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#26 2019-11-28 08:07:15

tahanson43206
Moderator
Registered: 2018-04-27
Posts: 3,486

Re: Gravity Energy Storage

For Calliban re #22 and earlier ...

Thank you for considering the topic (of gravity storage) further, and for adding additional examples of creative design from the historical record. 

In an earlier post (in this topic or another) you reported the invention of a means of compressing gas (air) in a liquid (water) by allowing bubbles to flow down a column of moving water, as into a mine for tools and breathing air.  I am looking forward to finding a block of time to follow the link you provided, to try to understand the concept better, and the specifics of how it was used.

We appear to have the potential for a robust design competition to develop solid plans for various energy storage systems which could be deployed on Mars, or perhaps other locations in the Solar system.

You and SpaceNut have both identified real or imagined weaknesses of gravity storage systems, and that kind of feedback should lead to improved designs which would ultimately find testing in the real world.

However, gravity storage has more than one branch, and there are competing storage proposals, such as batteries, superconductors and even chemical state change for long term storage.

I would like to see a (somewhat) organized competition between the design concepts.

All require physical components, so the benefit of one design over another will depend upon the availability of particular materials and the amount of energy required to shape them into the form needed.

All will require maintenance, and the details of where failure will occur and how it will be addressed will lead to understanding of relative strengths and weaknesses of particular designs

The use of water for gravity storage on Earth makes a great deal of sense where weather patterns deliver copious quantities of water for such use.

The absence of water in many locations on Earth would encourage use of available material (eg, sand) for gravity energy storage.

In the case of Mars, it seems (to me at least) ambitious to imagine a water based energy storage solution.

Some confusion exists (at least as I read the current topic) because the starting point was the idea of a cable storage system found by SpaceNut.

I have been moving steadily away from the original suspension cable system to an alternative based upon a hybrid of cable to provide flexible anchoring for mass (eg, carts filled with sand) running on a solid monorail such as may be seen in many installations on Earth for short distance transportation.

For further clarification, I am thinking of a monorail BELOW the moving components, NOT a suspended monorail.

The idea there is to take advantage of the natural stability and long life offered by the planetary terrain, and to minimize the number of components or design elements under tension against the gravitation field.

The problem of how to draw power from a cable with carts clamped to it has received some attention here in recent times.  I don't have a solution worked out, and don't like the idea of unclamping carts from the cable to allow the cable to pass over a wheel connected to a generator.

I'm hoping to have the time to explore energy requirements for operating a decent sized steel mill. 

A quick Google search brought up Wikipedia articles about the steel industry, but I did not find reference to heating other than the historical reference to coal.

Another quick search brought up electric arc melting of scrap metal in specialty shops.

That option is more along the lines of what seems appropriate for a serious steel mill operation on Mars.

Louis' methane could certainly be used, so long as whatever process produces the methane also produces the oxygen needed for combustion.

And in any case, Louis' methane will require water for the hydrogen, so that will be needed in abundant quantities.

A gravity storage system that runs up the slope of Mount Olympus could (depending on how the numbers look) provide the concentrated energy needed for a full scale steel manufacturing plant. 

Edit: The challenge of drawing power from a moving cable encumbered with clamped mass carriers might be overcome by a combination of suitable spacing of clamps on the cable, and multiple power take-off positions at the generator station. While this system would require movement of the power take-off wheel, and therefore add to the mechanical complexity of the system, it would/should be fairly straight forward to design and implement.

OK ... a shift of the generator station to the end of the cable run would eliminate the need for the added complexity.

And as SpaceNut pointed out, the clamps for the mass carriers would need to be fitted with pivots, to negotiate the transition from the slope to the roll-out flat section of the track.

And the addition of a lifting motor station at the top of the slope would assist with drawing the mass up the slope, again without need for additional mechanical complexity.  The lifting motor would (presumably) be near the field of solar panels to be harnessed to lift the mass up the slope.

Edit(2): Here is a financial summary of steel making in (about) 2019:
https://www.thebalance.com/steel-production-2340173

(th)

Last edited by tahanson43206 (2019-11-28 10:17:34)

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#27 2019-11-28 12:52:53

Calliban
Member
From: Northern England, UK
Registered: 2019-08-18
Posts: 529

Re: Gravity Energy Storage

Regarding steel making, a good place to start is embodied energy, which includes estimates of energy needed in all activities to produce the material.  In the case of steel, it is dominated by smelting.

https://en.wikipedia.org/wiki/Embodied_energy

Something like 70% of all steel in the EU comes from recycling now, so only a third of steel is virgin steel that requires metal oxide reduction by carbon monoxide.  Modern steel furnaces rely on electric induction for achieving the required temperatures.  On Mars, we would likely do the same.  Direct electric would bring the furnace to temperature, whilst methane, hydrogen, CO, etc. will serve as reducing agents.  That reduces the fuel requirements substantially.

To make 1kg of steel from 70% recycled steel, takes about 20MJ.  For virgin steel, about 30MJ/kg.  That reflects the extra fuel needed to chemically reduce the iron(ii) oxide into pure iron.

On Mars, to produce 10MJ of hydrogen for reducing iron oxide, will take about 15MJ of electricity.  So 1kg of low carbon steel on Mars will cost a minimum of 35MJ.  This energy assumes a scale economy that we may not be able to achieve on Mars (smaller furnaces are less efficient) but it allows a baseline cost for now.

