or near-shore like so many of the other systems being developed or deployed today, farms of Spindrift devices will not damage or displace sensitive coastal ecosystems, won't interfere with local shipping, and VERY IMPORTANTLY will be able to scale virtually without limit, providing as much power as is needed.
And, considering the ability of Spindrift devices to generate power in waves too small to energize many other devices, our analyses of historical wave data (obtained from NOAA buoys monitoring the wave climate for up to 20 years) show that farms of Spindrift devices would have capacity factors more than high enough to allow them to serve as baseload power sources (unlike wind, solar, and many other wave energy devices).
How you propose to maintain the Spindrift devices? How would the alternator be maintained/how often would it be accessed and how? What is your thinking about shaft and propeller longevity and maintenance?
There are primarily 5 aspects of the device that could potentially require maintenance. 1) The alternator 2) the shaft 3) the turbine 4) the outer hull of the buoy and/or venturi tube, and 5) the funnel-shaded interior hull of the venturi tube.
In case of insulation degradation of the cable over time, would the resulting partial discharge have any adverse impact on marine life?
Well, first of all, there shouldn’t be any significant degradation of the cables insulation over time – at least not for the cable’s lifetime of 50-60 years. This is helped by the fact that the vast majority of the cable will be buried. However, if there was a partial discharge due to some kind of degradation, then it would likely be quite a localized short between the two adjacent conductors in the cable. And, since the cable would be buried, this short would happen far beneath the sea floor. It is very unlikely that any sea life would be adversely affected.
You mention that your devices are very simple. How important is that, really?
For an ocean energy device operating in the deep sea, simplicity and reliability are critical for the economical operation of the devices, and for the generation of low-cost power. When a very large ocean energy device breaks down, or needs maintenance that can’t be handled by entering a hatch on the device, then, in most cases, the device would have to be towed to shore and repaired in dry dock. That’s time consuming and quite expensive. Imagine be faced with the need to repair a “Pelamis” device – 500 feet long and 700 tonnes. Towing it to shore, putting it in dry dock, repairing it, towing it back out to sea, and reconnecting it to the grid – would cost a lot of time, and a lot of money – raising the cost associated with the power it generates.
For ocean energy devices, the primary factor influencing the power-generation cost is the cost of maintenance and repair. So, if you want to create, deploy and operate a device that will generate truly cheap power, then it has to be very simple and very reliable – so that the frequency and difficulty of any needed maintenance and repairs will be minimized.
Spindrift devices were designed with simplicity and reliability in mind. That was the guiding criterion that led to its design. With only 3 moving parts, Spindrift devices should require very minimal maintenance and very minimal repairs (if any). And, because the bearings and electrical components are located high up in the buoy, and are accessible by one or more hatches on the side of the buoy, there should not be a need to tow a Spindrift device to shore for repairs.
Wave energy is an industry that has a great deal of potential, yet still has not been very successful in terms of reliance for baseload power requirements. What do you think of companies that are already on the market and what are some of the main differences between those ventures and Spindrift?
The current leaders in wave energy are:
“Ocean Power Technologies” (“OPT”) makers of the “PowerBuoy”, “WaveBob LLC” makers of the “WaveBob”, and “Pelamis”
Each Pelamis device is a 150-meter-long structure made of 3-meter-diameter tubular segments that are joined together by hinges. This device floats on the surface (like a giant snake) and is moored in relatively shallow water so as to point into the waves approaching a coastline. As the waves roll under the device, the tubular segments flex about their hinges, and hydraulic rams transfer power to a hydraulic power system between each pair of tubes.
These devices are expected to generate a maximum of 750 kW of power, and an average of about 150 kW. They are very large, very complicated and very expensive. And, they tend to break in storms.
The “Ocean Power Technologies” (i.e. “OPT”) appears to be the leader at the moment. Of all the products, I regard their “PowerBuoy” as one of the two best competitive products (the other being “WaveBob”).
Three hydrokinetic energy providers, “WaveBob”, “Ocean Power Technologies”, and “Pelamis Wave Power”, have made headway into this space and are potential competitors. However, all of these technologies are considerably more complex and many times more costly than SE devices.
