The above animation is a simplified visual representation of river-installed hydrokinetic Shuttle Foil system.
The Shuttle Foil Approach to Kinetic Energy Conversion
It is widely believed that history’s most prolific inventor and artist, Leonardo Da Vinci designed and used the first ‘Reaction ferry’ to cross a river in his home town. Instead of paddling across the river, he realized by tethering the front of his boat to a long rope and tying the other end of the rope well upstream, he could use his paddle like a rudder to create an angle of attack between the hull and the flow, hence, use the (kinetic) energy in the flow, to ‘push’ his boat across the flow without the need to paddle; the kinetic energy in flow did the necessary ‘work’ for him.
Today, 500 years later, much larger Reaction ferries continue to operate in the identical fashion, using only slightly different executions, however, they still don’t have motors; they still rely solely on the kinetic energy contained in flowing water as their sole means of propulsion.
Modern Reaction ferries have much higher displacement weights, some as high as 65 tons, what is so exciting about the approach is that even at 600,000 tons displacement weigh, Reaction ferries would still only use the kinetic energy contained in the flow, why; because the physics involved dictate it!
The Physics Involved:
As one might guess, the ‘force’ needed to move a 65 ton Reaction ferry example is considerable. In the case of a large Reaction ferry, whose sole purpose is to provide transportation of vehicles and people across a river, the ‘all up’ displacement is made up of both the empty vessel and cargo. However, in a ‘generation application’ the vast majority of the vessel weight is not present as the ‘vessel’s’ function is to only provide ‘flotation’ to the underwater hydrofoils which are used to redirect the flowing water. So what can be had in the case of a ‘floating foil array’ (FFA) Shuttle foil system, is the tractive power of a much larger Reaction ferry than the 65 ton example mentioned, without the actual displacement weight. So when such a FFA Shuttle foil is in operation, it can take a much higher percentage of the converted kinetic energy and use it to ‘pull’ on an attached set of cable loops which are attached to either shoreline generators. The pulling action on the cable loops turns the shoreline mounted generators, or air compressors or water pumps to either make single step electricity or temporary energy storage for later release.
Bigger is Better:
It is important to understand that there is NO technical reason as to why the core FFA Reaction ferry approach cannot be built to extreme size for use in tidal flows or even ocean currents, with of course, the equivalent high outputs of into the 10s, even hundreds of megawatts per system.
It is important to point out that Shuttle foil systems do not have limiting factors such as ‘lever arm loading’ issues inherent to conventional rotary kinetic energy harvesting systems. Nor do they have to function at high velocities in order to make contact with more of the passing kinetic energy. The use of large area sails/foils/wings inherently makes equal contact over the entire surface area with the passing kinetic energy – unlike conventional rotating propeller harvesting systems.
Their slow moving nature, even for extremely large Shuttle Foil systems, will NOT pose hazards to marine life or people.
Estimated Installation and Direct Operating Costs of Shuttle Foil Generation Systems:
Based on the long known DOC of Reaction ferries worldwide, we believe it will be possible to achieve a cost per kWh of only (USD) 1/2 cent.
This cost estimate is based on the use of ordinary wire rope cables and (proven) off-the-shelf generators. All system controls / components are also situation above the waterline on-shore. Such an installation format makes routine servicing simple and (very) low cost. All major maintenance, such as generator replacement or cable loop replacement, can also be easily carried out; there is no need for specialized equipment, divers, etc., or system shut down for days 0r even many hours. Given the use of such simple retention and generation equipment, the cost per installed kW will be considerably lower than the next closest generation means. Depending on what materials are used, the floating foil array itself will require very little maintenance over decades of service.
To support our claims: One locally operating steel hull Reaction ferry has a rough DOC of 2 cents per hour. This cost is calculated based on daily hours of operation and cost of replacing the main retention cable once every three to four years (at a cost of $1700). There is no other DOC for this particular Reaction ferry and this particular Reaction ferry operates daylight hours for 365 days a year. In that time it does 30,000 ‘shuttles’ and carries 100,000 passengers (and their vehicles). It has been doing that for over 40 years now. There has been a Reaction ferry in the same location for over 125 years.
So far, not one PhD engineer (which has taken the time to familiarize themselves with our Shuttle Foil generation approach) has been able to find even minor flaws with the process; not one. Everything considered, especially the fact that these little workhorses have been reliably operating around the world for five centuries, the Shuttle Foil approach could prove to be the clean energy miracle the world needs today.