Suppose we need to produce 100 tonnes of steel per day to manufacture a pressure dome.  That is an energy cost of 100,000kg x 35MJ = 3.5million MJ.  That is a continuous power input of 40.5MW – a lot of juice.  The temperature of the refractory lining is about 1200C.  The thermal expansion at those temperatures is so great, that thermal cycles inevitably result in cracking, which damages the lining.  Once you start a blast furnace, you don't want to shut it down unless absolutely necessary.  You need baseload power to make steel, although the power used to make the hydrogen, methane or CO reducing agent, could be variable, at least to a point.

We will need a lot of steel to make any pressurised structure on Mars that isn't underground.  That includes steel pressure struts for things like greenhouses, in which to grow food.  I worked out previously that producing 3000m2 of cropland on Mars (the amount needed for 1 person), would require 36.7tonnes of low carbon steel for pressure resisting frames.
http://newmars.com/forums/viewtopic.php?id=9187&p=2

So, producing enough farmland for one person would require continuous power of 40kW for one year.  Then you have the energy cost of water (1MJ/kg) and heating.  Living on Mars will be an energy hungry activity and most of that energy must be baseload.  That means lots of nuclear power.  And it need to be cheap.

http://newmars.com/forums/viewtopic.php?id=9197

Last edited by Calliban (2019-11-28 12:55:59)


Interested in space science, engineering and technology.

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#28 2019-11-28 13:22:26

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 19,681

Re: Gravity Energy Storage

Have copied the post industrial

The post is just a scope of what levels of power will be needed in the future and just why its important to save up that energy for later since we are going to be very limited to the type of nuclear power to which early mars will be started with.

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#29 2019-12-11 17:38:40

knightdepaix
Member
Registered: 2014-07-07
Posts: 236

Re: Gravity Energy Storage

tahanson43206 wrote:

mountains-for-long-term-energy-storage-hg.jpg

Can the lower storage site be connected to a Parabolic antenna that received microwave from solar panel in Mars Orbits or Phobos

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#30 2020-01-17 18:35:30

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 19,681

Re: Gravity Energy Storage

We are still talking about the most efficient form of storage and conversion rate for Electricity, Work, and Power

Summary of Force, Work and Power

Force = Energy applied to an object(Measured in Newtons).

Work = Force X Distance, or the amount of heat transferred (Measured in Joules or calories).

Power = Work/Time (Measured in Watts)

Various Energy Units

1 calorie (thermochemical) = 4.184 J

1 Btu = 251.9958 calories

1 Btu (thermochemical) = 1054.35 J

1 kilowatt-hour (kWh) = 3.6 x 106 J

1 kilowatt-hour (kWh) = 3412 Btu (IT)

1 therm = 100,000 Btu

1 electron-volt = 1.6022 x 10-19 J

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#31 2020-01-18 11:17:43

knightdepaix
Member
Registered: 2014-07-07
Posts: 236

Re: Gravity Energy Storage

knightdepaix wrote:

Can the lower storage site be connected to a Parabolic antenna that received microwave from solar panel in Mars Orbits or Phobos

How about installing GES on Olympus Mons? It has a very gently sloping profile, allowing facile maintenance after a road be built from the bottom to the top beside the cable. By the same token are GES systems on Mons of Ascraeus, Aria, Pavonia, Elysium feasible? They are all higher than Mount Everest.

Is the energy from the GES on Olympus Mons enough to support the number of people in Italy or the Philippines?

Last edited by knightdepaix (2020-01-18 11:29:01)

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#32 2020-01-18 13:01:25

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 19,681

Re: Gravity Energy Storage

At the foot of the hill we have potential energy of a mass rise to be stored at the new location at the top of the hill where in the mass is not changing only the initial energy needed to make the change is negative kenetic in the form of eletric expended..We have the initial and final energy lose as well for momemtum. Other loses are in the form of friction to motion.
https://en.wikipedia.org/wiki/Potential_energy
https://en.wikipedia.org/wiki/Kinetic_energy

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#33 2020-03-29 11:52:04

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 19,681

Re: Gravity Energy Storage

tahanson43206 wrote:

This post is offered for Calliban ...

https://www.yahoo.com/news/feature-zero … 42337.html

As I read this article, it ** sure ** sounds like the pumping technology Calliban brought to our attention some time ago.

Edit#1: The technique I'm recalling was compression of gas by a falling column of water. Developed for use in early (17th/18th Century) mining operations.

The method appears to draw energy from a large downflow of water to lift a small volume to altitudes where it is needed.

While this post is in Technology Updates, it involves a modern use of what must be an ancient technique.

(th)

The real trick is how to get the water up to the storage area without expending energy to move it there. Of course this is where some claim free energy for use is excess energy production from solar, hydro ect... which does not have a buyer for the energy and since that is in AC form we need to convert that to a storeable. That is where efficiency losses come into play for convertion, storeage and later use of it.

1. One method would be is to use rain water that falls into catch basins along mountian water areas. so as to keep it in an elevated state for later use.
2. Another such area to do the catching would be road side drain systems to just send it to ocean going streams.

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