Fresh Idea – Dockside Tidal Power

Tidal dock power

start of a sketch

Fresh ideas come along that might be worth a lot or a little; and some should be launched into the world because they may be needed now and shouldn’t wait for me to develop them fully. Sometimes, ideas have to flow and go. Maybe I can catch up later.

Of all the renewable energy sources, tidal power is one of the most predictable and ubiquitous – at least along shorelines. From my research, it would appear that I’ve come up with a variation that generates power without interfering with wildlife and also without having to be submerged in the corrosive environment that is salt water. Tides are inexorable. As long as something is buoyant, the rising tide will lift it, regardless of its weight. In its simplest form, my fresh idea (invention?) uses the tide to lift heavy objects; then, as the tide goes out, the potential energy of the lifted object can be converted into electrical energy. No need to guess about the weather and the winds. No need to check the latitude. No need to wait for the Sun to shine.

Some tidal power concepts rely on tidal currents turning submerged rotary machinery. They are successful but many people worry about wildlife hazards (though the rotation rates are so slow that it would be hard to get hit), and operators worry about maintenance and repair which is necessarily deep enough to necessitate divers and some danger.

Some tidal power concepts trade potential energy for electrical energy by trapping the high tide in a reservoir and using the outgoing current to power rotary machinery, as above. The machinery is easier to access, but the tidal reservoir takes up acreage and can also interrupt sea life.

Even with those caveats, I am fans of those systems.

Imagine instead, a floating dock like those we have in my neighborhood’s marina. As the tide goes in and out, the docks go up and down. If we tried to lift and lower the decks with electric motors it would require a ridiculous amount of energy. Yet, they go up and down about twelve feet every day.DSC_6079 My idea for Dockside Tidal Power leaves the docks as nothing but inspiration and as a physical foundation for the power generator. For discussion, imagine a weight that is allowed to slide up and down along a piling. The pilings are there to keep the dock in place. They are overbuilt for the purpose because all they do is make sure the dock doesn’t move back and forth too much. As the tide lifts the dock, it also lifts the weight. As the tide goes out, the dock drops. The weight drops, too; but the weight’s motion is retarded by any of a series of mechanisms that brake its motion and turn that braking action into power. In the simplest form, it only generates power as the weight descends. In the more advanced form, it generates power as the dock lifts. In a more sophisticated form, the dock is the weight with the proviso that the dock always remains in contact with the water. This latter form is more elegant, but also has some failure modes that could affect the use of the dock.

I came up with this fresh idea years ago. It wasn’t until a conversation during a land trust work party that happened to overlook the bay that the idea became defined well-enough to pursue. To me, the idea was simple enough that I thought that someone must have already developed it, and found some fatal flaw. After hours of research into tidal energy I became more of a fan of that version of renewable energy, and was surprised that I couldn’t find an example. One reason for posting this fresh idea is to find out if someone knows of such an application.

I did find a proof of concept that had nothing to do with tides. There are many gravity powered lamps. Raise a weight, let it slowly fall, transfer the motion to electricity through gearing and braking, and provide pollution-free light anywhere. One such device is a floor lamp that uses a 50 pound weight and a 58 inch drop to generate 40 watts for four hours. http://science.howstuffworks.com/environmental/green-tech/sustainable/gravity-powered-lamp1.htm A 55 gallon barrel weighs about 450 pounds, suggesting 360 watts. A typical American house needs 1.24 kilowatts. So, this could work for partial supply or backup; or gang four and power the house.

Given my Aerospace and Ocean Engineering background I’d thoroughly enjoy designing, testing, developing, and maybe even producing and selling such a device. If I had the money and the time, I’d turn off most of my other projects, build a team, and get to work building the device and the business. Unfortunately, I don’t have enough money which is I am working so many hours that I also don’t have the time. I considered crowdfunding the idea, but my recent crowdfunding campaign already delayed development and its lack of success makes me hesitant to embark on another campaign so soon. I could take the long and slow approach, something I am known for. Someone I’ve known for decades is also an inventor, and also has an extensive blog about the process and the probabilities. I think, however, that the world needs low-impact renewable energy now. Any delay simply so I can claim ownership is putting my needs over those of the coastal communities of the world. I think I should let the idea out there so it can grow, or be proven to have a fundamental flaw.

So, I pass along the fresh idea along with a sketch or two. If anyone wants to develop it, do so. Do it right and quick and pass it along, and no one will own it but many can benefit from it (if it works.) If you want me to help, definitely contact me. Of course, I’d like to help. Compensation would be appreciated, though. I ask for that from need, not choice.

There are too many variants to adequately describe here. I enjoy brainstorming and have had to pull myself back from generating yet another way to convert the power, arrange the system, and develop new applications. If you want more details, contact me.

My neighborhood has a marina, but I don’t use it. I don’t have a boat (and least not one that floats for very long.) When I bought my house I expected to buy a boat, too; but my Triple Whammy hit. I still hope to buy a boat, but that’s another story.

My neighborhood also has a beach, a twelve foot tide, a view of dozens of miles of Puget Sound to a hidden horizon. It is awesome to stand at the shore, look down to the horizon, and realize that quietly, every day, enough water flows in and out of that basin to cover square miles with feet of water – for free, predictably, without polluting anything, in a way that the sea life has evolved to live with. If we harness a small portion of that energy, we could probably power a city, or a marina could power a neighborhood, or at least someone with a dock might be able to power their house.

November Sunset

About Tom Trimbath

consultant / entrepreneur / writer / photographer / speaker / aerospace engineer / semi-semi-retired More info at: https://trimbathcreative.wordpress.com/about/ and at my amazon author page: http://www.amazon.com/-/e/B0035XVXAA
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One Response to Fresh Idea – Dockside Tidal Power

  1. Steve K says:

    Great idea. Better than the wave action testing being done off the OR coast.
    Just like regenerative braking on an electric car; rack and pinion to a transmission to convert slow rise and fall to fast rotational speed. Guts of a Prius. A way to switch from rise to fall, power each way. Batteries. Inverter. AC power.

    The problem will be regulatory, especially beside the water, but do-able. Imagine an entire marina, self powered including power to the boat slips… Or just one dock, units on each post.

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