Dam-less HydroPower

In general, hydroelectric power is derived from the height through which water falls. When we build a dam, we are doing the equivalent of bringing two points along the river close together, to create some desired height.

Think of it in terms of the basically gentle slope of a riverbed, and Points A and B along the length of that riverbed, with B being downstream of A. If we drew a horizontal line from A to B, how high above B would that line be located? Well, when we build a dam at B, the water-level behind the dam is exactly that horizontal line connected to A.

So, it can now be understood that we don't actually need to build the dam! Instead, let's put a large Tunnel Boring Machine at Point B and set it to dig horizontally toward Point A. Once we are beneath Point A, we bore vertically to connect to the upstream part of the river. Now all we need to do is put a turbo-generator into the bore-way, and we will be generating hydropower, exactly as if we had built a dam at point B.

There are some advantages and some disadvantages to this Idea. The main disadvantage is that we won't want to send the whole river down the borehole at Point A --but in terms of a dam, essentially the whole river does generate power at Point B. The two main advantages are that fish are free to swim the whole river (we merely need screens to keep them from going down the bore hole), and that we can build these borehole hydropower systems all along the length of the river, without any need to look for special places to put them (like high canyon walls are needed when building a dam).

I would like to think that the net effect is, we could actually generate more total hydropower from this dam- less system, along the length of a river, than from the normal damming system. To be determined, of course!