atomic_fungus (atomic_fungus) wrote,

#637: A rare day

It's a rare Monday that there isn't something in the news that elicits a comment--or at least a wisecrack--from me. But the scan I made of the usual websites didn't turn up anything that I felt strongly enough about to go to all the trouble of making links and all that.


Someone said something, somewhere, about how global warming research will free us of our dependence on oil. No! No it won't! Research into things like battery technology, new types of fission reactors, and better power transmission technology will help to free us of our dependence on oil. Wasting money on paying people to count tree rings and make up other data supproting "global warming=man made=apocalypse" will only make eco-doomsaying a more common vocation for people who don't want to study a real science such as chemistry or physics.


The most recent article on Damn Interesting is about flywheel technology and how it can save us all from having to use gasoline. *sigh*

The problem with storing energy in a flywheel is pretty basic: if the flywheel comes apart, the energy stored in that flywheel must go somewhere. And no matter how well-designed the flywheel is, some will break, one way or another.

Race cars must be equipped with a way of trapping flywheel fragments; if the flywheel explodes for whatever reason the driver of the car (and drivers of other cars, and spectators) must be protected from the shrapnel. And this is for a basic automotive flywheel, the function of which is to even out power pulses from pistons.

And, by the way, "explosion" is the right word.

The article discusses energy-storage flywheels spinning at 100,000 RPM on magnetic bearings. It gives basic lip service to the safety issues, but the safety issues are the biggest problem.

It mentions that carbon fiber flywheels can store more energy than steel flywheels--but that's not true. They can store more energy in less mass, but that requires a greater angular velocity. Carbon fiber is stronger than steel; but if a carbon fiber flywheel explodes it will release just as much energy as a steel flywheel storing an equal amount of energy. The mass doesn't matter; what matters is how much energy is being stored.

When you're hit by a bullet fired by a gun, it's not the mass of the bullet that injures or kills you; the bullet weighs a few grams. But it delivers a hell of a lot of kinetic energy, and that is what does all the damage. The bullet just carries the energy from the gunpowder to you.

Flywheels have been tried, tested, and researched for decades, and we're still no closer to having anything run off flywheels, because the technical problems are harder to solve than the article lets on. It claims that they are less dangerous than gasoline, but that's not really true--a minor mechanical defect in your fuel system generally won't blow up your car and kill you; out of how many millions of cars, how many blow up per year?

Most of the time an accident won't cause your car to explode (Hollywood theatrics notwithstanding) but a flywheel-driven car would have to be designed to handle the G-stresses of a stop with "brick wall assist". Otherwise even a minor rear-end collision would result in replacing the car's energy storage system, making airbag deployment the second most costly accident-related damage to a vehicle.

And all of this ignores the most basic problem with a flywheel-driven car: the flywheel is a storage medium, not an energy source.

The flywheel is useless unless its spun up; where do you get the energy to do that? The article discusses the issue in the context of driving a generator with the flywheel; when you want to "charge" it, the generator acts as a motor and spins the flywheel to speed. But where do you get the electricity to do that?

Off the grid? Great. Let us know when you figure out where the money will come from to pay for the capacity upgrade that'll be needed. (See my prior posts on the "super capacitor" cars.) Oh, and while you're at it, you might want to solve the minor issue of generating all that extra power, too. Electricity does not magically appear--well, I suppose to some people educated in the government school system it must seem that way--it must be generated, and these days we usually generate electricity by burning coal or oil or natural gas, to boil water, in order to make steam that turns turbines which are coupled to the generators that make our electricity.

Thanks to morons there hasn't been a new nuclear plant built in the US since the 1970s. The NRC received an application for a new nuclear plant recently, and supposedly they're going to have to process about 300 such applications over the next 5 years or so.

But your electric flywheel car--even if they were rolling off the assembly lines now--won't do a damn thing about "greenhouse gases" or "global warming" until the electricity you pump into them comes from a source that doesn't burn oil, coal, or natural gas. (Or anything, "biomass" included.)

It's a great and laudable goal to find other, more efficient ways of getting from A to B. I don't mind the idea of eliminating petroleum from the mix (except for lubricants) and think it's a great idea to stop using oil as fuel. But if you come up with electric cars first and deal with the power generation second, you're only going to shift the generation of pollution upstream: instead of a lot of little sources, you'll have a lot of big sources.

The first step in reducing our dependence on oil and petrochemicals for energy is to nuclearize our electrical generation system. Stop burning oil and natural gas to make electricity; use nuclear power instead. This will do two things: it'll reduce our emissions of "greenhouse gases" (if you're worried about that) and it'll reduce the amount of oil we use.

Phase out coal plants--coal is very efficient, and extremely plentiful; all the coal we use we dig out of our own soil and we can afford to take it easy.

But of course in order to nuclearize our generation system we first have to modernize how we deal with nuclear waste.

The way we use nuclear fuel, right now, is like buying a new car in New York and driving it to Los Angeles. Once we get to LA, we park that car, buy another new car, and drive it back to NY. The slightly used cars pile up after a while.

It's the same with fuel rods. A used fuel rod has to be replaced because a very small fraction of the uranium in it has been converted into other elements which "poison" the chain reaction. These elements could be chemically separated from the fuel, and the slugs could be re-cast and put back into the reactor, good as new.

But no! One of the elements you separate from the used fuel rod is plutonium! We can't do that! Someone might make a bomb!

Spent fuel rods could easily be recycled, but instead we're going to entomb them under a mountain. Because we're worried that someone might make a bomb.

We need to get our collective head out of our collective ass.

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