When I bought my house, I didn’t realize that the stream that travels its acres is perennial and spring-fed … which seemed like the perfect scenario for a microhydro generator. These units make a lot of power all day and night, unlike solar and (usually) wind. It works by siphoning off a portion of water to run through a pipe, then through a generator, and then back into the creek. Voilà! So I did the measurements and found 140 gallons per minute, which is about enough for the purpose, but less than a 20 foot drop in elevation, which is the killer. Microhydro usually requires either high head or high volumes to pencil out, but I have barely the minimum of each.
At best, it would account for 20 percent of the house’s needs — not quite good enough for me to think too deeply about the capital expense or the fact that the town’s Conservation Commission probably wouldn’t allow the use. Other nearby commissions have also been unfriendly to residents employing or proposing it on their properties, even though microhydro is not a consumptive use and requires no dams.
I have some small consolation, though, knowing that all the electricity in this portion of my county’s grid is already 100 percent hydro, due to its proximity to the Deerfield River (one of the most developed rivers in the country, with small dams working up a good portion of its length from southern Vermont into western Massachusetts). Which is nice, in a way: the next nearest power plant to my community uses coal from a mountaintop removal mine in Appalachia, so this somewhat green power is welcome.
So I was interested to see news that small hydro is possibly on the verge of a boom, with new estimates of 30,000 MW of potential small hydro capacity in the U.S. alone. This would build on small hydro’s ubiquity in the industry, if the article is right that 80 percent of the existing hydro projects in the U.S. are low power (under 1 MW) or small hydro (1 to 30 MW).
The industry is saying it can get more power out of falling water without any more dams:
“The kind of projects we’re talking about would not involve large dams or any inundation of property. These would all be run-of-river projects,” says Hall.
This includes submerging weirs to raise the level of a river and create energy from the difference in water level, or excavating power channels that divert water through a power house and back into the water body. Depending on the size of the project, there are still some environmental concerns associated with these methods; however, they are considered to be a much more sustainable way of harvesting energy from a moving body of water.
Unfortunately, this sounds like more “industrial-light” uses on more portions of more rivers, but that certainly could be the lesser of two evils.
The rest of the article focuses on the regulatory hurdles that generally hinder new hydro projects. Also of interest here is mention of a company installing microhydro in wastewater treatment plants — not a bad idea, and one that Jon Rynn was kicking around in Gristmill recently. Maybe you could capture the heat of that water, too, either before or after the turbine …
In any case, I’m still thinking about attempting microhydro on my own seven acres: it’s sure to get more attractive as electric rates climb.
