Run-of-River, Marine and Tidal Streams

Power Generation

From the efficiency studies performed in practice with the sensing and acquisition of real measurements, it was proved that for the more efficient stream accelerator model (model A1) named as hydroreactor stream accelerator, the flow velocity Vt through the channel narrower zone, is in absence of any flow constraints about 40% higher than velocity Vc of outside free stream. 

It was also verified that, in the absence of any flow constraints there is a certain constancy on the ratio Vt/Vc between the flow velocity Vt and the stream velocity Vc, for typical stream velocity values, meaning that hydroreactor stream accelerators present almost steady efficiency values in the range of typical stream velocities. 

This means that the loading (energy per liquid mass) of the flow in the channel narrower zone is about 2 times higher than the outside free stream loading and the power density in the channel narrower zone about 2,75 times higher than the outside free stream power density. It means also that the hydroreactor stream accelerator introduces a significant net head +DH of about 200 mm for a stream of 2 m/s (4 knots), 300 mm for a stream of 2,5 m/s (5 knots) and 400 mm for a stream of 3 m/s (6 knots). 

The following graphic shows the variation of introduced net head +DH and of the available power P, with the stream velocity Vc, for Hydroreactor stream accelerators with channel narrower diameters of 1m, 1.5m and 2m, assuming a ratio Vt/Vc between the flow velocity Vt and the stream velocity Vc in the absence of any flow constraints with a constant value equal to 140%.  

The following table resumes the expected nominal power of hydroreactor stream accelerators with channel narrower diameters of 1m, 1.5m or 2 m rated for stream velocities of 4 knots (2m/s), 5 knots (2,5m/s) and 6 knots (3m/s).

Narrower channel diameter

Border external surface maximum diameter 

Duct Length Nominal Power at 4 knots (2m/s) stream Nominal Power at 5 knots (2,5m/s) stream Nominal Power at 6 knots (3m/s) stream
1 m 4,6 m 7 m 8,5 kW 16 kW 29 kW
1,5 m 6,75 m 10,5 m 19 kW 37 kW 65 kW
2 m 9 m 14 m 34 kW 67 kW 115 kW

This technology has great potential for the conversion of the kinetic energy from streams, because hydroreactor stream accelerators have the same effect of a very small fall/dam in addition to the stream strength. Hydroreactor stream accelerators introduce a significant net head generating a flow with much higher loading than the stream, what will promote extraction of power from streams on a higher number places/sites.

Tidal streams present a constant form of energy because of gravity effect of the moon on the rotational motion of the Earth, generating the same amount of energy with much less power than in wind and solar systems.