small hydro electric systems potential for isolated homes

Before installing a hydro electric system on your property, consider carefully your water rights, local permit requirements and the feasibility of the project; and do not forget to improve your home's energy efficiency as much as possible, prior to any decision.

To know if a small hydro power systems is feasible you need to determine the flow of the water on your site, and also its “head”, that is, the vertical distance the water falls.

Stream Flow

The “flow” is the quantity of water – measured in gallons per minute or litters per second… - falling from a potential microhydropower site. The flow varies over the year, and you should take it into consideration, especially if you are restricted on the amount of water you can divert from the stream.
Before deciding to install a small hydro power system you need to know how much water you can use to produce power; possible water rights for irrigation and other uses do not mean that you can divert water for hydro electric systems.

To determine your stream's flow, you can look for data from local offices, especially local water supply authorities. But you can also conduct your own measurements using, for instance, the bucket method.

This method involves damming the stream with logs in order to divert its flow into a container/bucket; if a 6 gallon container fills in 1 minute, than the flow is 6 gallons per minute.


The head (that is, the vertical distance the water falls) is measured in feet, or meters or units of pressure.

Obviously, the higher the head the better... You will need less water to produce the electricity, and smaller equipment. A head of less than 2 feet/0.6 meters can make a micro system unfeasible.

Estimating the power output

Once you've calculated the flow and the head of the stream, you can also calculate the power output of the stream in Watts. Just multiply the head by the flow and divide the result by 10.

Upfront costs 

The upfront costs of a micro-hydro power system vary widely; they are very site-specific, but do not expect prices below $30.000-$50.000 for, say, a typical 5 KW unit.

Take also into consideration maintenance costs ( typically low) and possible financial incentives to renewables; they can make the investment a lot cheaper.

Once calculated the costs of developing and maintaining your micro hydro system, you can divide them by the system's capacity (in watts), in order to know how much the system will cost you in dollars per watt, and compare it to the cost of the power in your area.

Energy Efficiency & Micro-Hydro Systems competitiveness

To make a micro-hydro system cost-competitive you should reduce your home’s electricity needs to a minimum, in order to install the smallest system possible.

That’s a key principle of energy-performance. To get it you should install proper levels of insulation all over the envelope of your house, and consider high-performance windows, lighting and appliances. Maintenance Costs
Hydro power is a very reliable source of energy, with low maintenance costs. But any micro-hydro system will need periodic professional maintenance.

See also: Micro Hydro Power Basics




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