[PMC Weekend Edition] Mailbag: Giant flywheel of death

I got the best response to last weekend editions’s Giant flywheel of death email. THE. BEST!

This came from Luca, who was on my podcast a while back. He said:


There’s a fusion reactor at Munich technical university. Its ridiculous power draw is satisfied by a giant flywheel.

During planning, someone calculated what would happen if the thing broke free. They calculated it would go straight through Munich, and then about 50km further; pretty much right to the foot of the alps. IIRC they actually decided to orient it such that it would roll uphill if it were to break free, lest it go even further 😀


I was thinking about this for DAYS. I looked it up and found this picture for you of the flywheel:

Here’s the description:


The electric energy needed by the ASDEX Upgrade fusion experiment to power its magnetic field coils and plasma heating facilities is supplied by large flywheel generators. An experimentation pulse in ASDEX Upgrade requires an electric power of 400 megawatts lasting 10 seconds, i.e. half as much as the whole district of Munich. Such an abrupt grid load is not permissible; so the electric energy for ASDEX Upgrade cannot be taken directly from the grid. Instead the flywheel generators gradually take the energy needed from the grid, store it and then pass it on to ASDEX Upgrade in a single pulse.

The biggest flywheel generator at IPP can store 1,514 megajoules or 421 kilowatt-hours of useful energy. It is used primarily for the main field coils of ASDEX Upgrade. The 220-ton flywheel is accelerated in 30 minutes by a grid-supplied drive motor from stationary to 1,650 r.p.m.. Its circulation velocity can attain 900 kilometres per minute, i.e. almost the speed of sound.

During an experimentation pulse the flywheel then drives a three-phase generator, whereupon it decelerates to 1,270 r.p.m.. The three-phase generator can supply up to 155 megawatts of power for about 10 seconds. Once it has unloaded, the flywheel generator is restored to full power every six minutes.

Source: www.ipp.mpg.de/4244138/generatoren


So the Munich flywheel is different than the one my friends and I like to imagine, but it’s still some serious poetry-in-motion kinetic energy!

Thanks for that share, Luca!

Happy Sunday,

-P