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Old 12-19-2009, 10:15 AM
cragger cragger is offline
 
Join Date: Aug 2007
Posts: 632
Default Re: The Next Rare Earth Crisis

Jeff,

I also think storage using water as a potential energy source is a good idea as indicated in my comment below. There is a question of how small this scales efficiently though. There are a couple aspects of that - technical and economic. Technically, the amount of energy depends on the height and larger installations typically operate more efficiently than small ones for other factors. Probably hydraulic flow issues related to the diameter of the pipes, etc. if nothing else.

Economically, you come up against the question of dollars per joule of storage per year over the life cycle of the system. At a small scale the cost of the installation may drive toward other storage methods, and water as potential energy may be better suited for large (e.g. dams) or medium scale, community applications. Many towns have water systems, using reserviors or water towers. Combining the provision of water with operation of an energy store might mean only that the system should use the highest practical storage rather than what is probably the lowest storage (in the case of water towers) that maintains the flow. Addition of a second tank or catchment below the tower or reservoir would allow recycling of water beyond the supply flow to make the energy storage function work better of course.

Just what scale is efficient and how it compares to other energy stores would make a nice little study. Ideally one that somebody could cage a way to get paid to do. Maybe you or someone else here works in a location that hires coop students or has other contact with an academic community and it would work as a student project.

Last edited by cragger; 12-19-2009 at 10:19 AM.. Reason: an added thought
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