Following on from this and Adam's comments I think that every hydro generator would have some form of rpm governor fitted.Catweazle wrote:Does anyone make a load sensing device that can open a sluice gate / valve "on demand" ? It could be linked to hydro RPM.
That would make the mill pond approach more useable.
Not sure what type of hydro is present at Lammas but 27 kW is a pretty hefty off-grid system. Given that a rule of thumb for hydro is you get 7kW generated from 1 cubic metre of water falling one metre in one second this plant will be a run of river scheme on a fairly big river or have a few hundred litres of water falling a hundred metres or so. If low head they will need a reasonably large river and slow rpm (maybe like a water mill site with kaplan turbine with wicket gates) and if a high head will have a mountain stream and a jet type system at high rpm (pelton wheel turbine with valve). Either way they will need the device to vary the amount of water at the bottom of the 'hill' next to the turbine otherwise very interesting things will happen.
Not my expertise but I think that there will be two types of control on this system at the bare minimum.
1) Speed control by controlling the amount of water through wicket gates if it is a low head or valve if high head. This will either be set to speed of turbine or frequency of voltage output. They could also even out sudden changes on speed due to someone switching on a vacuum cleaner by having a large flywheel or even the natural inertia of the generator (this number is even quoted on a lot of generator datasheets).
So very unlikely to have some kind of 'dumping system' for excess load eg hot water immersion heater much more likely to have a speed control so when very little load just have the system freewheeling.
2) Voltage control to stop voltage dipping controlled by excitation of generator. I am presuming that a relatively small generator as 27kW will still have voltage control.
Other than that they could use solar hot water heating and use each household solar for 12 Volt equipment and maybe wood for cooking (mind those PM 2.5 values though) - a lot of people in my town in Australia have wood burners and the pollution from the neighbours fire is unbelieveable at times - I have to have my windows closed and sealed.
All in all if anyone in the UK is lucky enough to have geography that allows for a 27kW hydro system they should do it in this day and age. If the council, , Water Company, National Rivers Authority, Council, various NIMBY organisations and Greens allow it of course.