With additional R&D / process refinement, all TW/SF variants will become higher output, more robust, lower cost. SF can also be designed to be highly viable for use in tidal flows and ocean currents, and this, within only a few years (not decades) of commencing the needed process optimization engineering.
How the SF process works:
The Earth’s kinetic energy is both abundant and endless. In fact our planet has so much kinetic energy that it can provide all of humanity’s total energy needs – forever! It’s just a matter of creating the appropriate harvesting infrastructure.
To the average person, wind is just moving air, and tides and rivers are just flowing water but to someone who understands the awesome power contained within these seemingly innocuous flows, they are tremendous and endless sources of clean, cheap energy.
Kinetic energy contained in wind/flowing water can be measured in ‘watts per square or cubic meter’. In slow moving wind, there simply isn’t much energy present to be harvested by conventional harvesting means, however, Shuttle Foil system can place very large sails/foils/wings into the flow, as a result, SF systems are able to make contact with far more of the passing kinetic energy. So even in low flow conditions Shuttle Foil systems will be able to harvest meaningful amounts of energy.
When placed into flowing water, Shuttle Foil systems can harvest from vastly greater ‘swept areas’ than any other ‘open flow turbine’ system in use today. Water depth is also not a factor for Shuttle foil systems, as they can be ‘floating’ or ‘semi-floating’ i.e. reach deep down into ocean currents.
All open turbines, such as the ones used in rivers or shallow tidal flows, have one thing in common, they operate from a fixed position, meaning they can only harvest from the ‘stream tube’ directly in front of them. Their harvest ability/output is further restricted by their overall diameter which is typically no more that several meters.
Then there are the issues of operating electrical generation equipment underwater; putting electrical generation equipment underwater means specialized maintenance procedures and personnel.
Hydrokinetic Shuttle Foil systems will not have these inherent issues as only the ‘kinetic energy capture/harvesting’ portion of system operates underwater, the mechanical energy conversion process (to electricity or other forms of usable energies), is carried out above the waterline, on shore or on barges, by way of the ‘cable loop’ suspension systems used by all Shuttle Foil systems.
Why Hydrokinetic Harvesting is Better than Wind:
A cubic meter of water weighs 1,000 kg (2,200lbs) making it over 800 times heavier than a cubic meter of air (approx 1.2 kilograms or 2.6 lbs). So when rivers, tides and ocean currents flow, they contain vastly more kinetic energy per cubic unit of moving flow (at equivalent velocity) than wind.
In large scale hydrokinetic applications, such as for harvesting from tidal flows or in high volume flow rivers (such as the Amazon River), SF systems will be able place many hundreds (perhaps even thousands) of square meters of hydrofoil area into the flow (not necessarily using ‘underwater sails’), this will result in being able to harvest high amounts/percentages of the passing kinetic energy.
For wind installations: TW/SF systems will work in the same fashion as sailboats work. Being attached to ‘movable cable loops’, TW/SF sails will pull on the cable loops in one direction and then, by reversing the ‘angle of attack’ relative to the airflow (just like a sailboat tacking) they are moved in the opposite direction.
TW/SF system cable loops are secured to two mounting-points, for wind, on a hillside/hill top, for hydrokinetic installation, on each shore (or on barges).
System cable loops are wrap around ‘end-of-system-travel-wheels’ called ‘bull’ or ‘drive’ wheels. The bullwheels rotate as the cable loops are pulled by the system sails (in one direction and then the other). The turning action of the bullwheels drive attached mechanical ‘power take off’ devices such as generators, compressors, water pumps, etc.
The turning action of the bullwheels, drive power take off devices’ which in turn ‘convert’ the harvested kinetic energy into ‘usable’ mechanical energy. The converted mechanical energy can then be converted into other energies such as AC, DC electricity, and or; to other mechanical energies such as compressed air (via the use of air compressors in place of generators) and or ‘pumped-hydro’ via water pumps etc.
Compressed air and pumped-hydro are long proven energy storage systems and have been in use as high efficiency temporary energy storage systems for over 100 years.
