Power from the people!

July 2, 2008 3:40 AM

The Green Dragon, a roller coaster at Greenwood Forest Park, a family 'attraction' in Wales, generates more power than it uses. How is this possible? It's all those stairs ...

There are three 'components' to the system: the coaster train itself, a tram car, and a piece of 'carrier track' used for raising the coaster train back to the top of the run.

Sequence of operation seems to be something like this:
1) Previous ride is done, the coaster train is at the bottom of the run, as is the tram car. The 'carrier track' is up at the top. The carrier track is linked to the tram around a pulley system, and as it is heavier than the empty tram, it now drops to the bottom, pulling the tram car to the top.

2) While that is going on, the next group of riders is climbing the stairs to the top level of the system.

3) Once the carrier track is at the bottom, the empty coaster train is rolled onto it. The group of riders board the tram at the top, and as this is now heavier than the carrier track, it drops to the bottom, pulling the track and train to the top.

4) Riders get out of the tram car at the bottom, and again walk back up to the top, where the coaster train is now waiting for them. They get in, and enjoy their ride ...

5) Repeat ...

Sample rider report: "I really like this coaster. It gets quite fast when you get into the helix. It's also good for the environment, and good for you with all the walking."

Here is a short YouTube video of the components of the system.

posted by woodblock100 (19 comments total)

Puts the "fun" in "funicular".
posted by DU at 4:36 AM on July 2

and reaches a top speed of 25 mph

Not something I'd advertise but hey, hippies aren't into speed.

Nice idea for a park, snarks aside.
posted by twistedonion at 4:41 AM on July 2

generates more power than it uses

No, actually it doesn't. See, those people eat, and convert food (locally served burgers apparently) into energy, both the energy in their leg power and the heat energy of their sweaty little bodies. When they die, any matter that is stored in their formerly sweaty little bodies becomes food for worms and bacteria and fungi and such. The coaster may run on people power and gravity, that much is true, but it does not generate more power than it uses.
posted by Pollomacho at 5:08 AM on July 2 [2 favorites]

hippies aren't into speed.

As far as I'm aware hippies aren't that picky, and they like speed just as much as pot and acid
posted by gravelshoes at 5:12 AM on July 2

Not something I'd advertise but hey, hippies aren't into speed.

It's not like hippies don't like surfing, skateboarding, skiing, mountain biking or offroad unicycling or anything.

For the purposes of this particular topic, you may label me a hippy. That roller coaster probably sucks. As an idea it's cool, but assuming it has a good safety record, the coaster itself has to be about as thrilling as a lukewarm glass of milk.

That said, I would vastly prefer to climb in excess of 500 feet than wait in line for 2 hours for an A class coaster. There's something just excruciating about standing around and moving a couple of feet every few seconds.
posted by loquacious at 5:13 AM on July 2

So I'm guessing it just flat out doesn't work if only half the quota of people want to ride it? Or is it electrically assisted in that event and only fully efficient at peak times?

Also how does it 'generates more power than it uses'? Surely the only outcome is equal (or a slight loss if you consider the human input).

Cool, though. More things should be like that, then lazy fat kids could have fun and do themselves some good.
posted by Brockles at 5:19 AM on July 2

What happens to the last riders of the day? They get to sleep in until the next batch of people comes in the next morning?
posted by splice at 5:31 AM on July 2

Before we descend into the whole entropy argument, I want to say this is a pretty awesome thing.
posted by Spatch at 5:32 AM on July 2

Before we descend into the whole entropy argument

I see what you did, there.
posted by loquacious at 5:46 AM on July 2

Goddam hippies!
posted by ZenMasterThis at 5:53 AM on July 2

Leonardo Da Vinci, in the 15th century, first sketched out a roller coaster that would work along these principals.
But it's taken over 600 years, plus the hard work and steely determination of a tiny Welsh village, before this masterpiece can finally be realized.
posted by Flashman at 6:03 AM on July 2

What Pollomacho said. There's no free launch.
posted by weapons-grade pandemonium at 7:14 AM on July 2 [2 favorites]

I wish this really did generate more power than it used. Solving the world's energy crisis by riding rollercoasters every day would be awesome.
posted by penguinliz at 8:17 AM on July 2 [1 favorite]

The coaster may run on people power and gravity, that much is true, but it does not generate more power than it uses.