Instead of multiple large components held together by sliding and/or articulating joints, the Spindrift device is a single, integrated and static hull, comprising a buoy section and a venturi tube section. Instead of complicated power takeoff schemes involving linear generators, hydraulics, etc., the Spindrift device has 3 moving parts: a turbine, a shaft and an alternator. Instead of implementing complicated strategies to avoid damage from excessive storm-related waves, Spindrift devices are basically fortified buoys that just ride out inclement weather.
Where the complexity of the competing devices results in high costs of fabrication, maintenance and power-generation, the simplicity of the Spindrift device is expected to result in low capital costs and low maintenance and power-generation costs.
Who do you think are the main benefactors to a successful launch and worldwide deployment of Spindrift Energy devices?
Initially, the main benefactors will be oil companies and coastal utilities. The oil companies will have a new source of electrical power with which to energize their offshore oil rigs. This will allow them to end, or greatly reduce, the use of the diesel-powered generators that are currently providing the 3-10 MW of electrical power that they require. This will mean the end of their need to transport and store large amounts of diesel on the oil rigs. It will save them a great deal of money. It will also greatly improve the safety of the rigs by ending the need to store hundreds of gallons of flammable liquids on the rigs.
The coastal utilities will benefit by having an abundant alternate source of renewable electrical power with which to satisfy their renewable energy mandates (and/or renewable portfolio standards).
In the long term, our devices will supply a greater and greater percentage of the world’s electrical power. This will greatly reduce the rate at which greenhouse gases are generated, and that should reduce the rate of global warming and ocean acidification. And, over time, the price that we charge for the electrical power that our devices generate will come down to the point that it approaches the cost of generation, i.e. about 2 cents per kWh. This will enable coastal utilities to reduce the rates that they charge their customers for electrical power.
Stay Tuned:
What types of advisors and investors do you believe would be a good fit with your team?
What causes will Spindrift support once profitable?
Once a prototype is tested, how long before you will launch a pilot program?
Once your pilot program is in place, how do you intend to sell and distribute your devices?
Who will be responsible for maintenance of the devices?
What will a Spindrift “farm” look like? How much power can it produce, and how does that compare to the upfront cost of other energy sources?
(insert chart showing power generation assuming certain wave heights and size devices)
I represent the Department of Energy of a certain state or nation and am seeking to diversify my energy portfolio with renewable sources. What is the process of utilizing Spindrift devices to support our grid requirements?
How much time and investment would be required and what would the payback be?
Once deployed, how will Spindrift work with me to ensure our energy requirements are met?
What is a realistic expectation of the percentage of baseload power I can depend on and how might that change over the years?
What have been some of the main concerns about this venture that you have heard, and how have you responded?
If you had $500k of investment, what would you do with it, and how far would it take this company? What about $2 million?
What are the environmental implications of launching Spindrift devices in the sea?
What sea conditions are ideal for deployment of the devices (depth, distance from shore, latitude)?
Where will the devices be manufactured?
What partnerships will be mutually beneficial?
Once version 1 devices are deployed, how do you intend to deliver updates to commercial users?
What are the key assumptions that make this team think they can build an offshore power plant that will generate energy for a couple of pennies per kWh? Have they been validated? What are they based on?
What do you think have been the biggest reservations from investors and buyers that you've spoken with?
What do you think has stopped them from saying - "OK, lets try thisout on a small scale now, here's X $, when can you deliver?"
Where do you see Spindrift in a year? Five years?
What do you personally hope to achieve from launching Spindrift?
What types of commercial energy users have you spoken with to date?
Who do you anticipate your first customers will be?
What are some of the primary challenges you face in launching Spindrift?
Where are you looking to deploy the pilot programs and why?
When could we expect to have a prototype tested?
We’ve already had a successful sea trial of a prototype venturi tube. And we’re moving forward with the development of our first fully-functional (i.e. power-generating) prototype now. We hope to have it in the water by the end of May.
Aside from maintenance, What are some of the costs you would expect this technology to have?
We would expect to incur costs with respect to the following:
- to fabricate the devices;
- to deploy the devices;
- to set up the anchors and associated mooring buoys to hold the farm in place;
- to purchase and deploy a subsea power cable;
- to purchase and/or fabricate an onshore power substation; and,
- to purchase the land on which to place the subsea power station.However, the biggest cost that we would expect to incur for a deployment of a farm of our devices in the U.S. (at the moment at least) would be the cost of applying for and prosecuting applications at the state and national levels to deploy the farm and feed the resulting power into the grid. For this reason, we expect that our first deployments will be within international jurisdictions.
