This page falls squarely into two resources: water and energy. It is an important consideration as you evaluate water on a property because even if you have a great secondary year-round source of water, not all water sources are equally useful for all purposes.
In the northern latitudes of the American Redoubt, you won’t be getting much solar during the long nights of winter, so hydroelectric possibilities are definite asset.
The key term you need to think about when evaluating a water source for hydroelectric use is “head.” Head is merely the vertical height in feet of a column of water. It is why you see tall water towers around the countryside.
The weight of gravity according to the feet of height creates a pressure on all piping at the bottom. Because gravity only pulls down, and not sideways, height is the primary concern, not the size of the tank or pipe.
For the water tower, a pump uses energy to get water up there in the first place.
For hydro-power, the natural height will govern how much power you can generate with your water source. Your own personal Niagara Falls would mean solar panels are unnecessary. A broad, level stream is going to be almost useless for power generation, no matter how much is flowing by.
Current technology prefers at least 5 feet of head to get some power generation. That means when you look at water flowing across the land (seasonal OR year-round) try to eyeball how much drop in elevation you have from the water entrance at one edge of the property to the water exit at another edge. Imagine running a perfectly horizontal pipe from the water entry on the property to the water exit, with a 90 degree bend downwards just as the water exits the property. How high would that vertical pipe segment be at the end?
- Obviously more than 5 feet – you can do hydroelectric, the more height you have the more power you can generate.
- Close to 5 feet – have a professional survey done if it matters to you. You might get some hydroelectric power.
- Definitely less than 5 feet – you’d spend a fortune on equipment to get a couple of watts. Don’t bother unless cost is not a limit for you.
Some folks may object that it is possible to get power from a flat stream. Technically, they are right. But you need to think about cost-benefit. How much will you pay to squeeze a few watts out of a low and level river? If you have to talk to the state for water rights, it is unlikely you’ll get permission to construct a dam or divert 100% of the flow through your power generation. Remember also, that water follows the path of least resistance. And your generator’s resistance to turning is proportional to the electrical load it is trying to power. Even dropping a paddle-wheel in the river is not going to work out if it is easier for the water to flow around the wheel than pushing the blades.
Still, if you must consider some in-flow power generation, this website had some handy discussion, both for ideas and for calculations to see what might work and whether it is worth it.