Advanced Rail Energy Storage

Here is a novel application of Railroads. The company proposes to use electric powered trains to storage electricity for the commercial grid. Cars would travel up a 7% grade over 5.5 miles to store electricity and down the grade to re-generate it. An efficiency of 80% is claimed.

http://www.aresnorthamerica.com/

9600 tons on an 8% grade? Seems to me the cars would need ECP brakes to maintain high tolerance balanced braking - and that would limit the amount of returnable energy from the locomotives. Good thing they're in the desert because they'll be using a lot of sand on the rail. Sounds like an enormously expensive pie-in-the-sky money-loser to me. Must be getting serious grant funding from some government entity....

The traction problem makes me wonder why they didn't opt for a cog drive. Not only would it reduce slippage on the proposed grade it could also enable higher grades.

I don't have the relevant numbers, so can't begin to evaluate the proposal. Still, the basic idea that you can store energy by moving something heavy uphill and then recover the energy when it comes back down is valid: I believe that there are places where just that is done with water: pump water up into a high-elevation reservoir at low-demand parts of the day and run it through hydroelectric turbines at high-demand times. In a railroad context, there was once an electrified mining railroad (Lartigue system monorail, but hey…) where the mine was at the top of a hill so loaded trains were mostly downhill. Supposedly enough energy was recovered to pull the empties back up for free!