Why haven't we dammed more rivers to create clean, cheap sources of power?

Question

PS - I don't mean flooding whole vallies; it is possible to dam a river without causing tremendous disruption to the river's flow or the eco-system. The dam could house turbines which allow water to flow through it - the down-stream part of the river would be completely unaffected!

Answer 1

OK... tricky one this,

There is no real reason not to dam rivers if the dams permit at least 40% water flow, now hear me out people...
i have my facts straight on this one.

Small turbines spaced out at 5 mile intervals might just do the trick... now each would only require a medium water flow to turn them so rather then a great big dam a wear might be sufficient... i think that's what you mean?

If you had a long river like the Thames or the Shenandoah or the Nile... about three to four hundred turbines set in pairs or in triples might = two or three coal fired power stations...

If the test location was up to the task you might be able to save a fair bit of power... if you connected the whole river network to the main power grid... yes i think it might work.

I know of a lot of my neighbors in England who use small turbine in local ajacent streams to run their lighting circuits.

Answer 2

To begin with it's not really possible to dam a river without tremendous disruption. Even Beaver dams do so though not, of course, on the scale that human dams do. As for your suggestion about simply placing turbines in the flow of water that would have two definite drawbacks. First flowing water represents energy. As that energy is transferred to the turbines it reduces the flow rate of the river. This will, over time, have definite consequences downriver. Also the amount of electricity generated would be wildly erratic and undependable and would take an absurd amount of energy to regulate thus dramatically reducing any real benefit.

Answer 3

A number of reasons:

In the case of a "high-head plant", think Hoover Dam:
- Constructing a dam for the purpose of generating hydroelectric power requires a huge initial investment.
- There simply aren't many rivers that meet the requirements needed to make construction of a plant viable.
- While hydroelectric power does produce clean cheap electricity, the act of building a dam to support the generation of hydroelectric power is extraordinarily harmful to the environment, so much so that the damage done to the environment by building the dam far outweighs any benefit that might be gained through hydroelectric power

In the case of "run of the river plant" which uses the flow of the river to spin turbines
- Requires a substantial initial investment to acquire and place turbines
- Produces much smaller amounts of electricity than a high head plant
- Output cannot be adjusted based on demand
- Dependent on local environmental conditions, such a area precipitation, a dry summer may mean less or no power generation

Answer 4

The folks down-stream, who may depend of the river for irrigation, recreation, or other uses will object to the dam.

The folks living in the area that will be underwater after the dam is built may be less than thrilled with the idea.

If these folks have enough political or economic clout -- the dam will be damned.

Answer 5

Environmentalists & Liberals don't want to dam rivers or build
wind turbines or drill offshore oil wells or build more refineries or build nuclear power plants and they want to shut down all coal & gas & nuclear plants and refineries and tear down existing dams.
They also want to stop importing foreign oil ...
HOWEVER...
They want cheaper electricity & gasoline and it is all the Conservatives & Republicans fault that they are not getting what they want...

Answer 6

Damming more rivers is not easy . You must find water sources to provide them, they also lost a lot of money and area

Answer 7

Because damning rivers seriously alters the surrounding area's ecosystem.

We as humans have already f***** up enough stuff, dontcha think?

Solar energy is the way to go.

Answer 8

I think a better idea is wind farms. They put some up recently in the bays off of Atlantic City.

Answer 9

wrecks lands, causes huge amounts of damnage to environment, etc... changes eco systems... why have they not eh?

Answer 10

thank you for the points