Air is constantly on the move. In some areas of the country, it provides a highly reliable source of mechanical energy. Fortunately, humans have invented an amazing array of devices that can harness the energy of the wind and put it to practical use. Wind energy is one of the cleanest and cheapest energy technologies in the world. With the interest in renewable energy growing, it’s no wonder that the popularity of using wind energy is rising fast.

Wind energy systems generate electrical energy by harnessing the power in wind using machines called wind turbines. Wind energy can be produced for a single home or can be produced in quantity and distributed to the electric grid.

As with solar, there are considerations in using wind energy. The most important and most obvious one is the need for a breeze. Yes, air is always moving, but wind is needed to turn the blades of the turbine fast enough to produce electricity in quantity. There are particular areas in the U.S. where the air flow is rapid enough to do just that. In Middle Tennessee, high elevations or land far from cities (rural properties) are ideal locations. High elevations provide you with higher wind speeds.  Whether the high elevation is natural or provided by a wind tower doesn’t matter.  However, wind towers need some acreage and rural land is the ideal location for them. The Department of Energy Efficiency and Renewable Energy suggests at least one acre of rural land.

Now let's discuss wind turbines. Wind turbines, like aircraft propeller blades, turn in the moving air and power an electric generator that supplies an electric current. Wind speeds typically need to be sustained at a minimum of 10 miles per hour to turn the turbine fast enough to generate electricity. In most cases, the longer the turbine blades the more energy it can capture from the wind and the more electricity it can generate. However, sometimes in a lower-wind-speed area, a turbine with smaller blades can end up producing more energy than a larger rotor because it takes less wind to spin the smaller generator.  And let’s not forget another major factor: tower height.  The higher the turbine, the more energy it can capture because, remember, wind speeds increase with elevation.  Scientists estimate a 12% increase in wind speed with each doubling of elevation. And with a doubling of wind speed comes an eight-fold increase in power potential.

To help determine the suitability of your site for a small electric wind system, you need to estimate your site's wind resource. The wind resource can vary significantly over an area of just a few miles because of local terrain influences on the wind flow.

Since we are in no danger of running out of wind, using wind power in combination with micro-hydro or solar (or both) can provide you with plenty of electricity to power your home free from the utility grid, and to reduce your carbon footprints and monthly power bills. And remember, if you stay connected to the “grid,” any additional energy your system produces can be sold back to the utility company. Wouldn’t that be a change – having them pay you?

Anyone who has a river or creek nearby has the potential to supply their own clean, efficient electricity.  And in this day and age, an opportunity to create your own power is an enviable position to be in. Streams offer a renewable natural source of energy that, if done right, can have little or no impact on the environment.  Micro-hydro power, which is hydro power for home-based systems, is probably the least known of the off-grid energy systems, but it has the potential to produce the most power.  Also, with the right site, flowing water can be more reliable than wind or sun – especially in remote wooded areas (our specialty!).

Hydro power is based on simple concepts. Moving water turns a turbine, the turbine spins a generator and electricity is produced.  The amount of power that can be produced is dependant on two factors: the stream flow (how much water runs through) and the drop (head) which provides the pressure behind the flow. There are varying opinions on how much water needs to flow to operate a successful micro-hydro system, but it seems that at least 2 gallons per minute of flowing water and a good drop; or at least 2 feet of drop and 500 gallons per minute of water flow are needed. (See links at end of article on how to measure the water-volume flow rates.)

Micro-hydro systems function much like the old grist mills. They run alongside a river or stream, diverting a small amount of water into 2”- 4” plastic pipe which then jets through a nozzle and spins a turbine. The water is then returned to the source. These cause much less eco-damage than dams because they don’t interrupt the entire water flow or create a pool of water in a reservoir. They are built with simple technology, making it possible for people with basic training to maintain their own power systems.

In planning a micro hydro system, accurate site assessment is vital because it not only determines the micro hydro energy potential but also helps determine the perfect location for the apparatus to be installed.  The terrain surrounding the stream must be suitable for running a length of pipe from the proposed intake structure to the powerhouse location. It also requires access for construction and maintenance.  (See links at end of article.)

There is an abundant supply of streams that criss-cross Middle Tennessee making micro-hydro power very feasible.  You can take just about any creek, spring, pond, or river and turn it into clean, efficient electricity. Of course, it’s best to have a site with year-round running water, such as Factory Falls to the left or Canyon Falls below, but isn’t that exactly the sort of place we’d like to live in anyway? And if the site doesn’t have a consistent flow, that’s okay, in areas with high rainfalls in the winter and plenty of sun in the summers, such as Middle Tennessee, hydropower combines naturally with solar for year-round self-sufficiency.