Hydroelectricity
Hydro power systems use running water turning a turbine to produce electricity. A micro hydro plant is one that generates less than 100kW. As technology has improved in small turbines and generators, producing hydroelectricity has become more attractive even from smaller sources of water.

Benefits
A micro hydro site with a good source of hydro can generate a more reliable electricity supply at a lower cost than other renewable technologies. Total system costs can be high but often less than the cost of a grid connection and with no electricity bills to follow.

If a system is to supply electricity to off grid applications, the power is used for lighting and electrical appliances. When power exceeds demand, space and water heating can be supplied too.

How it works
Hydro power systems convert potential energy stored in water held at height to kinetic energy (or the energy used in movement) to turn a turbine to produce electricity.

The water flow rate and height of a body of water will dictate the energy available. These are divided into low head, medium head and high head, where the height drop is greater. The output of the system will depend on how it converts the power of the water into electrical power. Maximum efficiencies for small scale systems are between 60-80%.

Is it suitable for my home?
To benefit form Hydro power, the source is required to be relatively close to where the power will be used or to a suitable grid connection. Systems can be connected to a stand alone (off grid) power system or the main electricity grid. In a grid connected system, you can sell off excess electricity to companies.

In an off grid hydro system, electricity can be supplied directly to the devices powered or through a battery bank and inverter set up. A back up power system, such as a generator may be needed to compensate for seasonal variations in water flow.

Costs and savings
Hydro costs are very specific to the installation site and are related to energy output. For low head systems (i.e. an existing pond or weir), costs may be in the region of £4,000 per kW installed up to about 10kW and would drop per kW for larger schemes.

For medium heads, there is a fixed cost of about £10,000 and then about £2,500 per kW up to around 10kW - so a typical 5kW domestic scheme might cost in the region of £20,000-£25,000. Small scale hydro schemes are very reliable so maintenance costs of reasonable.

Where can I find out more about installation?
You can also find details of installers in our UK directory by clicking the button below. They will also be able to inform you of any available grants.

source: Energy Savings Trust