So by the same reasoning you'd say a solar power cell does not generate more power than it uses, because it puts out less energy than it receives in the sun; or a hydro generator does not generate power because it takes more energy (again, from the sun) to move the water so it can flow past the generators than energy is generated?

It's a tautology that if you believe the Laws of Thermodynamics then you're never creating energy if you consider the universe as a whole. A power station or generator never breaks these laws but simply converts energy from one form to another.

It's perfectly reasonable to say that this roller coaster is a generator powered by humans in precisely the same way a hydro-electric generator is powered by water.
posted by lupus_yonderboy at 8:18 AM on July 2

Except the water is smart enough not to pay for the ride.
posted by weapons-grade pandemonium at 8:24 AM on July 2 [1 favorite]

You give me that barking feeling in my dogs....

Aw shit, yeah, that's right, huh!
Rollercoaster of Wales...
Say what?
Rollercoaster, yeah (ooh ooh ooh)!
Oh baby, you know what I'm talking about?
Rollercoaster of Wales...
Oh yeah, its always almost rollercoaster time.
Boardin' you is really slow,
Oh, it's just a rollercoaster tease
(And fuck you, Leonardo Da Vinci!).

Chorus:
Your love is like a rollercoaster baby, baby -
Too much work to ride, yeah (wheeze wheeze wheeze).

Hold on, dad, 'cause I remember CPR
From Health Class, just a few more stairs.
1,2, 1,2,3. The Devil says, "Come ride with me.
And you clowns, push faster on the merry-go-round.
All's fair in a Hellfire fair ground.
Let's go slow. Let's go fast.
Climb those stairs, or I'm gonna whip your ass."

Rollercoaster.
Say what?

I will always be here, but I will never ride.
posted by It's Raining Florence Henderson at 8:32 AM on July 2 [1 favorite]

And due to the vast amount of thermodynamic waste in the human body, it's not even clear that you aren't almost getting something for nothing.

Looking at the amount of energy a person consumes while climbing to the top of the roller coaster as a raw number is like assuming that the person would be lying there dead if they weren't on the coaster. What you really need to do is to compare how many calories would be consumed by climbing to the top as opposed to doing something else right there (let's say a light stroll or even standing there).

Looking at this, I'd estimate that difference at about 500 calories per hour or 2000 joules per hour - that's about half a watt. (500 calories per hour is the energy difference between a slow walk and jogging for an overweight person.)

The reason you're getting the roller coaster for free is it costs a lot of energy simply to keep you operating even if you're just standing there. The marginal amount of extra energy it costs to move you up those stairs is very small by comparison.
posted by lupus_yonderboy at 8:32 AM on July 2

No, the phrase 'generates more power than it uses' to me suggests that the function of the rollercoaster (even assuming the people power is considered free) actually feeds back into the grid.

I think it's misleading. It's not generating power unless it does actually create a greater amount than the system requires. The only way I can foresee that being possible is if the return carriage for the coaster is the same mass as the platform the people use, the extra weight of the people versus the car (which can't be much) is a sufficient gravitational force to drive generators to not only overcome any frictional/efficiency losses and charge batteries (perhaps) but also to raise the car.

I think it is a little bit of misleading marketing/eco-fanciful guff. I can't see how even the 'free' people energy would create enough power to do anything other than run the thing, unless people have to go up and down the station thing twice for each ride (thus increasing the relative people to car mass).
posted by Brockles at 8:46 AM on July 2

Wow, what a bunch of killjoys. OK, in addition to all the concerns leveled already, presumably parts wear out periodically, and they have to be replaced, and the replacement parts have to be machined, and the machining (not to mention materials extraction) probably takes way more energy per year than the coaster could "generate" in a thousand years.

Fine, well and good, it's no free energy lunch. But it's still cool! And it's not as big an energy hog as something that uses electricity to move the cars up.
posted by gurple at 10:46 AM on July 2