How do you plan to protect fish and whales from being injured?
We will be putting grates across each mouth to prevent all but the smallest of fish from being able to get inside.
However, the venturi tube is constantly reversing direction (reversing direction approximately every 4 seconds), and the speed of the water near each end of the venturi is moving relatively slowing. These two factors mean that fish shouldn't have any difficulty staying out of the venturi tube, or of getting out if they somehow manage to get inside.
In addition to this, the two mouths of each venturi tube will be at depths of about 50 feet and 150 feet, respectively. And, at the locations where we would expect to deploy these devices, we expect that most of the fish will either be near the surface, or near the bottom, and not at the depths where the venturi tube is operating.
We would also deploy our devices far from the migratory routes of any whales. However, as an added security measure, we will also either verify that our devices are readily detectable by marine mammals, or we will equip them with sonic warning devices in order to alert any nearby marine mammals to their location so that they can avoid them.
I am not fully convinced that your devices, of which large numbers will be required, will truly protect sea life. There are turtles, squids, and other animals that may swim near your devices..
The water moving in and out of the venturi tube mouths is only moving as fast as the waves are moving up and down, which isn't that fast. We will also have grates across the venturi mouths to help block access to any sea life.
The main thing is that since the tube is moving up and down, and since the water entering the mouths is moving rather slowly, and since the mouths will be covered by grates, it is quite unlikely that any fish, turtles or squids or other sea animals will get in to our devices.
We are committed to making sure that sea life is protected. We also realize that right now the CO2 in the air is acidifying the world’s oceans. That is the great danger facing many sea creatures today. If it's allowed continue, it could destroy the reefs of the world, and drive many species of sea animals to extinction.
We want to help save the oceans by replacing the burning of fossil fuels with non-polluting and renewable energy.
What are the best markets for this technology?
The ultimate market is supplying baseload power to coastal utilities with farms utilizing subsea power cables to get the power back to shore. These devices would also be useful to offshore oil rigs that currently get the electrical power that they need from diesel-powered generators.
It also seems likely that these devices would be a good complement to offshore wind farms. Typical offshore wind farms utilize, on average, less than 40% of the capacity of their subsea power cables. So, on those days when the wind isn't blowing at its maximum speed, Spindrift devices could supplement their power with power from the waves. Since, Spindrift devices are free-floating, they could be moored between wind turbines without adding any additional infrastructure.
In the long term, farms of these devices could be located far from shore and the power they generate could be used on site to generate chemical fuels, like methanol, from chemicals available in the air and seawater. This methanol (or other chemical intermediate) could be shipped to shore and used to power specially-equipped generation plants. The electrical power from these plants could then be added to the grid.
Have you projected maintenance costs?
We estimate that the annual operation and maintenance costs will be about $29k per device, or about $58 per kW.
If these farms are far out to sea, what are the risks and logistical concerns of maintaining miles of cables in rough seas?
A subsea power cable is expensive, at least $1M per mile, but it's also very robust and zero maintenance. Usually, the cable is buried about 6 to 10 feet beneath the sea floor. These kinds of cables have been in use for a long time. For instance, these types of cables are used to carry power from a mainland to an island.
Once they are laid down, they don't require any additional attention. The only event likely to damage such a cable is an undersea earthquake, if it causes a big shift or landslide. The other possibility is a really big ship dropping a really big anchor directly on to the cable. But these types of events are extremely rare.
How much will it cost to build each buoy?
We expect the fabrication of each 500-kW device to cost $100-$200k. Our capital costs were based on a figure of $170,000. (add section on manufacturing locally to create jobs)
What prompted you to think of this in the first place? (this question was directed to Brian)
I was involved in a project that required me to survey all existing alternative energy methods. I was rathered disheartened to see how limited the existing methods were with respect to one aspect or another. They couldn't scale. Or they were impractically complex or expensive. Or the displaced or damaged ecosystems. Or they just annoyed people (e.g. noise, sight, etc.). I also found quotes by both the EIA (i.e. the US Energy Information Administration) and the IEA (i.e. the International Energy Agency) that said that even though the amount of alternative energy coming on line was increasing, so was global demand for energy. And, both the EIA and the IEA didn't expect alternative energy to provide more than a few percent of the world's energy needs for decades to come.
