Hydrokinetics: Short Introductory Video
In our continuing series of videos, whose purpose is to introduce newcomers to the subject of renewable energy, I offer this short piece on hydrokinetics, featuring a discussion of the strengths and weaknesses of the idea of extracting energy from moving water.
Though this sounds simple – and mankind has been harnessing that simplicity for thousands of years, it gets tricky now that there are seven billion energy-starved people on this small planet, and we’re desperately looking for sustainable ways of providing that energy.
Indeed, it’s not as easy as it seems. Anytime we insert a device into moving water, we face immediately a variety of issues, both ecological and logistical. I.e., we’re both changing the natural habitat in some ways that are hard to understand completely, and we’re also setting ourselves up to face huge costs associated with maintenance, as devices rust, and encounter things like biofouling, shifting current patterns, dynamic sea- and riverbeds, etc.
Hope you enjoy.
[youtube http://www.youtube.com/watch?v=P9xxcHdO2NE]
Sorry Craig, almost every device you mention depends on the worst possible way to draw energy from elevated water, and that is the use of turbines. Until we leave this old technology behind we will continue to struggle in the use of hydro kinetics. The sin is in elevated kinetics. When you accelerate water you are accelerating a huge mass, and because you can not compress this stuff, you must allow it to leave your turbines at the same rate it enters. All accelerated mass is lost in this dismal process. 15% efficiency at best, unless you pump / store water like in the Niagara system where your efficiency drops below 7%. What a waste!! If you use that elevated water to compress air, it will not be accelerated in the process so the vast majority of energy can be collected and stored until ready to use. (See the law of thermodynamics to help understand what I speak of). Now you can collect the water as fast as it is made available and use whatever elevation you have to work with to compress and store air, releasing the water on its way, then you could store that energy for eternity. (I know, nothings forever. 100 years anyway.) No more dams needed except for flood control. Tear the rest out and let mother nature reclaim the rivers. (I would not need to dam any river for this process.) Then what, air turbines? Hardly. Displaced water mass has a displacement force of 62 pounds per cubic foot. 100 cubic feet will put a force of 6200 pounds into a trans / gen set like those used in wind turbines. Need more electricity, add more air, need less, reduce the air going into the machine and store it until needed. This allows for a rapid change in load supply, unlike any turbine. I can stall one of these units (a HYPEG) with a brake and turn it on at full output in seconds, unlike steam turbines. No wasted energy here, zero standby losses.
This is how we are going to solve all energy needs forever on this planet. Add the amount of cubic feet of water running down the Mississippi alone could power the entire US continent, not that there aren’t thousands of other sources making that unnecessary. But do not forget to measure every foot of evaluational change in that calculation. Then Fundy bay, the Niagara River, Hoover Dam, Mt Morris in NY, the Erie Barge Canal, the Nile river, the Grand Coulee, the Yangtze river and on and on. And every cubic foot of water will generate 3/4 a cubic foot of air to enter a water tank displacement with a simple 30 foot elevation. Even if that natural water elevation is over a twenty mile run, we can still use it to compress air. Elevation is elevation, no matter how far the run is. We can even use the waves on shore to compress huge volumes of air. Or wind turbines. Or solar panels. Or waste heat from thermal processes like smelting metal if you think you need to. More compressed air than we would ever need, without another gram of fossil fuel being burnt.
This is a new science and if you would like to speak directly to the scientist / engineer who developed this new device I can arrange it. Its here now, all you have to do is ask. It is how all electricity will be generated in the future, through the use of compressed air generated by Mother Nature until the end of Mans time on this planet.