KESS (Kinetic Energy Storage Systems)

Beacon Power, Amber Kinetics, Energiestro, etc. All of these companies make(or made) kinetic energy storage systems that implement flywheels. Most of these are in a vacuum and use very good bearings and electromagnetic stability controls. Efficiencies are 85-90% and they last for decades with minimal maintenance. I worked on installing some of these at a data center in California about a decade ago and they were ridiculously expensive. I just don't see how spinning a weight can be so much more expensive than batteries, not to mention better for the environment. It seems like a 40kWh residential system installed for $30-40k should be very doable and it would eat Tesla's lunch, especially when you consider the longevity. Have you guys ever seen these or heard of other companies in this field?

I can remember 30 years ago, I had access to the rooms around the university's mainframe computer, and there was a large room lined wall to wall with deep-cycle batteries.  They in turn powered an electric motor/generator combination that incorporated a massive concrete flywheel about 5' in diameter.  The concept was that fluctuations in the incoming grid-power were dampened out by the rotation of the very heavy flywheel, which guarrantied very clean power to the mainframe.

Daniel Richardson wrote:Beacon Power, Amber Kinetics, Energiestro, etc. All of these companies make(or made) kinetic energy storage systems that implement flywheels. Most of these are in a vacuum and use very good bearings and electromagnetic stability controls. Efficiencies are 85-90% and they last for decades with minimal maintenance. I worked on installing some of these at a data center in California about a decade ago and they were ridiculously expensive. I just don't see how spinning a weight can be so much more expensive than batteries, not to mention better for the environment. It seems like a 40kWh residential system installed for $30-40k should be very doable and it would eat Tesla's lunch, especially when you consider the longevity. Have you guys ever seen these or heard of other companies in this field?

I would be interested to see what people come up with. Tesla is a high end product basic lithium would not cost you 40000 for 40 Kw Hrs. No fuss no muss forget about it for 10 years. That's the promise anyways. It pulls a lot of wind out of alternatives sails having an off the shelf option that keeps getting cheaper.

Funny enough this popped into my feed.
https://www.ablogtowatch.com/switzerlands-springstation-is-a-sustainable-electricity-power-plant-run-by-you/

Springs not flywheels byaybe more doable.

Just checked the Tesla Powerwall prices and 40kWh is around $25k, before tax and installation. After taxes, hidden fees, and install it would probably be pushing $40k. I guess the beauty of KESS is that they supposedly can last much longer and maybe only need to have bearings and simple circuit boards replaced after 30 years. Very few exotic or nasty chemicals involved either and I imagine Kess would run in the arctic just as well as the tropics.

This book looks promising:
https://www.amazon.com/Kinetic-Energy-Storage-Practice-Advanced-ebook/dp/B00IMBVXX2

Anyone know of any other good sources of info, human or otherwise on the subject?

The problem with this method for a vehicle is the enormous angular momentum the device has.
Turning a corner would be like trying to rotate a gyroscope. The combined angular momentum vector would flip the vehicle on it's side, back or front depending on which way you tried to turn.

I imagine the weight considerations might make the installation cost substantially higher then the cost of batteries for a home storage device.

The floor on which it rest might need to be reinforced.

It would likely be almost impossible to install one holding a "charge", again because of the angular momentum.

But I imagine there are situations where it's feasible and more cost effective than batteries.

If the flywheel can be mounted with its axis vertical, there is little or no gyroscopic effect when the vehicle turns. A significant gyroscopic effect already exists in vehicles due to the flywheel attached to the horizontal crankshaft of the engine.

I just don't see how spinning a weight can be so much more expensive than batteries

The problem is how fast the weight needs to spin in order to store any meaningful power. Chemical energy is just very dense compared to basically all forms of mechanical energy storage. Giant flywheels are a neat idea, but they have to be engineered very well or else they become a serious safety concern. Can you imagine what would happen if 40 kwh of spinning steel in your garage was to suddenly dump that energy? Kaboom.

As for costs, LiFePO4 batteries at present you can buy cells and a BMS for around 225$/kwh. My understanding is that the auto companies are getting prices closer to 100$/kwh for batteries. They should easily last for a decade or two, contain no toxic metals, weigh like 15lbs/kwh, and while they are not really recycled at present I suspect that in a few years time they will basically all be reclaimed and either reused/refurbished or recycled.

I just do not see batteries falling out of favor for small-scale power storage, and the technology keeps getting better. Energy density might be approaching its limit, but I think there is still a lot of room for things like cycle life to improve.

Dc Stewart wrote:If the flywheel can be mounted with its axis vertical, there is little or no gyroscopic effect when the vehicle turns. A significant gyroscopic effect already exists in vehicles due to the flywheel attached to the horizontal crankshaft of the engine.

A crankshafts inertial energy is only what's necessary to transfer the energy to the wheels. A fly wheel power supply has to have enough to do that for a few hours.
mounted on the vertical axis would work on a flat surface but he slight rotation of going up or down a hill might lift one side of the vehicle right off the pavement.
I suppose you could mount the fly wheel with a gimbal mount and eliminate any such problems entirely.

I'm not at all opposed to the fly-wheel idea. In fact I am considering a magnetic fly wheel in space for a hypothetical method of extracting orbital energy from the moon.
I just posted the idea today.

I know it sounds crazy but NASA is already extracting orbital energy to power space probes several hundred AUs away.
Wouldn't it be nice if they could just bring that energy back to earth?