Later, I set myself the task of figuring out what the characteristics of a "perfect" alternative energy system would be. One conclusion that I came to was that it would be able to operate on the surface of the deep sea. The energy density in the top 20 to 30 feet of the sea is huge. And, if an alternative energy device could operate not just tens, but even hundreds, of miles from land and extract this wave energy, then it could scale without limit, and provide enough power to satisfy the global energy appetite. This "deep-sea-capable" characteristic then had implications for other characteristics. Most notably, that the device couldn't be attached to the seafloor. When you can attach a line to the seafloor, it's relative easy to extract power from waves.
I thought that it would be useful if such a device would operate at the surface of the sea, instead of below, in order to make repairs and maintenance practical. And, I saw that other wave energy systems tended to be quite complex and expensive (e.g. Pelamis with its heaving steel segment and hydraulics systems). I saw that other wave energy systems that might be able to operate in the deep sea (perhaps "PowerBuoy", certainly "WaveBob") were also rather complex, and certainly quite expensive. And, seeing that cost and complexity were such barriers for other systems, I decided that it would be useful for my "perfect" device to be simple and inexpensive.
But, it turned out that designing a device that was simple, inexpensive, and could extract power from waves while free-floating was a definite challenge. Then, as I studied wave motion and learned that it was a surface phenomenon, and that wave motion dropped off exponentially with depth, I realized that exploiting this differential water motion might be a way to pull energy out of the waves. I started with the idea of a plain propeller suspended beneath a buoy, but that didn't generate enough power since the waves move up-and-down so slowly (and power is proportional to the cube of the water speed). (Also, it turns out that idea was patented many decades ago, and apparently never went anywhere.) Then I turned my attention to how to speed up the water around the turbine. And, when I came across a description of a venturi tube, that was it.
My analysis showed that using a venturi tube necessitated reducing the size of the turbine (which in general would lower power in direct proportion to the reduction in the turbine's cross-sectional area) but it also sped the water up. The increase in the water's speed was also in direct proportion to the reduction in the cross-sectional area of the tube's throat. But this increase the power in proportion to the cube of that increase. So, the reduction had one downside but a much bigger upside. And, because water can only be accelerated up to a certain point by a venturi tube, i.e. the "choke speed", an optimal venturi throat diameter is found with respect to the expected wave heights (and corresponding vertical water speeds).
Could you devices be used to desalinate seawater?
Desalinization of seawater is a great application for the Spindrift Energy devices. For this application we could locate a farm of Spindrift devices pretty far from shore and use the power locally (at sea) to desalinate seawater. The purified water could be put directly into a tanker stationed on site, or into large floating plastic sacks (NASA is actually doing something along these lines using algae). We could frequently bring the fresh water back to shore. This frees up the buoys to work without a subsea power cable, which is really nice.
Can your devices survive oil spills or would they have to be replaced?
Spindrift devices would survive an oil spill and continue operating normally. Oil in the water would have no detrimental effect on Spindrift devices at all.
How quickly are they replaced and working again when they do need replacement?
Our economic analyses, and the fact that Spindrift devices will be so inexpensive, suggest that it will be advantageous to populate each farm with more devices than will be needed to maximize the bandwidth of the farm's associated subsea power cable(s) most of the time. This will allow each farm to continue generating power at its maximum, i.e. at its "rated", level even when wave heights fall below the minimum optimal height.
Another consequence of this surplus capacity will be that when a Spindrift device will need to be replaced, the farm's output will likely remain at its maximum power level - essentially the "offline" device will simply reduce the farm's surplus capacity. We also expect to be able to replace a device in a single day.
Do they come with surfboards?
Regarding the free surfboards, it just so happens that everyone who purchases a farm of Spindrift devices (and pays for it in full) within the next 30 days will receive not ONE, but TWO, free surfboards. Cheers. :)
Does the cost of building the 'grid' or network which interconnects the Spindrift devices unduly offset the advantage of generating the power?
