Rail Energy Storage System

MikeC

Closed Account
The home page has a fairly good explanation - as the video says it is a simple concept - use excess power generation to push weights up a hill (thus accumulating potential energy), then drive generators by letting the weights back down the hill to generate power when required.

It works for me as a concept - good luck to them!
 

Keef Wivaneff

Banned
Banned
From the patent application;
FIG. 11A shows details of an exemplary implementation of the beginning track sections of a power and return track system. The specific elements of each ARES system facility will vary with its intended storage and generation capacity, the elevation difference between the upper and lower yards and the grade. An ARES facility with a 3,600-foot elevation difference between upper and lower storage yards and an average inter-yard grade of 7.5% will be able to charge or discharge at 1,000 MW while providing 8000 MWh of net energy storage.
http://www.freepatentsonline.com/y2011/0037275.html

The steepest railway lines that do not utilize a rack system include:
13.5% (1 in 7.40) - Lisbon tram, Portugal
11.6% (1 in 8.62) - Pöstlingbergbahn, Linz, Austria[2]
11.0% (1 in 9.09) Cass Scenic Railway USA (former logging line)
9.0% (1 in 11.11) - Ligne de Saint Gervais - Vallorcine, France
7.1% (1 in 14.08) - Erzberg Railway, Austria
7.0% (1 in 14.28) - Bernina Railway, Switzerland
6.0% (1 in 16.7) - Arica, Chile to La Paz, Bolivia
6.0% (1 in 16.6) - Docklands Light Railway, London, UK
5.6% (1 in 18) - Flåm, Norway
5.3% (1 in 19) - Foxfield Railway, Staffordshire, UK
5.1% (1 in 19.6) - Saluda Grade, North Carolina, United States
5.0% (1 in 20) - Khyber Pass Railway, Pakistan
4.0% (1 in 25) - Cologne-Frankfurt high-speed rail line
Note that these are NOT freight rail lines but lightly loaded passenger cars.
 

Keef Wivaneff

Banned
Banned
I do agree, it sounds nice.
I actually thought of it myself before I heard about ARES.
Someone did the math(s) and said there were a few problems with the idea.


Ned Ludd writes...

Find a hill, Great dividing range is ideal

I think your train will have problems making it up the hill, especially with a heavy load.

http://en.wikipedia.org/wiki/List_of_steepest_gradients_on_adhesion_railways

Metros and pure commuter railways often also allow higher gradients, up to 4%, for the same reason. High speed railways commonly allow 2.5% to 4% because the trains must be strong and have many wheels with the power to reach very high speeds. For freight trains, gradients should be as gentle as possible, preferably below 1.5%.

Let's be ambitious and say that you can use a 2% grade. You then are allowed to take your rocks UP 1m for every 500m you travel horizontally. Cunninghams Gap (in QLD) has an elevation of 787m. Ipswich (where a lot of the power generation assests are around) has an elevation of 50m. The difference is then 737m. At a grade of 2% your horizontal track then needs to be 37km long. That's not that long (it's about double that from Ipswich to Cunninghams Gap by road), but it needs to be a steady grade, so what you effectively need to do is build a MASSIVE 37km earthen ramp from Ipswich to the Range. Of course you would try to follow a route that included natural hills and other features that could be included in your slope so their is less work for you to do (but then you introduce curves, which have their own problems). I have no idea how wide a base you need to have on your ramp at the end that is 700m in height. Perhaps it wouldn't be earthen all the way, but I doubt you could build an elevated track on any height that would carry the weight without some massive engineering either.

The amount of energy you can store is also interesting. Moving a 150 tonne car (loaded with rock, steel, whatever) to a height of 737 gives a potential energy of 300kWh. Not sure how many cars you'd need to satisfy peak demands, but I believe it would be in the order of GWh's ? To store 1GWh would then require 3333 cars (that's a fair number, I think you're going to need a big loop at the top).

