Hydropower has a Dam-less Future (VOA)

[jpak]

http://www.voanews.com/english/2006-05-05-voa41.cfm

<snip>

In the U.S., where hydropower represents eight percent of the electricity for the country, there are no plans to build any large new dams in the future. However, there are plans to use more of the existing dams to generate electric power.

Linda Church Ciocci is the Executive Director for the National Hydropower Association. "Hydropower is only on two percent of all the dams of the U.S. That means there is 98 percent of the dams that are currently in the U.S. that have no power generation on them whatsoever. So there is a tremendous growth opportunity there in the existing facilities."

<snip>

Trey Taylor is the co-founder and president of Verdant Power, a new project of underwater turbines that look like wind power turbines but work with underwater currents. "It has been tested extensively in Pakistan, Chesapeake Bay and in New York's East River. As a result of those test which exceeded our expectations, we are putting the world's first field of underwater turbines in New York City."

Taylor says the potential for the new technology in rivers and oceans around the world is extensive. Just in the U.S. the interest is increasing rapidly.

<more>

[flamin lib]

1. Cool! This could be installed behind the exhaust of cooling water

for natural gas powered generators to re-capture lost thermal energy. Wonder how long it would take to amortize the cost of installation.

[phantom power]

2. These capture mechanical energy, not thermal energy.

(Unless I'm just completely missing some important point here)

[flamin lib]

3. Yeah, but the cooling water is channeled into the generator and

returned to the lake/river in a moving stream. The energy needed to cool the plant (pump the cooling water) could be re-captured in the exhaust flow.

edited to add:

And in the inlet stream as well!

[Dead_Parrot]

4. Depends...

I'm guessing at least one of these flows is pumped, so you'd be in the realms of perpetual motion to tap into it for power.

[flamin lib]

5. I don't anticipate a net gain in energy

production, just a reduction in loss. Like capturing waste heat for re-generation.

If the cost of generation is X per KW the new cost would be X minus the recovered energy after the cost of the turbines and operation. If they're as efficient as the website indicates and the generating plant is moving the water anyway why not harvest as much of that kinetic energy as possible?

Let me try another analogy. Car engines once used fans attached to the crankshaft to draw air past the radiator. The fan turned all the time needed or not. It took as much as 2 HP to turn that fan. Meanwhile the generator/alternator produced more electricity than needed to operate the electrical system. Modern cars use electric fans that operate only when needed, i.e. only when the engine is hot and the car is stationary. The 2 HP now goes to improved performance. The alternator adds drag to the system only while it is powering the fan so the net results are something less than 2 HP but more than 0.

Just a thought.