Disadvantages of a "small dam"?

[Obamot]

For those who are interested in that, I do not know if you have seen on Euronews these dam projects with just two bodies of water (one upstream the other downstream) in correlation with wind power.

At night (for example) the wind turbines pump the water back upstream. When there is no wind, it is the water that takes over and makes it possible to produce electricity. Thus the electricity production is almost never interrupted !!

I think it's great, you still had to think about it ...

[sen-no-sen]

For those who are interested in that, I do not know if you have seen on Euronews these dam projects with just two bodies of water (one upstream the other downstream) in correlation with wind power.

At night (for example) the wind turbines pump the water back upstream. When there is no wind, it is the water that takes over and makes it possible to produce electricity. Thus the electricity production is almost never interrupted !!

I think it's great, you still had to think about it ...

I saw the report in question, very interesting indeed.
The principle is that of a giant "flush", it is an excellent device to overcome the peak of consumption, moreover this process also exists in Sweden it seems to me.
In terms of response time to energy demand, it is much more efficient and virtuous than conventional thermal power stations.


To come back to the impact of dams, small or large, the disadvantages relate mainly to the impact of aquatic life, many fish are blocked upstream of the river (some dams are equipped with "stairs" to allow migrating fish to spawn, but the device is still a gene for them).
Likewise, since floods are regulated, alluvium tends to accumulate upstream of the dam.
Safety is also a disadvantage because of the "water drops", which have caused a number of accidents, sometimes fatal.
EDF to dismantle a certain number of small dams because of the negative impact on wild fauna and flora, moreover the output of such devices is quite low.

[Christophe]

I think it's great, you still had to think about it ...

Uh there is no difference with what currently exists on a country scale. This is the job of the network manager ...

It has been 75 years since the Vosges power station of Lac Noir / Lac Blanc has pumped water back at night during off-peak hours to "balance" the load ...

code: Select all

http://fr.wikipedia.org/wiki/Lac_Noir_(Vosges)

A hydroelectric plant was built there between 1928 and 1933 by René Koechlin. This is the first Pumping / Turbine Energy Transfer Station (STEP). Lac Noir is connected to Lac Blanc (120 meters higher) by a pipe which allows electricity to be produced by turbines at peak hours, alternating with recharging of Lac Blanc, which is higher, by pumping during off-peak hours. It develops a power of 80 MW.

[Christophe]

in addition, the efficiency of such devices is quite low.

Source? What performance are you talking about?

Speaking of "pure mechanical" efficiency with renewable energies is frankly not the main criterion.

The main criterion is the economic profitability (financial return) compared to a fossil solution.

Example: a renewable technology which has 1% efficiency but which costs 1 € per installed kW (let's dream a little) is "infinitely more interesting" than a solution which has 70% efficiency but which costs 3000 € per installed kW!

[Obamot]

Yes it's true, it is also done here (ie Le Lac Noir as you quote it but also La Grande Dixence and wherever it has been possible) except that pumping water consumes energy, whereas in this case it is supplied by the wind turbine ... that's what I meant.
Because pumping water to supply a hydroelectric dam, using energy supplied by a nuclear power plant ... It's messy ...
This means that this configuration can now be established on sites where it would not be very profitable otherwise and where there is no longer a need for a high-flow river to supply a dam (that's how I see it and as it was described in the report). But that's just my opinion.

[sen-no-sen]

in addition, the efficiency of such devices is quite low.

Source? What performance are you talking about?

Speaking of "pure mechanical" efficiency with renewable energies is frankly not the main criterion.

The main criterion is the economic profitability (financial return) compared to a fossil solution.

Example: a renewable technology which has 1% efficiency but which costs 1 € per installed kW (let's dream a little) is "infinitely more interesting" than a solution which has 70% efficiency but which costs 3000 € per installed kW!

I mentioned the performance of small dams compared to the impact on the environment and on the beauty of a site, I was not talking about the "technical" performance.

[Christophe]

Uh, disagree: the mills cause much less concern and impact on the environment than concrete dams several tens of m high ... No?

Obviously it takes a lot more to produce a dam ... but X * 0 = 0

[sen-no-sen]

When I spoke of small dams, I mentioned the small concrete installations, there was no question of the mills of yesteryear, which are very beautiful!