I've posted about hydroelectric power in the Lake District but I've never seen one being built.
The water is set to fall from the stream near Hayeswater at 400m to a level of 200m. The pipe will be buried under the road. The new power station will be on the site shown below.
That's right next to an old mine water wheel. It used the kinetic energy from the gill to power pumps to drain water from a nearby mine. http://www.mindat.org/loc-4753.html The new works therefore sit in an old industrial area with both mining and an old reservoir.
At 250kW, we were trying to work out how many houses it would power. Maximum consumption might be oven and shower at 8kW each. At full power, that would be only 15 houses. Glenridding Hydro is 500kW and claims to power 300 houses on average, so average power consumption for house would be 1.7kW. This seems reasonable but the National Grid is needed to cope with the fluctuations in usage. Suppose that the water falls without disipative losses and all mgh of gravitational potential energy turns into kinetic energy. The water would be going at square root of 2x9.81x200 = 63 metres per second. If average power = Fv and we assume that the generator stops the water dead so that F=rate of change of momentum = v x rate of mass, then average power = v squared x rate of mass. Mass flow rate for the water would be 250000/63 squared = 63 kg per second.
