Two-Foot NG Railway in Tehachapi - Built in 2015!

[C855B]

Hey, @GaryHinshaw ! A narrow gauge opportunity to model! Not even two miles from the cement plant! No foolin'!

https://goo.gl/maps/udQM3rBM9D6us5Wy9

I was messing around with web searches and ran into this. It is a 21st Century restatement of the oldest RR operating concept there is - a gravity railway. The idea is to use tracked carts as an inertial energy storage system. The carts are pulled or driven uphill when generated electricity is surplus, then released downhill as generation is needed when other sources such as wind or solar are insufficient. It's similar to "pumped storage" hydroelectric systems.

The company is ARES North America: https://aresnorthamerica.com/ . The installation shown on their website is their v2.0 beta, under construction somewhere in Nevada. The drive system is essentially a roller coaster sprocket and chain arrangement with the carts full of rock instead of a cast concrete weight. I think the wear and tear on the mechanicals are going to kill that idea, quickly. v1.0 was each cart as a standalone generator connected to a trolley bar, which also had its issues. Of course, that idea echoes another long-ago 1:1 design, trains going downhill that fed power back into the catenary to be used by trains going up. MILW Western Extension, for instance.

The Tehachapi site is the company's proof of concept installation. Don't know if the location was chosen for being at the base of dozens of wind turbines and that the land was cheap, and hilly, but it made for good PR. From the photographs in the article and my familiarity with the area I was able to triangulate the location of the "railway".

[railnerd]

"Energy Storage"— pull the train up the hill when you have Solar, let it run down the hill at night to help with power loads.

shifting energy loads is startup fodder here— TeslaPower wall was another concept, but there is a bunch more stuff going on.  A former coworker is at a company now building flywheel systems that you bury in your backyard.  Keep it spun up on solar, it turns the generator all night long and provides steady power.

-Dave

[C855B]

Yes... shades of a flywheel system proposed many moons ago for trolley buses. Flywheel in a vacuum chamber was spun-up when running under the overhead, enough energy stored for a mile or so of running independently. I don't recall quite what killed it, but two things immediately come to mind. First was the unpredictability of traffic and having to rescue "powerless" buses, second was the gyroscope effect of a huge spinning mass on a moving vehicle.

[davefoxx]

This stuff is fascinating, but I have concerns when I hear comments like this: ARES CEO Jim Kelly said, "ARES produces no emissions, burns no fuel, requires no water, does not use environmentally troublesome materials and sits very lightly on the land.”

What about getting those cars back to the top of the hill?  Whatever is pushing them is consuming energy that probably does cause emissions or burn fuel.  This ain't exactly a perpetual motion machine.

DFF

[nickelplate759]

Yes... shades of a flywheel system proposed many moons ago for trolley buses. Flywheel in a vacuum chamber was spun-up when running under the overhead, enough energy stored for a mile or so of running independently. I don't recall quite what killed it, but two things immediately come to mind. First was the unpredictability of traffic and having to rescue "powerless" buses, second was the gyroscope effect of a huge spinning mass on a moving vehicle.

I'm guessing that improved hybrid systems (diesel-electric) and  improved battery technology doomed the flywheels.  I've seen trolley busses in China than can run short distances off the wire.

[C855B]

... What about getting those cars back to the top of the hill?  Whatever is pushing them is consuming energy that probably does cause emissions or burn fuel.  This ain't exactly a perpetual motion machine.

The premise is to pair this system with a renewable like solar or wind to compensate for their variability. Or, for that matter, traditional generation, where in low-demand intervals the demand may fall to beneath the minimum operating threshold. Coal/oil/gas generation typically can't be turned on or off on demand, the startup and shutdown overhead is considerable. It can be throttled, however.

That's some of the logic behind electric cars, charge while demand is low, typically overnight. Residential storage walls do the same thing and especially have benefits with demand pricing systems.

[Tristan Ashcroft]

The premise is to pair this system with a renewable like solar or wind to compensate for their variability. Or, for that matter, traditional generation, where in low-demand intervals the demand may fall to beneath the minimum operating threshold. Coal/oil/gas generation typically can't be turned on or off on demand, the startup and shutdown overhead is considerable. It can be throttled, however.

That's some of the logic behind electric cars, charge while demand is low, typically overnight. Residential storage walls do the same thing and especially have benefits with demand pricing systems.

Seconded, it's all about energy storage.  And since the sorts of batteries that require trace elements or other rare things are only so handy if all 8 billion of us want electricity on demand after the fossil fuels run out, the game is to figure out all kinds of ways to use wind and sun and whatever else to store energy (make a thing go uphill), then release it (let the thing go downhill) when the sun goes down or the wind stops.  In places with topography and water, pumped hydro is quite handy (there's a significant pumped hydro facility on the east side of Conowingo Dam, for example - Conowingo is on the Susquehanna River around the PA/MD border, also has significant conventional hydro power, which is energy storage in it's own right).  In the desert, they have plenty of topography, but no water.  Hence, this.  Heck, who knows, it may even work.

And, tres chic.

Also, I knew have been attempts at setting up large flywheels in stationary settings to store energy, I never knew anyone tried them in a machine that had to accelerate in any way.  That must have been a short-lived experiment.

[GaryHinshaw]

Neat development.  I wish I had the real estate to model it.

