What is a hydrokinetic power plant?
A hydrokinetic power plant generates electricity by letting the natural flow of a river or the sea drive a turbine. The turbine sits freely in the current, rather like a wind turbine under water. Unlike conventional hydropower there is no dam and no reservoir. At sea this is usually called tidal stream energy; in Dutch it is a stromend water centrale.
Output depends on the speed and volume of the water. Marine turbines are placed where the tides create strong currents. A well-known example is the floating O2 by Orbital Marine Power: a 2 MW turbine that has been exporting power to the grid since 2021 at the Fall of Warness test site of the European Marine Energy Centre (EMEC) in Orkney, Scotland.
How it differs
- Tidal power station: uses the tides, either with a barrage and basin (height difference) or with free-standing turbines in the tidal stream. The second type is a hydrokinetic plant at sea, which is why the terms overlap.
- Wave power plant: captures the up-and-down motion of waves, not the current.
- Pumped storage power station: relies on reservoirs and a head of water.
Application
- Only with a strong, steady flow. No current, no power. Rivers whose flow swings with rain, drought or snowmelt are poorly suited.
- For homeowners, think small. A micro water wheel or small turbine in a stream on your land usually produces little, because the flow is modest. Have an installer estimate the output before buying anything.
- Sort out consent first. Placing anything in a watercourse normally needs consent from the environmental regulator, such as the Environment Agency in England. In the Netherlands the water board (waterschap) decides.
- Look at existing sites. An old mill wheel or an existing weir is often a more sensible location than a new structure, but it still needs consent.
Common mistake: assuming a small water wheel at the bottom of the garden needs no permission because it is “only small”. Any installation in a watercourse falls under the regulator’s rules.
Related terms
- Tidal power station
- Wave power plant
- Pumped storage power station
- Windmill
- Weir
Want to know more about building terms? Visit our knowledge base at fredsdiyplans.com.