Isn't it like electrical power? We can have a large flow at a slow rate OR a small flow at a fast rate to develop the same amount of power, using suitable equipment in each case.

In principle yes. Pelton wheels (and there are a number of variations on the same basic design) are indeed pretty efficient with high heads of water. The speed of the water is ultimately driven by the head of water available (less resistance of whatever pipe or channel contains it) - so the maximum available power is still dependent on the head, and weight of water flowing every second. Power = m x g x h (m = mass of water (in kg, or litres if you prefer), g = force due to gravity = 9.8N/kg, h=height difference in metres.) Answer is in Watts (not kW), In small systems reckon on about 50% in efficiency losses.

   - Andy.

Isn't it like electrical power? We can have a large flow at a slow rate OR a small flow at a fast rate to develop the same amount of power, using suitable equipment in each case.

In principle yes. Pelton wheels (and there are a number of variations on the same basic design) are indeed pretty efficient with high heads of water. The speed of the water is ultimately driven by the head of water available (less resistance of whatever pipe or channel contains it) - so the maximum available power is still dependent on the head, and weight of water flowing every second. Power = m x g x h (m = mass of water (in kg, or litres if you prefer), g = force due to gravity = 9.8N/kg, h=height difference in metres.) Answer is in Watts (not kW), In small systems reckon on about 50% in efficiency losses.

   - Andy.