at niagara falls why not build a modern paddle wheel mounted behind the falls that would not interfere with the scenic view, it should be just as efficient as as the turbine system.
209382
while it would be possible to use this method to generate energy from a fall, it would by so vastly inefficient that it would be impractical.  you would only be able to turn the wheel at a rate determined by the speed of the falling water, and while the water does have significant energy, most of that energy is disappated by the water changing direction during an impact.  this means that the energy captured by the wheel would only be a small fraction of the total energy of the water, compared with a much higher ammount for a turbine
79498
To answer your primary question, it just needs to be less expensive than fossil fuels...oil in particular.\n\n1.  Very few "direct" renewable sources are available non-stop.  A few would be tidal power, geothermal power and hydroelectric power.  There are many "indirect" sources, such as biofuels (ethanol, biodiesel, methane) which are the process of extracting energy from materials.\n\n2. Nothing is really practical (at this point) to compete.  Oil is still too cheap.\n\n3. Storage either in liquid fuel form or conversion to electricity offers the two easiest ways to move large amounts of energy.\n\n4. There's many viable technologies available today, but they are under continuous refinement to make them better, more efficient, less costy, and ultimately, more competitive\n\n5. This one is always fun.  Wind and hydroelectric don't pollute, but one is blamed for killing migratory birds and the other is hated for destroying habitats surrounding rivers.  Both offer the most promise as the next best source of energy compared to fossil fuels.\n\n6. Well, this depends on whether the consumer is in an energy rich or energy poor area.  If you live in an area where there's ample sun, good wind, and/or rivers you can dam up, then you're living close to where you can produce it.  If you can't produce enough energy from the sources immediately available to you, then you will either need to conserve more or import it.\n\n7. Politicians are likely only going to back solutions that prove to be overwhelmingly beneficial to their constituents.  You will get corn belt pols that back ethanol for the obvious positive economic impact that it will have on their areas.   Likewise, wind in areas that it could prove beneficial.\n\nThere is no one magic bullet for every energy need, that needs to be understood.  Some sources will win over others, based on the application and its availability.  But until oil gets more expensive (like over $100 per barrel) then most alternative sources just simply can't economically compete with today's renewable harnessing technology.
38101
Probably for the same reason there are lowriders and chopped motorcycles...cuz they can. In my day it was cubic inches and horsepower. For the life of me, I can't figure out why someone would spend thousands of dollars to make a car jump around like the devil is behind the wheel. But I do admire the hard work and innovation that goes into making it happen. Don't ask why, admire the work and move on if it isn't for you. C'mon...some of them are actually pretty cool :).
259574
Sometimes, rocking the boat is the only way to get attention. Sometimes the boat needs to change course because it's heading for dangerous waters. \n\nOne analogy about stability doesn't meant that things are better when stable.
431405
Efficiency is always output work over input work. The 600 lbf. load is irrelevant.
477105
Assuming you design it so the people don't reach terminal velocity, and you reverse the acceleration safely at the bottom, it just gives you a few more seconds of free fall.  Calculate the fall time and compare it to the fall time for a more traditional amusement ride.  Not enough difference to be worth implementing.
444637
Windmills are the best solution right now for renewable energy.  Hydroelectric plants destroy the environment much more then building windmills does, solar cells are toxic to make, and degrade after a few years.  To build a 400MW natural gas power plant and 400 MW worth of windmills (roughly 200 of them) costs almost the exact same amount of money.  Once the windmills are built, they require no fuel, and minimal maintainance.  On the other hand, a natural gas power plant is only operational about 2/3s of the time due to the need to maintain the very precise and expensive turbines, boilers, etc.  \n\nwhen people say windmills are an eyesore, putting them ~ 10 miles off the coast wont ruin anyones view, at 10 miles they will look like ripples on the surface of the water.  We have miles and miles of farmland that we could use in the middle of the country (not because there's lots of space there but the flat ground right after the mountains is ideal for windmills), given the relative footprint of a windmill, it wouldn't be a huge loss.  On top of that, by placing windmill on top of skyscrapers (if any of you have stood on an observation deck its always windy - and the structure is already there - you just have to go up a little higher)  the building would generate its own electricity, as well as then provide power to the grid.  \n\nThe downside of windmills is that they aren't efficient to put everywhere, so electricty transmission can become an issue.\nI dont know how many people have actually stood next to one of the bigger windmills, I find them rather aesthetically pleasing.
50126
They'd just use snow machines to make it. I'm sure they use em anyways for certain events.
120906
YES!!! Niagara Falls is soooo BEAUTIFUL. I'm in Niagara Falls. I just moved here. I LOVE IT HERE!!!
160185
if you want a huge turbine in your back yard, you could try using the wind for your energy
647365
Dams close up a river so the water stays in one place and forms an artificial lake. Canals are water passageways that boats carrying cargo can use to move around.
675290
Modern wind turbines can operate at efficiencies up to about 44% while the theoretical maximum efficiency is about 56%.  Tower height is very important and for a three-bladed system, increasing blade diameter increases power exponentially.  The wind is free but designs are optimized to increase efficiency to produce maximum energy for the installation cost.
120111
All the above. the taller wheels will need more power and torque to move.
334799
Cuts right thru the water better and the boat is faster...and it means a bigger boat which I like too...Oh, and it's like having a long waist line...it just looks so good...
553561
I cannot immediately give you a perfect answer BUT if you contact one of the manufacturers of wind turbines (a 5 second task with google) then they will almost certainly be happy to give you a LITTLE information from their technical guys.\n\nIncidentally the same works in reverse - which is why aircraft with props only have two blades.\n\nWork was done to find that ONE blade would be best if it could be balanced - hence some very curious looking "helical-style" blades on some BIG experiments wind turbines.\n\nThis is also conditional on a good design for the blades AND a given wind speed. For example, a twin bladed turbine CAN have difficulty starting in VERY low wind levles - when a multi-blade WOULD work. Yet once upto speed, the twin blade or helical blade would be most efficient.
202034
It's not a gimmick, it's an illusion , the same as the mtatlic hill, you're going down but it looks lie uoi are going backwards,something to do with physics, ask the physic' pro's for the deep, lengthy answer, they're good!
189896
To keep the world from tipping over.