FlyWheel Battery

--- In ssi_list@... "victoriatangoman"
> What would a flywheel capable of storing 1,833 kWh look like?
>
> Recall that a watt is a measure of power. A joule is a measure of
> energy. 1 watt = 1 joule/sec, therefore, 1 kWh = 3,600,000 Joules.
>
> We need to store 6,598,800,000 Joules for the average house to
> buffer reduced electrical generating capacity over the course of a
4
> month winter season.
>
> Rotational Kinetic Energy = 0.5(0.5 * Mass * radius^2)*angular
> velocity^2
>
> Let's assume a flywheel operates at 3,000 r.p.m.
> Let's assume a flywheel radius of 1 meter.
>
> Solving for Mass, the formula would be:
>
> Mass of Flywheel = KE / 0.25(radius^2)(r.p.m.)(2PI/60 rad/s^2)^2
>
> Rotational (angular) velocity is (3,000 rpm)*(1 minute per 60
> seconds)*(2 pi radians per revolution) = (3,000)*(1/60)*(6.283) =
> 314.1 radians per second
>
> 6,598,800,000 J / 0.25(1 meter)^2(314.1)^2
>
> The mass of the flywheel = 267,540 kg.

Just to put this mass into perspective consider the Space Shuttle
External Tank with a mass of 29,900 kg.

http://www.usafa.af.mil/dfp/cockpit-phys/mr1ap3b.htm

Each home would need the mass of nearly 9 Shuttle External Tanks in
a flywheel system in order to buffer energy production over the
course of a year so as to minimize solar PV array deploument. 9
Tanks per household! All this metal mining and refining are good for
the environment?

Who still thinks batteries are a good idea?

TangoMan