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Energy Recycling Gives Subways a 'Brake' on Bills

Science & Tech  (tags: research, scientists, science, technology, environment, energy, recycling, sustainability, Gizmos, design, concept, mass transit, subways )

- 1801 days ago -
Getting thousands of tons of steel, plastic and people moving along an underground track clearly takes a lot of energy. Less known, or at least less thought of, is how much energy it takes to stop.

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Michael O (176)
Saturday July 13, 2013, 8:51 pm
By M.Corey Goldman, Financial Post

While the high-pitched screech of a subway train coming to a halt is a good indication, the energy produced by brakes on metal isn't something most would consider possible to harness and re-purpose.

Andrew Gillespie is the exception. Mr. Gillespie is the chief engineering officer for power at the Southeastern Pennsylvania Transportation Authority, or SEPTA, the transit network that moves some four million people in and around the Philadelphia metropolitan area.

He and his colleagues have been intently watching over a test system currently running on a portion of SEPTA's rail transit line that allows captured energy from one train slowing down to, among other things, propel another train speeding up - a system provided by the Canadian arm of ABB Systems Inc.

"We consume about a half a billion kilowatts of power annually; my electric bill is anywhere from US$38-million to US$42-million," Mr. Gillespie says. "This is a technology that makes the whole system more efficient."

Like a hybrid car, ABB's solution is a way for mass transit systems to store and re-use dissipated braking energy as a means of saving money, boosting efficiency, being more environmentally friendly and even making money by selling some of the stored-up energy. Newer trains and streetcars have "regen" capacity

built into their braking systems. It's an innovative project initially conceived in the suburbs of Montreal by Jacques Poulin and a team of engineers at Envitech Energy, a company that had focused its efforts on solar-and windgenerated water treatment technologies but later moved into rail transportation. ABB, a global power and automation technologies firm, acquired LandTech Energy in 2011.

"It's an emerging technology that transit providers are starting to consider and explore, because it can pay for itself," says Mr. Poulin, product manager of energy storage in rail transportation at ABB's Point Claire, Que., facility. "It also helps reduce the carbon footprint."

While efficient at moving hundreds of people at a time, subways, streetcars and light rail lines aren't so efficient when it comes to energy consumption. Power consumption has risen significantly in the recent past with cities adding more electric-powered vehicles to their transit networks that include creature comforts such as air conditioning.

That's where ABB's system comes in.

Using a wayside, or "beside-the-traintrack," energy storage solution, the system detects when a train is braking and the voltage is rising, automatically taking that energy flow into an 800-kilowatt lithium-ion battery, or sending it back out when it detects another train accelerating.

If there isn't a need for the extra power stored, it can be sold back to the wholesale energy market, or the grid. Most riders wouldn't notice the equipment, which consists of a large stationary battery housed in a white cargosized container, and a smaller grey box beside it that controls the system.

Thanks to energy market de-regulation, U.S. energy providers can buy energy from private producers - companies or even individuals with solar panels or wind turbines, or a public entity like SEPTA. PJM Interconnection, the Eastern regional grid operator, has teamed with SEPTA to buy energy when

it needs to balance out electricity supply and demand.

So far it's paying off. Since coming online last April, SEPTA has seen a nearly 20% reduction in power consumption at the substation, Mr. Gillespie says. The longer-term objective is to bring in from $150,000 to $200,000 a year in revenue, giving SEPTA a way to finance installing more systems along its network.

"We're seeing savings of anywhere between US$12,000 and US$20,000 a month," he says. "That's electricity that doesn't have to be produced, which means more cost savings and, equally important, less emissions."

Other cities have also begun to sign on for the new technology, including AGP Metro Polska, which runs the metro system in Warsaw as well as Montreal's STM, which in a few weeks will have a test version of ABB's system up and running on one of its "Arriere Gare" (literally "behind station") tracks. A spokesperson for STM confirmed that the project was underway.

For Philadelphia and other cities where the technology may eventually get rolled out, riders won't notice any difference.

"They actually won't notice it at all," Mr. Gillespie says. "The analogy I use a lot is it is the transit equivalent of a Toyota Prius [except] there's no room left to put the battery on the train so we put the battery on the wayside instead."

David C (25)
Sunday July 14, 2013, 12:22 am
interesting topic, but this article certainly isn't one of the brighter bulbs on the Xme$$ tree, to put it mildly ...

to start with, it's about 20(-30?) years late. That's when Wirbelstrobbremsen were introduced, for railways and subways (and methinks even some Trams) hereabouts. and AAB/SEPTA are already starting with TESTsystems???

it seems to tell us brand names and does not name the method, or does it. Its called iianm Wirbelstrombremsung in German, which translates to eddy-current braking [tech.]

then some outright BS:
> Like a hybrid car =BS
> ABB's solution
"solution" as in test-system of a method otherwhere implemented many years ago ???

> even making money by selling some of the stored-up energy.
Lowering, to a certain extent, consumtion and cost - yes
"selling some of the stored-up energy" = BBS, please get real!

"store" Energy = probably a pure lie. And not necessary, too, of course...

> Toyota Prius
do they get paid for product placement ?


Freya H (357)
Sunday July 14, 2013, 7:36 am
Kewl! Every bit of energy saved is good. Braking wastes a lot of energy, so when you can convert the effort of braking into another form instead of simply dissipating it, that helps a lot. Darned clever of those Toyota technicians to make braking work for the Prius.

Roger G (154)
Sunday July 14, 2013, 2:23 pm
noted, thanks!

Sheila D (194)
Sunday July 14, 2013, 5:42 pm
WOW! This would really make a difference, especially when you think about the possbility of all underground transportation being hooked up. Look forward to updates. Thank You.

David C (25)
Wednesday July 17, 2013, 1:39 am
> Wirbelstrobbremsen
(apologies. Stupid typo!) should read Wirbelstrombremsen (of course. I(diot) once again forgot to spellcheck)
> Braking wastes a lot of energy
With cars only or at least mostly if the driver drives stupidly (as opposed to anticipatory)

Once i also earned some money as driver (for film productions). First time i filled up the tank of the Mercedes 350slx(or similar)(automatic) i had used/wasted ~15 l/100km. A couple of weeks later i was down to (even slightly below) 10 l/100km .. and i got everywhere just as well.
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