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Underground > Laboratory >

Cars generating power? Bullshit, buck-passing or bad science?

16:24 / 01.08.04

There's an article here about a hybrid car which is able to put "excess" electricty back into the grid system. Now, call me a bit dim if you must, but where exectly does this excess come from?
Hypothesis 1.
If it's just leftover power in the battery after use, that's fine, but surely in order for the car to work properly later, you'll just have to pull it back out again later.

Hypothesis 2
While the electric power is not in use, and the hydrocabon fuel source cuts in, then some of its energy (kinetic or otherwise) is used to generate electricity which is then stored in the battery. Probably more than the car needs. Ok, I can see how that might work.
Doesn't this mean that the car has been designed to be inefficient? It's actually using MORE HC fuel than it needs to get from A to B in order to generate this power. Given that in each transition, energy will be lost, this idea seems really quite counterproducticve.
Stoopid, even.

Hypothesis 3
Small green electricity fairies rub up against your hair while you drive and syphon off the static.
That must be it.

17:47 / 01.08.04

Being as how the article is from the Christian Science Monitor, I'm going to plump for option D - Bad science. As the Christian Scientists also believe that prayer, not actual medical treatment are the best way to treat illnes and injury I don't feel that their theories on science are to be trusted.
But then again my knowledge of electrical science is not great, so I could be wrong, but it seems to be too good to be true in my opinion at least.

18:43 / 01.08.04

Aha. I read so many blog links, I'm beginning to forget to check the source. Still, Boingboing plugged it without comment. They normally rip such stupid ieads apart.

10:56 / 02.08.04

This seems like a good idea to me.

Fuel cells are 80% efficient and are much less harmful to the environment than C02 producing power stations (which are only approx 40% efficient).

As the article states, they could be used to "fill in the gaps" of the power supply during peak hours.

11:11 / 02.08.04

The problem is you still have to charge your fuel cell, and at the moment that basically means burning fossil fuels. Fuel cells are much more like batteries than actual generators and it only really makes sense to use them as part of a wider strategy involving renewable or other non-polluting energy sources.

12:28 / 02.08.04

Fuel cells are 80% efficient and are much less harmful to the environment than C02 producing power stations (which are only approx 40% efficient).

What exactly does that mean? That the cars are able to transfer 80% of the energy of fossil fuels into the cells, I assume. However, a more efficient use of those fossil fuels would surely be to power the car's engine. Given that car engines are surely better than 80% efficient in transforming the fuel into kinetic energy, that means you're wasting the difference between their efficiency and that 80%. Any further use of that electricity will also mean a loss in efficiency, and even more waste.

As the article states, they could be used to "fill in the gaps" of the power supply during peak hours.
How? I can sort of see how a distributed model lots of cars with small bundles of energy in their batteries sitting around waiting to be tapped might work. Even if, as I think you might be saying, the cars are twice as efficient as power satations at converting fossil fuels into electricity as power stations, you still have to contend with an awful lot of fuels being burned, usually right next to where people live. The high efficiency must assume that the fuel is already in the car. The waste in distribution of getting the fuels to cars scattered all over the place must be very high, no?
Just not sold. I really want someone to explain the model properly, and I can't find anything out there. It's almost as wooly as the hydrogen cars concept. Great idea, sloppy thinking.

Cheap. Easy. Cruel.

14:18 / 02.08.04

What I get from the article is that it is not any new technology. Merely using the "excess" power that is stored in the battery to power the grid.

So you are using your car as a small power generator. As far as making your car payment with the electricity you sell back to the power company, that is complete bullshit. This is more about the power companies needing less full capacity operating time on their generators. It will allow them to tap an, as yet, unused resource during peak hours.

17:49 / 02.08.04

It's unfortunate that you found this article on the Christian Science Monitor as it has made people here assume it is bad science. It isn't scientific reality yet but serious reserach is being carried out in this area.

A Google search for V2G turns up this site for the Vehicle to Grid Power research program at the University of Delaware.

Hopefully it can explain things better. I won't try to write a summary of the information here as I'll probably make errors and make things more confusing.

In environmental terms V2G is less good than a move from traditional power stations to renewable energy sources. But it is clearly more efficient to generate electricity using a fuel cell in car than a traditional power station if the figures of 80% compared with 40% quoted by Atyeo are accurate.

The car will be less efficient than it could be but the system as a whole will be more efficient, because every bit of extra fossil fuel that's used in the car a greater amount will not need to be burnt in a power station.

20:13 / 03.08.04

Something to bear in mind with hybrid cars is that an efficient car is one that never stops.
In the real world, hydrocarbons have to be converted into forward momentum, right? But that momentum keeps getting wasted as heat (from friction) because we keep having to stop.

Hybrids work by using the braking power to spin a dynamo which charges a battery. It's a way of turning that wasted heat into electricity, instead.

10:41 / 04.08.04

The point that I was trying to make (badly) is this. Power stations produce much more energy than we actually need because it has at least, or close to, peak power output 24hours a day.

This is due to the nature of the beasts, they can't be shut down and restarted to fit in with our tea breaks during Coronation Street ad breaks.

Therefore we are wasting huge amounts of power at night. As we need power for our cars anyway, why not reduce the amount of power in the national grid and support it on peak hours with a more efficient source - fuel cells.

Admittedly, the cars are only 80% efficient from the 40% ie. ~32% (all figures very approx.) but with a reduced mational grid output everyone benefits.

Hooray!

I haven't done the maths so I'm sure I completely wrong but heh, sue me.

With respect to hybrid cars. A massive proportion of energy in car transport is used in acceleration. So when you break the electric motor charges and then kicks in to let you pull away. That's why when there's no traffic about and I'm approaching lights I slow down slightly and try to catch the lights just as they turn green thus saving all that energy.

Well, we've all got to do our bit.