The cost of interconnecting the devices into a farm is rather simple and inexpensive. A farm will utilize 2 to 3 simple "concrete block" anchors to provide "anchor points" at the periphery of the network of devices. The devices themselves will be interconnected with simple mooring and power cables. The cables between each pair of devices will be kept in tension through the use of weights and floats on the cables. In this way, the devices will be free to move but as they separate the cabling will pull them back together. As they get too close the relatively stretched cables on neighboring buoys will pull them back apart. It will be simple, cheap and effective.
Does either the cost or leakage associated with back-hauling the power to shore present any problems?
If a subsea power cable is used to get the power from a farm of Spindrift devices back to shore, then there is a significant up-front cost of about $1M / mile of cable. However, these cables are very efficient. They only lose about 3% of their power for every 600 miles of cable used. That's a very acceptable loss. And, in later deployments, we can locate farms of devices far from shore and use the power right there in the ocean to generate chemical fuels, like methanol. We could then ship the methanol back to shore with tanker ships.
Can't this be combined in application with floating wind generators? High winds make high seas - a little synergy.
Yes! For example, Spindrift wave energy devices would be a very complimentary technology to offshore wind farms. We could provide supplemental power on the days when the wind isn't blowing its fastest. We could help an offshore wind farm to fill the unused bandwidth in their subsea power cable.
Studies have shown that offshore wind farms only generate about 40% of this maximum possible power (i.e. they only have a capacity factor of about 40%). Some studies have actually shown offshore wind farms in Europe generating substantially less than 40% of their maximum potential. That means that most offshore wind farms essentially waste about 60% of the capacity of their subsea power cables. We could fill that unused capacity with inexpensive power.
At a high level, how does this idea compare to other technologies being pursued to capture wave energy?
The TWO MOST SIGNIFICANT DIFFERENCES between Spindrift devices and the other devices being developed and deployed today are these:
DIFFERENCE ONE: Spindrift devices are ultra-simple, only 3 moving parts. This has several implications. First, they will be very low-cost, providing a very low capital cost per kW. Second, they will be very low-maintenance. The only expected maintenance will be adding a few drops of oil to the alternator bearings every year, and possibly replacing the turbine every 10 years (if cavitation is more of a problem than anticipated).
The efficiency of these devices, and their low-maintenance requirements, will help them to to deliver power at a cost far below that of coal-fired electrical power, currently the cheapest electrical power in wide-spread use.
DIFFERENCE TWO: Spindrift devices will be able to survive the worst storms at sea, even hurricanes. These devices, from the outside, are just concrete buoys bobbing up-and-down - much like navigational buoys. The shaft, and attached propeller, coming out of the bottom of each buoy will be well-protected. Spindrift devices will ride the waves of storms without damage.
LOW-COST, LOW-MAINTENANCE, DURABILITY
When you examine other devices carefully, you'll often see gears, joints, sliding parts with hard stops built in, etc. - all exposed to the seawater. And, when you look inside most other devices, you'll often see hydraulic lines, hydraulic rams, other hydraulic components, hand-made linear generators, neodymium magnets, etc. - very complex, very expensive, and very difficult to repair at sea. Spindrift devices will be lower-cost, lower-maintenance, and longer-lived than any of the other wave-energy devices we are currently aware of.
Furthermore, because Spindrift devices can operate in the deep sea, and not just onshore or near-shore like so many of the other systems being developed or deployed today, farms of Spindrift devices will not damage or displace sensitive coastal ecosystems, won't interfere with local shipping, and VERY IMPORTANTLY will be able to scale virtually without limit, providing as much power as is needed.
And, considering the ability of Spindrift devices to generate power in waves too small to energize many other devices, our analyses of historical wave data (obtained from NOAA buoys monitoring the wave climate for up to 20 years) show that farms of Spindrift devices would have capacity factors more than high enough to allow them to serve as baseload power sources (unlike wind, solar, and many other wave energy devices).
How you propose to maintain the Spindrift devices? How would the alternator be maintained/how often would it be accessed and how? What is your thinking about shaft and propeller longevity and maintenance?
There are primarily 5 aspects of the device that could potentially require maintenance. 1) The alternator 2) the shaft 3) the turbine 4) the outer hull of the buoy and/or venturi tube, and 5) the funnel-shaded interior hull of the venturi tube.