Being a physicist though, it does beg the question: how much energy can one of these trains store, and how does that compare to typical household consumption?   Let me start with a system where I know some of the number off the bat: a loaded grain train at the summit of Tehachapi pass.  The gravitational potential energy, E, stored in such a train is E = mgh, where m is the mass of the train, g = 9.8 m/s^2 is the acceleration of gravity, and h is the height of the hill the train will descend when it gets converted to kinetic energy (and eventually, electricity).    Let's take the mass to be 10,000 tons (100 cars, each loaded with 100 tons), which is about 9 million kg.  The height of the pass is almost exactly 4000 ft and the base of the hill at Caliente is about 1200 ft, so let's say h is about 3000 ft, or 1000 m (1 km).  If I did my math correctly, I get:

E = 9e6 * 9.8 * 1000 = 8.8e10 Joules = 24,500 kilowatt-hours

This is about twice as much electricity as a typical American household uses in a year [1].  (Ignoring questions of efficiency, this is also how much energy the locomotives need to produce to get that train up the hill...) 

Now suppose you want to release this energy during peak times.  You would let the train roll down the hill and generate power over the course of, say, 10 hours, then move it back up at night.  During production, you could generate maybe 2500 kilowatts (again ignoring efficiency losses, which are significant).  How many homes could that power?  A typical American home uses ~10,000 kilowatt-hours per year [1], which is an average power consumption of 1 kilowatt (~10 100-watt light bulbs burning continuously), so you might be able to supply ~2500 homes with that system during energy production.  But efficiency losses will cut that number significantly, so more like hundreds of homes in practice.

What about our narrow gauge prototype?  Very roughly it maybe has one tenth the mass and one tenth the elevation change, so one hundredth of the stored energy.  So you could buffer 10's of homes with such a system.  Not too bad for a prototype.

[1] https://www.eia.gov/tools/faqs/faq.php?id=97&t=3

[Chris333]

I was just typing the same thing, Gary beat me to it   

[R L Smith]

I'm guessing that improved hybrid systems (diesel-electric) and  improved battery technology doomed the flywheels.  I've seen trolley busses in China than can run short distances off the wire.

My employer builds streetcars with off-wire capability, and we're running in Dallas, Detroit, Oklahoma City and Milwaukee.  Cars for three other cities are under construction now.

https://www.brookvillecorp.com/streetcar-modern.asp

Ron

[nkalanaga]

Astoria, Oregon had an off-wire streetcar years ago.  It towed a generator on a flatcar!  The same thing could be done today by museums, using a battery car, and recharge the batteries overnight.  It might not look good, but it would be clean, and the only sounds would be those of the typical streetcar under wires.

[John]

I was just typing the same thing, Gary beat me to it   

[wcfn100]

Astoria, Oregon had an off-wire streetcar years ago.  It towed a generator on a flatcar!  The same thing could be done today by museums, using a battery car, and recharge the batteries overnight.  It might not look good, but it would be clean, and the only sounds would be those of the typical streetcar under wires.

There's one in Issaquah WA too.

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Jason

[CRL]

Astoria, Oregon had an off-wire streetcar years ago.  It towed a generator on a flatcar!  The same thing could be done today by museums, using a battery car, and recharge the batteries overnight.  It might not look good, but it would be clean, and the only sounds would be those of the typical streetcar under wires.

It would only be as “clean” as the power grid being used to recharge the batteries and may give the riders a misplaced sense of well being since they think they are riding a “clean” electric trolly, but if it’s recharged from a “dirty” grid, they’ve only transferred the problem elsewhere. Same issue with electric cars causing strain on already overloaded electric grids which don’t have the capacity at present to recharge all the electric cars that some people want to mandate. Astoria may get it’s power from hydroelectric, which is clean, but it still has a capacity cost.

[jagged ben]

As good as Gary's math is, thinking in terms of powering a number of households for 10 hours doesn't really get at what the company's Nevada facility will do.  It will provide " ancillary services for the California Independent System Operator (CAISO)", which is the grid for most of California.    Which means that it will help keep the grid stable, particularly during afternoon 'ramping' when the CAISO switches from mostly renewables to mostly natural gas and imports.  As I type this, CAISO is getting 80% of its power from solar, wind, geothermal, and other 'renewables'.   In 12 hours it will be roughly the opposite. 

Most likely the ARES nevada facility, assuming all goes as planned and it gets up and running, will show up in the 'Batteries' graph on this page.   Grid storage has been ramping up for CAISO.  Since the last time I perused that page, they've changed the scale of the Storage graph from 250MW to 500W.  The ARES facility would be another 50W potential participant in that graph.   As you can see from the daily graphs, the batteries on the CAISO system shift from charging to discharging, or shift the magnitude of the input/output, on pretty short time scales.  That is, big shifts within an hour in some cases, especially during early evening.  As I understand it, they act as a buffer for other plants (e.g. nat gas) that are slower to ramp up.  (Nat gas is much faster to than coal or nuclear or just about any other source besides energy storage.)  Once those other plants ramp, the storage will go back to idle, or even charge for a bit, before discharging to help the next round of other plants ramp.

The facility will be able to make money doing this because it will charge when spot prices in the CASIO market are at or below zero, and discharge to provide the buffering services during ramping hours at a premium because they will be a very dispatchable source.    At 20 acres, the facility will use something like twice as much land as a battery facility made up of Tesla Powerpacks that could deliver the same power.  However, it seems it may pack a lot less energy capacity, if it can only run at full power for 15 minutes. (Most likely it will rarely run at full power.  But Powerpacks could run at full power for 2 hours.)    Adding more capacity would require more 'yard' for mass cars at either end, or more parallel tracks, thus more land.