On Thu, 14 Jun 2007, Patrick Giagnocavo wrote: > Vegetable oil can degrade much faster than diesel. > > What you really want is a large pond at the top of a hill, and another > large pond at the bottom of the same hill. > > When utility prices are low, pump the water to the upper pond. When > power is needed, have your installed hydropower setup allow water to > flow through the turbine from the upper pond to the lower pond. > > In a city, a very large tank located at the top of the building and an > equally large one in the bottom with a pipe between the two, should > suffice. Remember that the "head" or height difference is a large > factor in determining how much power a hydro setup can generate. I just wanted to give a little bit more perspective on above: 1 liter of diesel fuel contains approx 10000WH.
1 liter of water pumped 100 meters up has a potential energy of .272WH It takes a *lot* of water to provide a measurable difference for a datacenter of any significant size... -alex