- The alternator should only require the addition of a little bit of oil to its bearings once a year. Generators have been observed to operate on oscillating water columns for years without maintenance, and they are exposed to almost an identical pattern of speeding up and slowing down as would characterize the operation of the alternator in a Spindrift device. Therefore, we expect the alternators to operate with only the very minimal amount of maintenance mentioned. Access to the alternator, and the other components located in the upper portion of each buoy, would be accessible by one or more hatches on the sides of the buoy.
- Corrosion on the shaft will be prevented through the application of an “impressed current”. And, the shaft is not expected to require any maintenance at all during the lifetime of a Spindrift device.
- If cavitation proves to be more of a problem than currently anticipated, then it may be necessary to replace the blades on the turbine every 10 years (i.e. once during the lifetime of a Spindrift device). No other maintenance should be needed. And, the turbine (i.e. the propeller) should otherwise last for the lifetime of the device.
- We won’t try to prevent sea life from adhering to the outer hulls of the buoy and venturi tube. In essence, the hulls of the buoys will create artificial reefs that will encourage the development of communities of fish and other sea life in the vicinity of our devices. Such growth isn’t expected to have any detrimental effect on the performance of the Spindrift devices.
- And, finally, the inner funnel-shaped hull of the venturi tube. We expect the rapid, and constantly reversing, flow of seawater through the venturi tube to prevent biofouling on the surfaces of the critical portions of the venturi tube and turbine. And, because of the depth of the venturi tube, and the depth of the water in which the Spindrift devices will operate, it is less likely that there will be enough light and/or nutrients available to support much biofouling of the inner or outer surfaces of the venturi tube. However, it is possible that we may need to take steps to inhibit biofouling along the portions of the venturi tube closest to the mouths. (Near the mouths, the water reverses, but it flows more slowly.) We are considering many options available to us to accomplish that.
In case of insulation degradation of the cable over time, would the resulting partial discharge have any adverse impact on marine life?
Well, first of all, there shouldn’t be any significant degradation of the cables insulation over time – at least not for the cable’s lifetime of 50-60 years. This is helped by the fact that the vast majority of the cable will be buried. However, if there was a partial discharge due to some kind of degradation, then it would likely be quite a localized short between the two adjacent conductors in the cable. And, since the cable would be buried, this short would happen far beneath the sea floor. It is very unlikely that any sea life would be adversely affected.
You mention that your devices are very simple. How important is that, really?
For an ocean energy device operating in the deep sea, simplicity and reliability are critical for the economical operation of the devices, and for the generation of low-cost power. When a very large ocean energy device breaks down, or needs maintenance that can’t be handled by entering a hatch on the device, then, in most cases, the device would have to be towed to shore and repaired in dry dock. That’s time consuming and quite expensive. Imagine be faced with the need to repair a “Pelamis” device – 500 feet long and 700 tonnes. Towing it to shore, putting it in dry dock, repairing it, towing it back out to sea, and reconnecting it to the grid – would cost a lot of time, and a lot of money – raising the cost associated with the power it generates.
For ocean energy devices, the primary factor influencing the power-generation cost is the cost of maintenance and repair. So, if you want to create, deploy and operate a device that will generate truly cheap power, then it has to be very simple and very reliable – so that the frequency and difficulty of any needed maintenance and repairs will be minimized.
Spindrift devices were designed with simplicity and reliability in mind. That was the guiding criterion that led to its design. With only 3 moving parts, Spindrift devices should require very minimal maintenance and very minimal repairs (if any). And, because the bearings and electrical components are located high up in the buoy, and are accessible by one or more hatches on the side of the buoy, there should not be a need to tow a Spindrift device to shore for repairs.
Wave energy is an industry that has a great deal of potential, yet still has not been very successful in terms of reliance for baseload power requirements. What do you think of companies that are already on the market and what are some of the main differences between those ventures and Spindrift?
The current leaders in wave energy are:
“Ocean Power Technologies” (“OPT”) makers of the “PowerBuoy”, “WaveBob LLC” makers of the “WaveBob”, and “Pelamis”
Each Pelamis device is a 150-meter-long structure made of 3-meter-diameter tubular segments that are joined together by hinges. This device floats on the surface (like a giant snake) and is moored in relatively shallow water so as to point into the waves approaching a coastline. As the waves roll under the device, the tubular segments flex about their hinges, and hydraulic rams transfer power to a hydraulic power system between each pair of tubes.
