Running water has been used for decades to generate power on an industrial level and many homes get their grid power from hydroelectric power plants. However, direct hydropower is not a viable source of alternative energy for the majority of homes, as it requires a source of running water close by. But if you are lucky enough to live next to a stream or river, or have a cabin/vacation home by one, installing a hydropower system gives you access to the most practical source of alternative energy out there.

HOW IT WORKS

Home hydropower systems, most commonly called micro-hydropower systems, use the force of running water to generate electricity via an alternator. Most modern home kits are "run of river" systems that use a pipe rather than a dam to power the alternator, which has less impact on the surrounding environment. In these systems, a pipe redirects a small part of the stream over a turbine or waterwheel, using gravity to pressurize the water through a nozzle for increased power. As the turbine or waterwheel spins, the mechanical energy is then converted to electricity by an alternator and stored in batteries or transmitted directly into the home.

REQUIREMENTS

The amount of electricity generated by a micro-hydropower system depends on two main aspects of the stream - the vertical fall (called "head") and amount of water flow (measured in gallons per minute). As a rule of thumb, the minimum requirement to install a micro-hydropower system is a fall of 3 feet and a flow of 20 gallons per minute. However, this is not set in stone as the fall and the flow is a ratio that can fluctuate since a higher fall will generate the same force with less flow needed and vice versa. Because of this, each home hydropower system must be custom built to match the stream's attributes for maximum efficiency.

Due to the sheer amount of water fall and flow needed to supply the constant peak power required for alternating current (AC), most home systems will utilize a battery system that stores the electricity generated as direct current (DC) and use an inverter to convert it to AC for home appliances. For homes that do not have a constant water flow, micro-hydro systems can still be connected to the grid so that the home has access to electricity even in the dry seasons.

If you only have seasonal water flow, though, a good idea would be to pair a micro-hydropower system with a solar power system. During the rain months, you will generate power from the turbines and in the dry season, you will have enough sun to power your home through the solar panels. It covers all your bases and both systems can even share the same battery system.

COST AND INSTALLATION

Because of the number of variables that need to be taken into account, most micro-hydropower systems are custom installed by professionals. The cost of the system will depend on your terrain and will differ greatly for each home. Depending on the lay of the land, you may only need a few feet or a hundred feet of piping. As always, it is a good idea to have a few estimates done to make sure you are getting a competitive price.

Do-It-Yourself kits are also available and can be a cheap alternative. Buying separate parts to make your own system, however, should only be attempted by those with a good understanding of electrical systems as you will need to select a turbine with the proper attributes (horsepower and speed) to match your generator. Even though DIY systems can be quite easily installed (some only require a few feet of piping) they will rarely match the efficiency and power output of a professionally installed system that factors in the many aspects of the terrain and environment.

In addition, there are also a growing number of people creating homemade hydropower systems using random parts available to them. There are many dangers of this as the created system may have adverse effects on the environment if the wrong parts are used (you wouldn't want to contaminate the water with rust or grease, for instance). But for those with a technical background and a love for invention, there are many articles online that have schematics for building systems that utilize household items and everything from car alternators to centrifugal pumps run in reverse to harness the power of flowing water.

When properly installed, micro-hydropower systems can last many years. Regular maintenance is required to ensure there are no buildups and blockages to the pipe and in most cases, the pressurizing nozzle will need to be switched around each season due to fluctuating water flows.

PERMITS AND TAX CREDITS

As hydropower systems have the potential to greatly impact the environment (you are diverting water from an establish ecosystem, after all), you will need to check with your county engineer or state energy office to see if you need a permit or not to install the system you want. As each state limits the amount of water you can redirect, you will also need to check on how much water you can use for power generation.

In most cases, small home systems that have minimal redirection and aren't planning to net-meter (sell electricity back to your electric company) will require little to no paperwork. In some cases, your state may even offer tax incentives for micro-hydroelectric setups as you are investing in a renewable energy system.

The beauty of hydropower is that it does not depend on the weather like solar and wind systems and it generates usable electricity instead of just heat and hot water like geothermal systems. With a decent stream of water, micro-hydropower systems can easily generate more than 10 kWh and a single water turbine would supply enough power to a home or farm to completely go off the grid. While the availability is more specific to location than other forms of alternative sustainable energy, hydropower is a lot more reliable and should definitely be taken advantage of if you have access to flowing water.

If you are interested in further information on installing one of these systems, check out these books: