Flywheel energy store

Pincher

They are talking about storing night time electricity in electric car batteries, for use or export back to the grid during the day. The range is already compromised, so it's silly to reduce it even further by using up the battery before you leave the house. However, the idea of storing cheap night time electricity for use during the day is still a good one,
and expensive lithium ion is not the only way.

I seem to remember there was a flywheel suspended by a magnetic axle inside a vacuum, so friction loss is non-existent. The urban eco-hubby will already have a buried rainwater tank in the back garden, but what about the front garden? Without friction, the flywheel module is maintenance free and should last forever. We should be able to bury it with a service channel like the water mains. There vacuum probably will need pumping out as air leaks through the seals, etc.

The storage capacity only has to be sufficient for part of the day, because there can be wind turbine and PV top up. I can see myself catching up on the news while exercycling. Worst case scenario, you fall back on mains electricity supply. So smaller versions can go under the staircase, into the loft, etc.

I think a reasonably priced energy store is the missing piece of the renewable energy puzzle, and is a tremendous market oppotunity.

I suppose a bank of lead acid batteries will do the job as well,
but it's a lot cleaner to recycle a flywheel than half a tonne of lead and acid.

Eric_Pisch

only down side is its incredibly dangerous, plus you need power to maintain the electro magnets and vacuum

as you get up to usable sizes 10kgs+ and with the rpms they where talking about for this 150,000+ the amount of energy is huge, when you get even larger flywheels the amount of energy is far in excess of a 1 tonne bomb from WWII

if the things ever go wrong BOOM!! 6 foot of concrete wouldn't stop it .

Pincher

Oh well, another funky idea down the drain.

thor

Eric_Pisch wrote: »

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if the things ever go wrong BOOM!! 6 foot of concrete wouldn't stop it .

in which case why not use the stored electricity to charge electric cars. As oil keeps getting ever more rare and hence more expensive, I can see electric cars increasing in numbers quite dramaticly out of neccessitation. On windy days you might not even need to use the energy stored in by the flywheels and connect direct to the wind energy grid or whatever system gets set up.
As for the danger, well at least you won't have to worry about naked flames.

shaven-monkey

Steel flywheel floating on a shallow bath of mercury.
Very low friction.
Spinning up and draining energy off the flywheel will be lossy due to inefficiencies of electric motors with high torque and dynamos.
Gearing would also be tricky.

Using your harvested energy to lift a 1000kg weight up a vertical shaft of some sort may be safer if you used a similar drop break to elevators.If it goes wrong (cable breakage or brake failure) you end up creating an earthquake. Which some may see as bad... 500 x V^2 . so if your weight reaches terminal velocity of 320km/h (a very deep hole) It hits the bottom with kinetic energy of an obscenely high number. 31,214,753,848.joules. Somewhere between 3.5 and 4 on the richter scale. At least it's less than a small atomic bomb.... which is nice. Perhaps a series of smaller weights would be better.
Much the same principle as Hydroelectric power except it can be used for storage. Probably not very efficient but with a bit of work it could provide a form of gravity battery for solar pv, wind and any other power generation.
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not that it makes any difference.

Cardew

thor wrote: »

in which case why not use the stored electricity to charge electric cars. As oil keeps getting ever more rare and hence more expensive, I can see electric cars increasing in numbers quite dramaticly out of neccessitation. On windy days you might not even need to use the energy stored in by the flywheels and connect direct to the wind energy grid or whatever system gets set up.
As for the danger, well at least you won't have to worry about naked flames.

The power stored in batteries of sufficient size for a car can produce quite a nice flame(or explosion)

shandypants5

OR, use your cheap electricity to pump water from a low tank to a high tank.

Then let it spin a turbine as it drains back down when you need it.

dunloadin

OR, use your cheap electricity to pump water from a low tank to a high tank.

Then let it spin a turbine as it drains back down when you need it.

Already done on a much bigger scale, Scot Hydro use lochs.

shandypants5

dunloadin wrote: »

Already done on a much bigger scale, Scot Hydro use lochs.

YA, I know... I was going for Irony.;)