Hydroelectric power uses the energy from flowing water to spin a generator and produce electric power. Small scale generators can be used to provide power to residents that may have a stream or river on their property.
If your property has access to a stream or river, you should first know flow and head measurements before you can begin looking at system designs and equipment. These measurements can help estimate cost and the size of the system.
Flow is typically measured in gallons per minute (GPM) and can be calculated a couple of different ways. One is to measure how long it takes for the current to fill up a container with a known volume. Another method is to measure a stream area's length and width and calculate how long it takes for an object to float from point A to B.
Head (or vertical drop) is water pressure created from the elevation difference of your turbine and the pipeline intake. Head is either measured in pressure or vertical distance and the higher the head, the greater the pressure and output will be.
A hydroelectric system will consist of many components, including an intake, pipeline, turbine, drive system and generator, among other components and control devices. These can all be sized and vary in size and complexity depending on flow and head.
Hydroelectric generators can produce a few watts to hundreds of megawatts (MW).
For sites with low flow and high head pressure an impulse turbine is often used. It works by water flowing through a nozzle and spinning a series of blades that spin on a wheel. Another type used for faster streams is the reaction turbine that is fully immersed and is used where flow is fairly consistent throughout the year.
This depends on maintenance and specific turbine type, but generally micro-hydro turbines will last around 15-25 years.
Micro-hydro systems require regular maintenance, such as clearing the intake to prevent clogs, greasing mechanisms, leak inspections, and belt tightening, etc.
Costs of micro-hydro designs (under 100 kW) will ultimately depend on the size and type of turbine and other equipment specific to your stream and system design. The cost of the turbine alone is a few thousand dollars.
Your system will need to draw power from another source when there is little power being generated from your hydro system. The most common and affordable way is to tie into the electric utility grid where you will use power generated from your utility during these times. Another option is to make use of a back-up generator.
Retail net metering allows an individual or business to self-supply a portion of their energy needs from on-site generation. In some cases, if all of the energy being produced at your home or business will not be used onsite, it can then flow back onto the grid rather than being wasted. The excess power can then count as a credit towards your energy bill. The value of each credit will be determined by your local electric co-op. In some cases a meter will be installed to measure the flow of energy in each direction.
It is suggested to contact your local electric utility to discuss what equipment they require.
Renewable projects produce two products: 1) Energy (kWh) and 2) environmental attributes (EAs). The EAs include the Renewable Energy Credits (RECs), as well any applicable carbon credits, or other benefits identified in the future. These two products can be separated in some instances.
One option is to install a disconnect switch, so, if an outage were to occur your hydro system could still supply your home with the electricity they are generating. Without this switch, the hydro system in question will be shut off. The switch is also necessary to maintain the safety of linemen working on the outage. Another option is to make use of a back-up generator on site. Make sure you discuss this with your local utility or an installer.
Interconnection is connecting your micro-hydro system to the electric utility grid in order to get power during times when your hydro generator is not providing enough power to meet with demand. To connect to the grid, typically at the point of service, some additional components will be needed including a DC (direct current) to AC (alternating current) power inverter, disconnect switches, distribution panels and a meter. Your installer will be able to determine how these components will be integrated into your system design. And it is always best to contact your local power provider when considering the installation of a micro-hydro system for your home.
To check if there are any rebates or incentives that you may qualify for, visit the Database of State Incentives for Renewables and Efficiency (DSIRE).
Your dealer/installer will usually contact the necessary governments and organizations that will be involved. You will also need to contact your local electric utility if your system will be grid connected. A list of our members and contact information can be found in the Member Directory.
Although micro-hydro systems are built to withstand freezing pipes and weather, equipment damage can sometimes occur. Many insurance providers will cover your system for these types of damages but it's best to discuss your particular coverage with your agent.
Your installer or dealer should be aware of most of the permits required for a residential micro-hydro system but it is a good idea to look over your local zoning ordinances, building codes, and federal and state laws.
Many factors have to be considered when calculating payback time. The initial cost of purchasing and installing your system will greatly depend on the size and type of system. You will need to calculate your home's power requirements and estimate electricity prices during the life of your system. There are many online sources that calculate an estimated paypack time but it's best to discuss your system costs and payback times with your installer or dealer.
Most importantly if you are connecting to the electric utility grid you will need to sign an interconnection agreement with your local utility. The agreement specifies terms and conditions of your system being connected to the grid as well as connection specifications and permits required. Some homeowners associations may also have agreements for connecting a micro-hydro system.
As a wholesale power supplier, Tri-State does not serve retail consumers and therefore does not have programs in place to directly assist individuals with the up-front cost of a micro-hydro installation. However, through its renewable energy program, Tri-State enables and offers incentives to its member co-ops to develop local renewable resources. You will need to contact your local electric co-op to learn how those programs can be applied to your project.