These devices are expected to generate a maximum of 750 kW of power, and an average of about 150 kW. They are very large, very complicated and very expensive. And, they tend to break in storms.
The “Ocean Power Technologies” (i.e. “OPT”) appears to be the leader at the moment. Of all the products, I regard their “PowerBuoy” as one of the two best competitive products (the other being “WaveBob”).
Three hydrokinetic energy providers, “WaveBob”, “Ocean Power Technologies”, and “Pelamis Wave Power”, have made headway into this space and are potential competitors. However, all of these technologies are considerably more complex and many times more costly than SE devices.
Instead of multiple large components held together by sliding and/or articulating joints, the Spindrift device is a single, integrated and static hull, comprising a buoy section and a venturi tube section. Instead of complicated power takeoff schemes involving linear generators, hydraulics, etc., the Spindrift device has 3 moving parts: a turbine, a shaft and an alternator. Instead of implementing complicated strategies to avoid damage from excessive storm-related waves, Spindrift devices are basically fortified buoys that just ride out inclement weather.
Where the complexity of the competing devices results in high costs of fabrication, maintenance and power-generation, the simplicity of the Spindrift device is expected to result in low capital costs and low maintenance and power-generation costs.
Who do you think are the main benefactors to a successful launch and worldwide deployment of Spindrift Energy devices?
Initially, the main benefactors will be oil companies and coastal utilities. The oil companies will have a new source of electrical power with which to energize their offshore oil rigs. This will allow them to end, or greatly reduce, the use of the diesel-powered generators that are currently providing the 3-10 MW of electrical power that they require. This will mean the end of their need to transport and store large amounts of diesel on the oil rigs. It will save them a great deal of money. It will also greatly improve the safety of the rigs by ending the need to store hundreds of gallons of flammable liquids on the rigs.
The coastal utilities will benefit by having an abundant alternate source of renewable electrical power with which to satisfy their renewable energy mandates (and/or renewable portfolio standards).
In the long term, our devices will supply a greater and greater percentage of the world’s electrical power. This will greatly reduce the rate at which greenhouse gases are generated, and that should reduce the rate of global warming and ocean acidification. And, over time, the price that we charge for the electrical power that our devices generate will come down to the point that it approaches the cost of generation, i.e. about 2 cents per kWh. This will enable coastal utilities to reduce the rates that they charge their customers for electrical power.
Stay Tuned:
What types of advisors and investors do you believe would be a good fit with your team?
What causes will Spindrift support once profitable?
Once a prototype is tested, how long before you will launch a pilot program?
Once your pilot program is in place, how do you intend to sell and distribute your devices?
Who will be responsible for maintenance of the devices?
What will a Spindrift “farm” look like? How much power can it produce, and how does that compare to the upfront cost of other energy sources?
(insert chart showing power generation assuming certain wave heights and size devices)
I represent the Department of Energy of a certain state or nation and am seeking to diversify my energy portfolio with renewable sources. What is the process of utilizing Spindrift devices to support our grid requirements?
How much time and investment would be required and what would the payback be?
Once deployed, how will Spindrift work with me to ensure our energy requirements are met?
What is a realistic expectation of the percentage of baseload power I can depend on and how might that change over the years?
What have been some of the main concerns about this venture that you have heard, and how have you responded?
If you had $500k of investment, what would you do with it, and how far would it take this company? What about $2 million?
What are the environmental implications of launching Spindrift devices in the sea?
What sea conditions are ideal for deployment of the devices (depth, distance from shore, latitude)?
Where will the devices be manufactured?
What partnerships will be mutually beneficial?
Once version 1 devices are deployed, how do you intend to deliver updates to commercial users?
What are the key assumptions that make this team think they can build an offshore power plant that will generate energy for a couple of pennies per kWh? Have they been validated? What are they based on?
What do you think have been the biggest reservations from investors and buyers that you've spoken with?
What do you think has stopped them from saying - "OK, lets try thisout on a small scale now, here's X $, when can you deliver?"
Where do you see Spindrift in a year? Five years?
What do you personally hope to achieve from launching Spindrift?
What types of commercial energy users have you spoken with to date?
Who do you anticipate your first customers will be?
What are some of the primary challenges you face in launching Spindrift?
Where are you looking to deploy the pilot programs and why?
Spindrift Energy Copyright 2012