The other factor is how quickly you can generate the power. If it's a 10MW loco then that's what it will both consume as an instantaneous value when it's going up the hill and also what it will generate coming back down. So if you want to generate 350MW of capacity (the equivalent of one of the coal fired generation units at Tarong) then you would need 35 trains coming down the track at the same time. To give 1GW of capacity you need 100 trains in full flight.

Water is good because you can pump it. It doesn't care if the grade is 90% (almost straight up) as long as your pump is powerful enough. But to use pumped hydro you need a location that has space for a massive reservoir at the top, another at the bottom, a large volume of water that you can replenish (ie. a dam on a river) and also significant height differential between the two of them. This is what we're very short on in Australia (and the world in general).
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Now, I don't want to be negative and I wish them all the very best of luck...BUT I do hope it never rains on that 7.5% gradient track! Things might get VERY interesting.
 

Keef Wivaneff

Banned
Banned
Mick, I really don't want to get thrown off the forum so I'm trying to abide by the rules.
Would it be permissible for me to express the opinion that the idea is in actual fact BUNK?

Economic factors not even considered I think a 7.5% gradient track steel on steel is an impossibility.
There is no suggestion that they are planning a rack and pinion system.
If the gradient is reduced to a more realistic 2% then the length of (constant gradient) track needed becomes considerably longer and the cost becomes astronomical.

IMHO the money would be better spent on a more realistic solution to the energy storage problem.
 

Soulfly

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Banned

Keef Wivaneff

Banned
Banned
Pumped water storage is a well proven and efficient method to store energy.
Most Hydro electric schemes eg Snowy Mountains are all ready doing this.
Intermittent renewables eg solar and windpower would benefit from storage capacity.
There is not an oversupply of suitable bodies of water.

New Invention flow batteries, flywheels, gravity-storage, compressed air, clockwork or whatever thingies will be along soon promise (send money now)

Most of these new invention enterprises will deliver only broken promises.
 

Ted

New Member
OK guys... just to give you the engineering reality check...

First - Fly wheels are awesome energy storage when you need a relatively large amount of power for short term ; temp power or large quick discharge. I've seen most applications for temp power for server farms gap power while generators pick up, and burst power for large scale laboratory work - energy weapons, plasma, EMP, lasers and the like. But flywheels only provide energy for seconds... not minutes or hours.

On the pertinent note - use of rail for energy storage and the worry about the steepness of the hill. First of all they have a video on the steep grade, so the pilot scale certainly works; and may be something other than a steel on steel rail. They make gas turbine blades out of unobtanium; and have tens of thousands of gas turbines out there, certain they can make, prove, permit and warranty heavy industrial process rail ways that are not "people rated" that can handle steeper grades using the right materials, this is 2013, not 1965.

Rack & Pinon? That's called a cog railway. We use them in the mountains.

http://www.cograilway.com/

Given the large number of decommissioned "obsolete" diesel electric train engines under 20 years of age equipped with regenerative breaking sitting around north america, you could probably improvise this with existing second hand locomotives. At 3 MW per locomotive, give me a dozen locomotives and I could handle a energy storage for a 30 MW wind farm of PV field easy. All I need is a big enough hill that the locomotives won't slide down.

Seriously though, talking to some power mechanical engineers that do stuff like this as a career; they really liked the idea of doing an rail energy storage yard, and putting it on a cogwail rail on mountain sides; just like the pumped energy storage we have in Colorado now; without the water rights problem. Honestly water is more expensive than coal or natural gas in Colorado so they have been slowly decommissioning the hydro electric plants out here in favor of selling the water.

And really you don't need a locomotive on the rail way. You could use a winch at the top of the hill and then the sliding of the rail wheels becomes a non issue. Seriously guys, don't complain about design limitations, just engineer a solution around it. And considering a whinch would like to minimize path length; maybe you just hang weights off a cliff connected to a winch
 

Mick West

Administrator
Staff member
It all comes down to economics. Nobody is suggesting it would not work, it's just a question of if it's cost efficient, and what the capacity is. It needs to compete with the alternatives:
http://en.wikipedia.org/wiki/Grid_energy_storage

"Engineer a solution" is all very well, but there are theoretical and practical limits to any scheme.
 
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