Elevators in skyscrapers could be used to generate electricity

Shawn Knight

Posts: 14,318   +162
Staff member
In brief: Researchers from the International Institute for Applied Systems Analysis (IIASA) have conceived a gravity-based system that would use elevators in high-rise buildings to generate and store electricity.

The system, dubbed Lift Energy Storage Technology (LEST), would rely on elevators already installed in existing buildings. When not being used to transport people, autonomous trailer devices would load / unload wet sand containers or other high-density materials into elevators and transport them between the bottom and top floors. Regenerative braking systems on the elevators, which are most effective when carrying a heavy load, would generate electricity that could be stored on site and used as needed.

Researchers estimate that there are more than 18 million elevators in operation around the world, and many of them sit idle for a significant amount of time.

Lead author Julian Hunt said the idea came to him after moving into an apartment on the 14th floor of a building and spending a lot of time riding the elevator up and down.

Several hurdles stand in the way of real-world use. For starters, the ceiling bearing capacity of existing buildings – that is, how much weight the ceiling can support without collapsing – would have to be taken into consideration. Operators would also need to set aside room at the top and bottom of buildings to store the heavy weights, and consider how much additional wear and tear the system would put on existing elevator infrastructure.

The full study has been published in the journal Energy for those interested in delving deeper.

Image credit: Sean Pollock, Kelly L

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yRaz

Posts: 4,604   +5,530
Most elevators, if not all, use electronic motors. A motor run in reverse becomes a generator. There is no reason why we can't apply the same concepts of regenerative breaking to elevators. It'd probably be very cheap to retrofitt existing elevators.

We wouldn't need to remove cabling, and for people who are afraid of that kind of thing.

1) cables can break and the spooling mechanism attached to it.

2) elevators have multiple failsafes in place for failure. It's almost identical to the ratcheting mechanism on Rollercoasters.
 

stewi0001

Posts: 2,774   +2,545
2) elevators have multiple failsafes in place for failure. It's almost identical to the ratcheting mechanism on Rollercoasters.
If you really want to get crazy, you can mimic the fail-safes in the "Tower of Terror" XD


I'm not sure if this would be really worth it. Main thing I wonder about is the durability of the elevators. I'm not worried about them plummeting but becoming more frequently out of service.
 

Adhmuz

Posts: 2,261   +1,088
This made sense when I thought of it as; when an elevator car is loaded full of occupants on the top floor and needs to be brought to the ground floor you could generate some electricity there, sure, why not.

However to start loading them to capacity to bring weight to the top floor to then store that as potential energy which would not be fully recovered when brought back down seems like a bad idea. You'll be putting needless wear and tear on all the components of the elevator, need to allocate floor space to store all that weight and engineer the building to accommodate the added weight load as well. All in the interest of storing some energy for peak hours of the day?

If tall buildings are to be used to store energy it shouldn't be in the form of sand bags and elevators... Use a fluid, pump it up and store it in the floor cavities, then when peak demand occurs it can be used instantly and not encumber the use of the elevators.
 

Bullwinkle M

Posts: 737   +636
Save the elevators

If you want a massive amount of FREE energy without lifting wet sand to the top floors of skyscrapers, just find a way to guide a mile wide asteroid into Manhatten

An asteroid traveling at 30,000 mph would give you more free energy than you could ever hope to use in your short lifetime

:)
 

seeprime

Posts: 681   +893
It is impossible to achieve greater than 100% efficiency when converting energy from 1 form to another. In the real world, efficiency does not reach 100%. It will take more energy to move the weight on/off/up than could possibly be generated.
Maybe the heat generated when braking could be turned into usable energy. If it's cheap enough, it'll happen.
 

Tantor

Posts: 349   +629
The article is a misnomer. The original paper is about using building elevator systems to STORE energy. It's called Lift Energy Storage Technology, and addresses the problems of large scale electricity storage. It's not about generating energy.
 

Godel

Posts: 305   +192
It is impossible to achieve greater than 100% efficiency when converting energy from 1 form to another. In the real world, efficiency does not reach 100%. It will take more energy to move the weight on/off/up than could possibly be generated.

It's not about generating energy, it's a method of off-peak energy storage which can be called upon for use in peak hours.
 
The article is a misnomer. The original paper is about using building elevator systems to STORE energy. It's called Lift Energy Storage Technology, and addresses the problems of large scale electricity storage. It's not about generating energy.
Now it makes sense
 

captaincranky

Posts: 18,816   +7,737
Several hurdles stand in the way of real-world use. For starters, the ceiling bearing capacity of existing buildings – that is, how much weight the ceiling can support without collapsing – would have to be taken into consideration. Operators would also need to set aside room at the top and bottom of buildings to store the heavy weights, and consider how much additional wear and tear the system would put on existing elevator infrastructure.
You realize that this is pure bullsh!t, right? It's just this years incarnation of the long sought after "perpetual motion machine".
 

