Creative Energy Storage Displays

[TheTalkingMule]

I live in a Philadelphia neighborhood with lots of foot traffic on the weekends coming in from all around. I'd like to develop an artistically creative non-battery energy storage system for the front of my rowhome to highlight the value of things like Powerwalls and pumped hydro storage. I'm set back 6-10ft from the rest of the houses on the block, so there's room for mechanicals.

My 6.6kW solar array is kicking 70%+ of my production back to the grid(fine since I have net metering), but I think it'd be fun to integrate an exterior mounted Powerwall and then another mechanical storage device that would charge the Powerwall. Something like a geared pulley that lifted 300lbs up the face of my house(via solar at peak), then slowly lowered it back down to charge my Powerwall. Sounds foolish and wasteful, but we really need to wrap people's heads around solar and storage here.

A) Is that even possible to have something like a small generator turbine charge a Powerwall?

B) How absurd would the losses be?

C) If I were willing to thumb my nose at the utility, could I skip the Powerwall altogether and just let the above rig act as storage? Basically, could I intercept charge from my panels and replace it with charge from a turbine while still getting net metering credits?

 

[miimura]

I think the main point is how absurdly small the mechanical energy stored in your scenario above is.
If you lift 300# about 36 feet in the air you don't even have enough kinetic energy to charge half of one 18650 battery cell. That doesn't even count mechanical to electrical conversion losses.

 

[TheTalkingMule]

A cow then perhaps? I'm open to ideas!

A series of inflatable bladders?

Molten salt?

 

[mspohr]

A cow then perhaps? I'm open to ideas!

A series of inflatable bladders?

Molten salt?

Hard to raise the cow in the air very far. It would probably get upset. It does have more mass but it also generates methane.
Use electricity to generate H2 and O2. Mix them together in a plastic bag with an ignitor. (Don't do this near the cow.)

 

[RubberToe]

Easy Peasy, a smaller version of this should do quite nicely...

 

[RubberToe]

I was pretty surprised by @miimura calculation. I would have thought it would have been more. I do remember hearing that each 18650 battery could move a Model 3 200 feet. So a 300 pound weight descending 30 feet has about the same stored energy. That kind of makes sense...

I like the general idea though. Put up a small LED display showing energy being used to move the weight up, and then how much energy is being generated on the way down. Use the mechanical energy to power the LED display. You could also pdisplay additional information like how much energy is required to do various things, like lighting a 100-watt light bulb for an hour. And correlate that back to how much energy is stored in the mechanical device. Then let people know how much energy is required to move a vehicle a certain distance, also relative to the power stored in the mechanical device. A Raspberry Pi computer ($35) could do all the required calculations and drive the display. Kind of like a like science museum exhibit for passing people to ponder. Living STEM lesson in action...

Most people don't have a clue how much energy is required to move a vehicle around. They just put gas in their car and don't give it a seconds worth of thought. I got interested in that a few years ago based on an article I read. I calculated that our house in the South Bay (mild climate) used 10KWh of electricity per day. My condo in Pasadena (all electric) uses 15KWh per day (prior to EV charger install). My 2000 Honda Insight used 25KWh per day (equivalent) for my work commute. And Mrs. Toe's Honda Element used 50 KWh per day (equivalent) for her work commute. The numbers were easy to remember, cause the Insight used as much as both residences, and the Element used as much as all 3 combined. That was a real eye opener.

With a Kia Soul EV and a Model 3, our equivalent vehicle energy usage dropped from 75KWh per day down to 15KWh. Even at $0.26 per KWh, daily cost of $3.90 beats two gallons of gas at $4.09 each for $8.18.

RT

 

[ItsNotAboutTheMoney]

A cow then perhaps? I'm open to ideas!

A series of inflatable bladders?

Molten salt?

Model X?