Micro Hydro Power Plant Design
If you have water flowing through your property, you might consider building a small hydropower system to generate electricity. Microhydropower systems usually generate up to 100 kilowatts of electricity. Most of the hydropower systems used by homeowners and small business owners, including farmers and ranchers, would qualify as microhydropower systems. But a 10-kilowatt microhydropower system generally can provide enough power for a large home, a small resort, or a hobby farm.
Micro Hydro Power Plant Design
For example, some stand-alone systems use batteries to store the electricity generated by the system. However, because hydropower resources tend to be more seasonal in nature than wind or solar resources, batteries may not always be practical for microhydropower systems. If you do use batteries, they should be located as close to the turbine as possible because it is difficult to transmit low-voltage power over long distances.
Impulse turbines, which have the least complex design, are most commonly used for high-head microhydro systems. They rely on the velocity of water to move the turbine wheel, which is called the runner. The most common types of impulse turbines include the Pelton wheel and the Turgo wheel.
Reaction turbines, which are highly efficient, depend on pressure rather than velocity to produce energy. All blades of the reaction turbine maintain constant contact with the water. These turbines are often used in large-scale hydropower sites.
Because of their complexity and high cost, reaction turbines aren't usually used for microhydropower projects. An exception is the propeller turbine, which comes in many different designs and works much like a boat's propeller.
Propeller turbines have three to six usually fixed blades set at different angles aligned on the runner. The bulb, tubular, and Kaplan tubular are variations of the propeller turbine. The Kaplan turbine, which is a highly adaptable propeller system, can be used for microhydro sites.
Conventional pumps can be used as substitutes for hydraulic turbines. When the action of a pump is reversed, it operates like a turbine. Since pumps are mass produced, you'll find them more readily than turbines. Pumps are also less expensive. For adequate pump performance, however, your microhydropower site must have fairly constant head and flow. Pumps are also less efficient and more prone to damage.
The waterwheel is the oldest hydropower system component. Waterwheels are still available, but they aren't very practical for generating electricity because of their slow speed and bulky structure.
Farms often have easy access to lakes and ponds as well as naturally occurring streams and rivers. When farmers possess the rights to use the water resources that are contained on-farm, they usually face fewer obstacles both in permitting and in the efficient use of farm-scale hydropower. Hydropower can be a continuous source of energy as long as enough water is flowing, and this publication will discuss hydro energy and how to sustainably harvest it. It will not focus on waterwheels, although many of the informational resources that will be discussed are also relevant to developing waterwheel projects.
Electrical power is measured in watts (W), kilowatts (kW), or megawatts (MW), and mechanical power is measured in horsepower (HP). If a turbine generates 150 watts continuously for an hour, it will have generated 150 watt-hours, or 0.15 kilowatt-hours (kWh). Hydropower systems for homes and farms generally have power outputs of less than 100 kilowatts. For convenience in terminology, this scale of hydropower is referred to as micro-hydro.
In order to adequately assess the minimum continuous power output to expect from your hydropower system, you will have to determine the minimum quantity of water that will pass through it. For this reason, it is important to know both the minimum flow rate of your stream and what portion of this flow you can use for power generation. It is always important to divert minimum flow for power generation, especially when it will have an impact on fish migration and stream ecology.
The environmental impact of micro-hydro systems is usually small but by no means absent altogether. When water is diverted or dammed, or when structures installed in the stream channel interfere with the natural flow of the water, there is an environmental impact. However, compared to large hydropower dams, micro-hydro systems have a smaller footprint and generally lower environmental impacts. Even so, there are several local, state, and federal agencies that may want environmental impacts to be assessed for a micro-hydro project.
Roger and Shelley Barton own and operate Barton Farm in Ferron, Utah. The Bartons farm 120 acres of alfalfa and mixed grasses used for horse hay. They irrigate with a center-pivot irrigation system. Diesel fuel is a large expense in operating a center pivot. The Bartons needed to reduce fuel costs and still follow their irrigation schedule. By using a Cornell hydro turbine to produce mechanical power, the Bartons eliminated their irrigation fuel costs while also reducing the environmental impact of burning fossil fuel.
A key part of any micro-hydro project is obtaining the necessary permits from local, state, and federal agencies. Although the permitting process may appear burdensome, it is intended to protect the water resource and its users, including the fish, plants, and animal communities that also use the water. It is best to identify all the necessary permits and approvals to develop a hydro resource very early on in the process. Doing so will help you avoid wasting time in planning your micro-hydro project.
The first step is to determine the ownership of water rights for the resource being considered. Law pertaining to water rights varies greatly across the country, and a close examination of regulations in your area is important. Talk with any other micro-hydro project owners in your area to learn what they have done. Generally, you should not assume that because you own the land, you also own the water that runs across it. In many states, it is possible to buy land without water rights or to buy water rights without owning the land along with them. A property owner downstream may own the first right to use water upstream from that property, or the water may be owned by several downstream users, with each allowed to take some percentage of the flow. In many states, the fact that your hydro system will only use, not consume, water will not be enough to avoid needing a permit; you must have the legal right to use the water and obtain a permit to use it in many areas. The water rights for particular sites may go back a great many years, and researching old records may be necessary to determine the true holder of those water rights.
A second step is to secure a water-use permit, which, in some cases, may be required from both state and federal agencies. In some states, having the legal right to the water is all that is required. In other cases, an additional permit is required referring to a specific intended use. Here again, most water-use laws are oriented toward agricultural uses, and questions may arise relative to their interpretation in the context of a micro-hydro project. Often, the actual installation work must begin within some time period or the permit will expire and must be applied for again.
The Federal Energy Regulatory Commission (FERC) is the agency that issues exemptions and licenses for non-federal hydropower projects. FERC also provides guidance concerning state and federal agencies you will need to contact regarding many of the environmental and historical issues related to a hydropower project. Because most hydropower projects have tended to be very large, with significant regulatory issues involved, the FERC licensing process has historically been a lengthy effort. Because of growing interest in small and micro-hydro projects, FERC provides permitting guidance online through the Small/Low-Impact Hydropower Program to help small hydropower projects move quickly through the licensing process. (See the Further Resources section in this publication.) FERC has the authority to issue exemptions for projects under 5 megawatts (all micro-hydro projects fall under this threshold) and when projects use existing conduits (such as an irrigation canal) being used for purposes other than hydropower. Applying for an exemption is free but requires patience. The average wait from submitting an application to receiving an exemption is six to 12 months.
Small- and low-impact projects may have a simpler permitting process than larger projects, but that does not mean they are exempt from the jurisdiction of such federal and state agencies as the Corps of Engineers, fish-and-wildlife agencies, and other agencies that establish building codes. Many small hydropower projects have been developed without going through the official permitting process required by FERC and other agencies. There are risks associated with doing so, however, including the possibility of an order to stop operating the system you have just paid to install. It is recommended that developers of small hydropower projects determine whether they are subject to FERC and other local, state, and federal regulations before developing a hydropower site.
Permitting may be the most cumbersome and time-consuming process of your small hydro project. The process may go more smoothly if you review the FERC Small/Low-Impact Hydropower Projects website, communicate regularly with relevant agencies, and take the time to provide a comprehensive application package.
Impulse turbines generally use the velocity of the water to move the runner (or wheel) rather than using pressure, as is in the case with reaction and propeller designs. Consequently, there is no suction on the down side of the turbine, and the water simply falls out of the bottom of the turbine housing after hitting the runner. Impulse units are generally the simplest of all common turbine designs and are widely used in micro-hydro applications. There are three common impulse runners: the crossflow turbine, the Pelton wheel, and the Turgo wheel. 350c69d7ab