Due to their ultra low cost and their ability to place very large sail areas into the flow, wind or flowing water, TW/SF systems will be viable for use in ‘low flow’ locations/conditions or in locations hitherto thought to be not viable for conventional wind or hydrokinetic harvesting technologies. This is an important factor as there are vastly more ‘low flow’ installation locations worldwide than there are high flow locations, making TW/SF variants truly universally install-able.
Hydrogen: the vehicle fuel of the future
Most people may not know it but virtually all gasoline engines can be modified / converted to operate on Hydrogen – and for very reasonable cost.
Because TW/SF systems will able to make ultra low cost Direct Current, it will be possible to make low cost hydrogen; hydrogen will then finally become viable as a vehicle fuel.
The ability to retrofit existing vehicles to burn Hydrogen, in place of gasoline, will have positive implications on reducing GHG emissions worldwide, why; because burning Hydrogen creates only clean potable water, and nothing else.
By compressing Hydrogen in vehicle-mounted cylinders, similar to how Natural Gas and Propane powered vehicles do it today, hydrogen becomes the ideal vehicle fuel of the future.
TW/SF System Installation:
When mounted in a vertical orientation on a boat, an airfoil is commonly referred to as a sail. When attached to airplanes, they are referred to as wings. When wings are installed in an underwater application they are typically referred to as hydrofoils.
Regardless of what one calls them, wings, sails or foils, their function remains the same; when a fluid passes over them, they create a lower pressure area on one of their sides; the resulting pressure differential pushes the sail/wing/foil toward the lower pressure side, hence, the ‘kinetic-to-mechanical’ energy conversion process.
The Swiss mathematician and physicist, Daniel Bernoulli was the first to identified the process; today we call it ‘Bernoulli’s Principle’.
The NASA video below explains how and why sails work, i.e. the physics that make it happen:
As you saw in the video above, the physics involved in the TW/SF process are proven.
Point of Fact:
The larger the wing/sail/foil, the more lift it can produce, in a clean energy generation application this translates into being able to make contact with more of the passing kinetic energy, this in turn, allows more usable mechanical energy to be made and then of course, more electricity to be produced.
A simple practical demonstration of the Shuttle Foil process you can experience for yourself: When driving on a highway, stick your hand out the window, turn your hand flat relative to airflow, notice that your hand stays put in one position, then create a slight angle of attack, up or down, notice the forces which immediately act on it; that’s lift being produced! That is a small scale demonstration of the same Shuttle foil effect that allows large scale TW/SF systems to operate!
So when sails are positioned in such a way so as to create an angle-of-attack in relation to the wind, they also create ‘lift’. Depending on the size of the sail, the angle of attack, and the velocity of the flow and even the velocity of the wing/foil/sail across the fluid, varying amounts of lift are produced.
As a simple way to get a very ‘rough idea’ of how much horsepower a sailboat sail can harvest, all one has to do is determine what horsepower engine the manufacture recommends or has installed at the factory. The installed horsepower will typically push the sailboat through the water at or near it’s design ‘Hull Speed’. So if a sailboat has a 50hp engine installed, that is what it needs to reach its hull speed.
Consider this: The SS Great Eastern was the largest commercial sail powered vessel in history. She was 211 meters, or almost 700 feet long, had a 32,000 ton displacement (that’s over 70 million pounds) and she was powered by over 5,500 square meters of sail! The Great Eastern could carry 4,418 passengers and crew from England to Australia and could achieve speeds of 26 Km/h under ‘sail power’ and this without the need for her on-board boiler-powered paddle-wheels or screw.
The M5, is one of today’s most modern super sailing yachts, she only has a single 88 meter tall sail. She has an 1000 ton displacement and can still achieve speeds of 14kts (25kph)! Using only her 2,600 horsepower engines, the M5 can only achieve 2/3 her ‘under sail’ speed! The M5 only has 3,400 sq meter of sail area. You get the point, a relatively small sail area can make a huge amount of power.
Hydrokinetic TW/SF systems:
The common Reaction ferry has been proving the hydrokinetic application of a variant of the TW/SF harvesting process – daily – and around the world, for over 500 years! Leonardo Da Vinci is generally credited with inventing the first ‘Reaction Ferry’ (which he used to get across the river in his home town).
Below are several videos showing several different types of Reaction Ferries in operation today:
The above example is the simplest rendition of the common Reaction ferry; total installation cost, only in the 10s of thousands of dollars! Harvesting energy does not get any simpler than this ‘pendulum’ variant of the Shuttle Foil process.