Endymio

Posts: 1,794   +1,835
The article is a misnomer. The original paper is about using building elevator systems to STORE energy. It's called Lift Energy Storage Technology, and addresses the problems of large scale electricity storage. It's not about generating energy.
You beat me to the punch. Most people fail to realize that the problems of distributing and storing 'green' energy far outweigh those of actually generating it.

This just seems like a failed business plan, though. The amount of revenue generated will be small, and given the startup costs and the potential for additional elevator maintenance downtime during normal business hours - times when losing even a few minutes means disgruntled corporate tenants -- I don't see many of these being approved.
 

OortCloud

Posts: 792   +775
I'm relieved to read the comments and see lots of people saying what I was thinking. For a minute I thought my entire understanding of the basics of physics were wrong and that magic elevators could somehow create more energy than they used just by going up and down.
 

Crinkles

Posts: 247   +220
Yeah and the largest obstacle in the way to avoiding total commercial fauilure is the US patent office.




...and fissicks
 

Inthenstus

Posts: 124   +172
It is impossible to achieve greater than 100% efficiency when converting energy from 1 form to another. In the real world, efficiency does not reach 100%. It will take more energy to move the weight on/off/up than could possibly be generated.

True, but it may not matter. They could move the weights to the top overnight, and lower them during the day. This is similar to some hydroelectric plants pumping water uphill at night and lowering during peak hours (the day).
 

Hollow

Posts: 55   +55
It is impossible to achieve greater than 100% efficiency when converting energy from 1 form to another. In the real world, efficiency does not reach 100%. It will take more energy to move the weight on/off/up than could possibly be generated.

Yep, this infinite energy concept sounds strange to me, the only way it would work is if more people used stairs to go up and elevators to go down. Would be even more effective in an US country because people are more heavy but it probably wouldn't happen because they are heavy for a reason.
 

mbk34

Posts: 354   +255
I don't think the idea is practical. You could only use the elevators while the building is not being used (say 10pm to 6am). Half that time you'll be loading the weights in to store energy and half the time you'll be unloading the weights to generate energy. That matters because you can only store green energy between 10pm and 2am before you have to start unloading again. You're then forced to release the stored energy back onto the grid between 2am and 6pm which isn't when you want that energy.
 

Avro Arrow

Posts: 2,574   +3,139
TechSpot Elite
It is impossible to achieve greater than 100% efficiency when converting energy from 1 form to another. In the real world, efficiency does not reach 100%. It will take more energy to move the weight on/off/up than could possibly be generated.
Getting greater than 100% efficiency is impossible, that's true. However, electric heaters are considered to be 100% efficient:
"Electric heaters are all considered to be 100% efficient, because they turn all the electricity they use into heat, but this does not mean they are cheap to run. To calculate the running cost you need to look at the power rating of the heater, shown in kilowatts (kW)."
I didn't say this to disagree because in every other situation, you're right. I just thought that I'd throw that little tidbit of knowledge in there because it's actually pretty awesome when you think about it. There is something we do that is 100% energy-efficient. We actually did something right! :laughing:
 

passwordistaco

Posts: 339   +789
Getting greater than 100% efficiency is impossible, that's true. However, electric heaters are considered to be 100% efficient:
"Electric heaters are all considered to be 100% efficient, because they turn all the electricity they use into heat, but this does not mean they are cheap to run. To calculate the running cost you need to look at the power rating of the heater, shown in kilowatts (kW)."
I didn't say this to disagree because in every other situation, you're right. I just thought that I'd throw that little tidbit of knowledge in there because it's actually pretty awesome when you think about it. There is something we do that is 100% energy-efficient. We actually did something right! :laughing:
Usually heat is the waste that cuts into efficiency. I guess it's possible to reach 100% "waste" 😁
 

Avro Arrow

Posts: 2,574   +3,139
TechSpot Elite
Usually heat is the waste that cuts into efficiency. I guess it's possible to reach 100% "waste" 😁
Yup. We did the "One man's garbage is another man's gold" thing with it. Now if we could only do that with everything else.

I can't wait for the day when we finally master the art of fusion power. It will be the most transformative thing to society since the invention of the electric grid.
 

Endymio

Posts: 1,794   +1,835
I can't wait for the day when we finally master the art of fusion power. It will be the most transformative thing to society since the invention of the electric grid.
Environmentalists will shut it down just as fast as they did nuclear power. Remember that, however close we are to economically viable fusion power, we need the much-more-difficult to master aneutronic fusion in order to eliminate any and all radiation. And even when we do that, it'll be attacked for some other reason.

As famed environmentalist Paul Ehrlich said: "giving society cheap, abundant energy is be the moral equivalent of giving an ***** child a machine gun." Many other environmentalists have expressed similar points of view.