The Anonymous Widower

Unlimited Energy Is More Than A Pipe Dream

This is the title of a comment in Friday’s Times from Ed Conway, who is economics editor of Sky News.

He says how energy storage will eventually solve our energy supply problem, by storing the energy generated from solar, tidal, wave and wind.

He mentions a storage idea from a company called ARES or Advanced Rail Energy Storage, which uses trains to store energy by pushing weights up hill.

This article from Interesting Engineering is entitled These Cool Energy Storage Trains Simply Work With the Power of Gravity.

This is said.

  • Trains are loaded with concrete blocks.
  • Trains are powered by third rail electrification.
  • Energy is released using the regenerative braking, when the trains come down.
  • Very little environmental damage is sustained.
  • No water is used.

I have a feeling that in the right place, this idea could be made to work.

Consider the following facts and thoughts.

Dinorwig Power Station

Dinorwig Power Station in Snowdonia colloquial known as Electric Mountain is the UK’s largest pumped storage hydroelectric scheme.

Wikipedia says this about the power of Dinorwig.

From standstill, a single 450-tonne generator can synchronise and achieve full load in approximately 75 seconds. With all six units synchronised and spinning-in-air (Water is dispelled by compressed air and the unit draws a small amount of power to spin the shaft at full speed), 0 MW to 1800 MW load can be achieved in approximately 16 seconds. Once running, the station can provide power for up to 6 hours before running out of water.

So Dinotwig can effectively store about 6 x 1800 or 10800 MwH of electricity.

How  Much Energy Would A Train Store?

If we took a 100 tonne wagon and raised it through a thousand metres, it would acquire 0.272 MwH of energy.

On a rough calculation, you would need to raise 40,000 wagons  to have the capacity of a Dinorwig.

That would need a very large marshalling yard at the top and the bottom.

How Powerful Is A Locomotive?

A modern electric locomotive like a Bombardier TRAXX can be as big as 6 MW.

This locomotive doesn’t come with third-rail electrification, but that could easily be arranged.

If it took the train with say four locomotives, two hours to climb from the low to the high yards, this would expend 48 MwH of electricity.

So this energy would be enough to raise about two hundred wagons to the top.

Making All The Numbers Bigger

The numbers seem challenging and I think the idea is only possible with larger numbers.

  • The trains would need to be raised through a much greater height – Say 2,000 metres
  • The wagons would need to be very heavy – Say 2,000 tonnes
  • The locomotives would need to be more powerful – Say 10 MW.

These give the following.

  • The wagon would acquire 10.88 MwH of energy.
  • Each train would expend 80 MwH of energy.
  • A Dinorwig-sized facility would need about a thousand wagons.

Making the components bigger certainly reduced the numbers.

Could A Heavy And Powerful Self-Powered Wagon Be Designed And Built?

Concrete has various attributes including heavy weight, ease of use and affordable cost.

Boat builders have even built high-performance yachts from concrete.

Could it be possible to create a self-powered wagon with the following characteristics?

  • A number of powered bogies, with a total power of perhaps 20-30 MW.
  • Third rail power collection.
  • Regenerative braking to generate power on the way down.
  • A weight of 10,000 tonnes.

I suspect that the engineering exists to do it.

It would also need a very robust railway to carry it.

The potential energy acquired by the wagon at 1,000 metres would be 27.2 MwH.

If the time to get up the hill and the power of the wagon were balanced, I could see an efficient design being created.


This project might just be possible in an area like Nevada, where it could be coupled to massive solar farms, but I believe there are few other places in the world, where it would be as feasible.



May 7, 2017 - Posted by | World |

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