The ‘Reaction Ferry’ process uses the vessel’s hulls as ‘hydrofoils’, by creating an angle of attack between the flowing water and the boat hulls, the boat is pushed across the river using nothing but the river’s current as its means of propulsion. While this process may seem rather crude by today’s technological capabilities, Da Vinci’s Reaction ferry worked as good then as it does today. Why; because of the physics involved dictate it.
By adding state-of-the-art technology, including computer controls and modern hydrofoils to this age old and long proven Reaction ferry principle, it becomes possible to adapt this variant of the TW/SF process, to a hydrokinetic generation application; the net outcome is dirt cheap, clean, endless electricity.
As you saw in the above videos, the necessary infrastructure required to operate Reaction ferries is extremely simple, and ‘simple’ is good, as it means ‘inexpensive’ and ‘highly reliable’.
As is the case with any generation process, when direct operating/installation costs are low and output is high, an ultra low cost per kWh is had. When I say ultra low cost, I mean ultra low cost; the Reaction ferry at Lytton, British Columbia has a direct operating cost of circa 2 cents per hour!
While the world’s existing fleet of Reaction ferries only operate on rivers, there is no technical reason why adapted versions couldn’t operate across tidal flows.
The kinetic energy of a 30 ton Reaction ferry, ‘moving thru the water’ at a translational shuttle velocity of only 3 meters per second, would be 270,000 lbs (.5 x 60,000 x 9). As you can imagine, it takes a lot of ‘force’ to move 270,000 lbs of mass (not including water friction). If that ‘pulling power’ were used to turn a generator, a lot of electricity could be made from this simple process.
If an appropriately adapted/optimized ‘multi-hydrofoil’ equipped Shuttle Foil Reaction Ferry-type system were operated in a similar water flow rate but at a higher translational velocity of 6 meters per second, the adapted system would have an instantaneous output of roughly 1.5 MW (this, if the harvesting foils were operating at only at 40% efficiency and energy conversion components operating at only 80% efficiency and using only 50 square meters of foils).
While 1.5 MW may not seem like a high number to some, what one needs to bear in mind is both the cost of the installation required to produce that output as well as the direct operating cost of such an output; both of which are very low. The cost to produce similar outputs using conventional/existing systems would be in the ‘millions’ of dollars, whereas for Shuttle Foil systems, they would be in the low hundreds of thousands of dollars. That is a considerably lower cost per watt installed (and hence, cost per kWh produced) than the next lowest cost electricity generation process.
A little more perspective:
A tidal flow with a velocity of several meters per second and a flow of ‘10s of thousands of cubic meters per second’ will have an available kinetic energy content of 100s of MW. Rivers get their ‘energy’ from the earth’s gravity, for tidal flows, the (primary) energy comes from the gravitational pull of the moon. So when an energy harvesting process is introduced into the flow and some of the energy is extracted, the earth’s and or moon’s gravity immediately ‘re-energize the flow’, and this, no matter how many times the flow is harvested from.
In fact hydrokinetic TW/SF systems will only need less than a 100 meters of separation between harvesting systems to fully ‘re-energized’ the flow once again. To state the obvious: there is vastly more energy in repeatedly harvesting energy from flowing water, using Shuttle foil systems, than to ‘dam it’ and only harvest from it once (and far less costly and for more energy I might add).
Given the ready scalability of Translating Wing/Shuttle Foil systems, both in overall size and number of foils employed, a tidal flow SF system, having a span of several kilometers, operating dozens of large area foils, could easily have a ‘single system’ output of ‘high into the 10s of megawatts’.
Considering the world’s endless natural installation sites worldwide, i.e. using existing elevated natural terrain features such as valleys/hills (for wind and run-of-river SF systems) and coastal tidal flows (where there are highly predictable bi-directional water flows 4 times a day) vast amounts of kinetic energy can be accessed relatively easily, and for very low cost, all without environmental impact.
Remember this: The world is awash in an over abundant and endless supply of clean kinetic energy. In fact, with greater Climate Change will come more extreme weather, with more extreme weather comes more wind and rain (more river flows) hence, for those kinetic energy harvesting systems that can handle it, like the Shuttle Foil systems, they will only become more viable not less.
We encourage you to read the American Society of Mechanical Engineers (ASME) story on the Shuttle Foil approach published in their May 2017 online magazine: