Wind up power such as the ribbon springs used in clocks for instance. Instead of concentrating on one spring that basically turns one shaft, stack several springs together wound up tight on one shaft and release the springs consecutively. As soon and one spring winds down, the next spring's energy is released and so on down the line. Winding the springs back up could be done the same way or not. Wind them all at the same time with the single shaft. Let's use some worm drive gear combination. Worm drive has a lot of power and can be safer because if you let go the worm drive won't release and go backwards.
I picture a ribbon spring in a cylindrical, disk shaped container stacked on or next to another like records in a jute box. With a standard size(manageable size) it can be used as a mechanical battery. Double the power by releasing 2 at the same time. Windup revisited.
I envision something like that being used in micro-windpower or hydropower where in times of high torque a series of springs are tensioned where as they could be released in times of no wind or drought. With a simple clutch, if full tension was achieved, the system would freewheel, so yes, your idea could easily be designed.
When I was a safety coordinator for a major railroad, one issue I often saw was workers who failed to recognize the amount of stored energy in a simple spring. We often discussed not only locking and tagging out power systems like hydraulic, electrical supplies, etc; but also springs! They have incredible stored energy potential. Coupled to the amazing physics of a planetary geared system, your idea has merit!
I often see micro hydropower applications wired to electrical heating elements to offset over-generation during low use power applications. I often thought a better use would be to use that over-power situation to power a pump that pumps water back up the hill/dam so that water could be stored and later released during peak power times and/or drought situations instead of wasting the power as mere heat. This is done on a huge scale in CT where a nuclear power plant, during times in the middle of the night when power from its generators are not needed, divert power from the grid, to massive pumps that pump water from a reservoir, up a mountain to another reservoir. During high demands for power, water is released through penstocks to water turbines providing additional power to the grid in a very controlled way. Then that night; yep water is again pumped back up the mountain! It is just an example of ways to store potential energy.
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