Couldn’t putting small, eco-friendly dams in rivers produce power in a clean, cheap way?
February 12, 2010 by admin
Filed under Green Living Q & A
I’ve posted a similar quesiton in “news & events” –
Couldn’t a series of small dams with turbines in them produce energy? The power could be controlled by adjusting the number of turbines activated?
Yes, but it’s usually ecologists who oppose them.
Yes but dams alter the flow of rivers changing the landscape around them. Hydroelectric power is viewed as non-eco-friendly by some people because of this. Dams affect fish migration, and destroy terrestrial habitat by submerging it in the backed up region of water behind the dam.
As the guys above say, dams are likely to have a major adverse effect on the environment. Migrating fish can’t get past them, and they disrupt necessary flows of sediment. But you can do this without dams. The most environmentally friendly way to do it is diverting a part of a falling river, without dams. It’s called “small scale hydro” or “micro hydro”.
It won’t solve all our energy problems but it can help. In some cases it can power a remote house where running power lines would be expensive and solar is not an option.
Here’s a site with lots of information, links, and a forum where people discuss it.
You can Google “small scale hydro” for even more information.
I agree, I think it has been done successfully in countries such as Nepal to provide villages with light for example. Keeping it small scale seems to work.
As long as the turbines are small enough and don’t disrupt the rivers flow which is the biggest threat caused by dams effecting river ecologies ie reduction in flow rates, increased turbidity, increase in weeds becoming established on banks and release of cold anoxic water from the dammed water, all contribute to a disturbed ecology.
Some main reasons why this doesnt work very well are:
1. disturbance of the ecosystem, as mentioned in other answers.
2. small scale turbines require a lot of maintenance – the flow of water is variable – you have a normal amount, then a flood which is so much greater that the turbine is wrecked – so, you need a local person to service the system, and in many places that is not easy to arrange. And if the site of the dam is remote or inconvenient to access, they tend to go out of service and remain out of service for extended time periods because of the difficulty of getting service.
3. they arent too reliable – you have normal water flow, then a flood that wrecks things, and then a drought when there is low water and no electricity is produced. With big dams you can impound a lot of water and keep the power flowing through the drought.
4. they are subject to vandalism. In some places they have been installed and promptly stolen. In poor countries especially this is a problem, but lots of experimental installations in developed countries have also been victimized….
5. they are not cost effective compared to other kinds of alternative energy — a set of windpower generators is easier to locate, more reliable, less likely to be vandalized and has less environmental impact.
I don’t think there really is such thing as an ‘eco-friendly’ dam, unless you’re talking about the kind beavers make.
Damming drastically affects the surrounding terrain, and the creatures that live in the rivers. Fish ladders don’t work very well, as the disappearing wild salmon in the Pacific Northwest can attest. Yes, dams can produce a lot of power. But, aside from their environmental impacts, when you factor in our already problematic water-supply issues, they are far less desireable than alternatves such as solar, wind, and tidal, when it comes to long-term solutions to our energy problems.