Output of less than 50kW: So what qualifies as a
micro-generator? In the UK the term is used to describe generators with
an output of less than 50 kilowatts, but in other countries the term
small-scale can apply to installations running into the megawatt range.
Archimedes screw becomes generator: Even the Archimedes screw
has been transformed into a micro-generator, thanks to Ritz-Atro, a
company based in Nuremberg, Germany. Its devices are capable of
generating anything from 1 kilowatt upwards, from flows a of just 70
litres per second. The company has said they could be used in
situations where the flow is too low for other micro-generators, such
as small weirs or the waste outflows from small industrial plants. Two
small screw generators have been installed in outflow pipes at water
treatment plants near Tubingen in Germany, for instance.
New Scientist, 21/1/2006, p. 37