Hydropower has a mixed environmental record. Large projects like dams that impound entire rivers are coming down across the west, as their impact on fish hatcheries and other ecosystems is now better understood. Furthermore, in addition to carbon-free power, one of the benefits was supposed to be flood control, but we are now seeing that the canalization and rigidity of a dam-controlled system cannot always cope with high water and while small-scale flooding is reduced, when it does flood, it is catastrophic. In the balance, large impound dams do not seem worth the environmental cost. Ditto the large, centralized power system.
In a future with less fossil fuels, the generation of carbon-neutral electricity will become even more important. Also, small, interconnected grids may be more reliable than large ones dependent on distant sources of power. Microhydro may be one way that communities can generate some electricity without impacting the ecosystem, emitting much carbon, or depending on nuclear decay, wind, or sunshine.
Microhydro systems are, as the name suggests, small. They can float on top of a stream or run on a small amount of diverted water instead of taking up the entire streambed. These systems only tap into a fraction of the power of a flowing body of water, which is a good place to be for anything that is sustainable in the long term: it is like living off the interest of an endowment and not touching the capital or a managed herd where plenty of animal are left to reproduce with only a percentage culled each year.
One such hydro system comes from the company Turbulant, in Belgium. Their promotional video, below, speaks for itself.
But there are many other ideas out there. YouTube is full of backyard tinkerers who have made small-scale generators that take a small diversion from a stream to generate a bit of power. Few would be able to run an entire house from such a DIY system unless they had a stream that could generate this scale of electricity available for tapping, but even generating a low level of energy continuously can add to a diverse microgrid supported by solar and wind.
Original hydropower was used kinetically, that is, the motion was used directly instead of for creating electricity. Think of a flour mill situated on a stream with a big water wheel. We have a more sophisticated understanding of hydrodynamics today as well as a huge communication network to help ideas spread and improve.
The most effective use of water power I have seen is to move water uphill. Ram pumps use the compression power of air under pressure and to push water uphill. It is hard to describe, but water coming down a short incline creates a bit of pressure that is pumped into a containment vessel. The pressure builds up and eventually is released to push a column of water up a pipe to a much higher place than the original source. Sound confusing? This video explains it clearly.
Another way to raise water is by using a spiral of tubing attached to a water wheel. By rotating the spiral, it pushes the water inward and increases the pressure. Again, a video shows the principle better than I can describe here. You may want to mute the volume on this one.
These are just a few ways that flowing water can be used to generate electricity and move water uphill. In the future, I’ll post about further kinetic uses of flowing water and other ways that small-scale, DIY projects can help power our future without fossil fuels.