Electrical percentage loss in motor to generator

"Drive a motor to store "

"Generator to produce as much electrical power as possible when required"

"Mechanical energy and back again"

"A direct shaft for thee purposes of the percentage loss"

I think you need to go back to college to understand the basics .

It seemed to make sense to me when I wrote it. Try this:- Intermittent renewable electricity is used to drive a motor. The motor winds up a spring, this spring is used to store the energy until needed. Electrical energy is produced when wanted through a generator driven by the spring. All that I need to know is a percentage the amount of wasted energy through transferring the electrical energy into mechanical energy and back to electrical energy. This is to replace batteries and enable the intermittent wind or wave power to be available when wanted. At present the cost of "batteries", high-tech or otherwise are costly. These receive electrical power and produce the same. My scheme is amazingly simple and cheap but what are the losses compared to the renewable energy being used to store mechanically directly from the rotating turbine and generating from here when needed?

Each energy conversion step (like electrical to mechanical) is lossy as you surmised. LARGE motors and generators can have efficiencies in the 90% range, but smaller motors and generators should be considered to be around 70% (each way). That's about 50% round trip.

This will not be your biggest problem. Getting sufficient energy stored in a reasonable volume at a reasonable cost is the problem MANY people are working hard to solve. It would be nice if you had the answer. Since many here are grounded in reality and this is an engineering forum, you will need to present hard verifiable evidence to convince anyone that your idea is the solution.

Don't let that stop you from trying!

Nearly impossible to determine. The problem with mechanical energy storage is the diminishing nature of the energy transfer. So with springs for example, the mechanical energy stored in the spring starts at one value, then as soon as some is released, the RATE at which the rest is released immediately begins to diminish, not just the total stored amount. So the conversion from that stored energy back to electrical energy is going to be dynamically affected by the potential energy in the diminishing spring force. The same holds true for storing it in the first place; the amount of energy it takes to wind the spring increases as the spring is wound. So the conversion rate is extremely dynamic as well.

Technically, the same is true for stored water behind a dam. The reason we don't care too much is A) the cost of getting the water behind the dam is virtually free (solar energy) and B) to total potential energy stored is so massively higher than what we can utilize that the dynamism becomes less and less meaningful. But with a mechanical spring, the potential stored energy is directly related to the cost of making the spring!

Thank you for the feedback. The spring is not relevant as the stored force is constant, this was merely an example of putting the energy in and getting it out again. My concern in the question is that my scheme is in competition with stored hydro where electric power us used to feed the store. If the storage can be achieved at the point of original capture, at the base of the wind turbine, the feed can be mechanical, thus minimising any loss, it can additionally accept energy from light winds that would not be sufficient to produce usable power. With variable gearing any wind speed could be utilised to add to the store. My original question was to ascertain what percentage of the initial energy caught could be utilised after having been stored in comparison to existing storage systems. It seems that from the previous answer there could be as much as a 50% saving by feeding into store mechanically at the point of capture. The following is a teaser to see if you can work out how the device works:- A simple inexpensive way to store vast amount of energy has been devised that:- - Utilises a waste product. - Does not involve vast civil engineering construction. - Is not seen. - Can receive and supply at the same time. - Can be added to as required whilst still in use. - Can be as vast or small as required. - Costs considerably less than any other electrical storage system. - Can be stored for minutes or months. - What goes into store can be called off with minimum loss – at times it can in fact supply more than what was fed in. - Simple concept. - Tip: Think of a grandfather clock upside down at sea. If this looks attractive or even impossible have shot at explaining it. I have not and do not intend to take a patent I have worked on this for the past 20 years and although I took a patent 18 years ago on a similar scheme that was investigated it was found to be uneconomic when investigated by government hired consultants. It has since been considerably simplified and tackled for another purpose. Energy storage.

I'll bite and assume this is your tidal energy idea or something related.

There are good reasons, OTHER than big-oil conspiracy and vacuous politicians, that ocean tidal energy is not more frequently used.

Ocean waves, tides, currents, and temperature variations can all be tapped for energy. These ideas have been around for a long time and are not really new. Basic math, physics and cost dictate whether or not this energy can be economically captured and put to use. Unfortunately, that pesky math-physics-cost thing keeps getting in the way of a lot of wishful ideas.

If you can back your wonderful claims with solid and verifiable numbers, people WILL LISTEN and take you seriously. Otherwise, your sales/idea pitch sounds like a million other dead end schemes. If you are NOT looking for funding or selling "snake oil", then you are one of the few honest dreamers. Eventually, you will learn WHY your idea in its current incarnation is not hugely successful. The sooner you learn to evaluate new ideas with impartial scientific and economic criteria, the sooner you may actually discover a REAL solution to the worlds energy problems. Good luck.