Southern MN and Central IA | Thanks for the Beacon Power, I heard them on NPR but couldn't remember the name.
Regarding the flywheel design, though, if you double the mass you'll double the kinetic energy stored. But, if you double the radius you quadruple the kinetic energy stored so its not necessarily a 1:1 ratio. Conventional flywheels suffer from the material strength issues but with improvements in composite and engineered materials, additional energy storage becomes available. A good example would be carbon fiber and being able to create a non-isotropic carbon fiber flywheel where the material strength is greatest in the direction of the hoop stress. With increased tensile strength, a larger radius can be used and which reduces the RPM requirement. Conventional roller bearings are least efficient at lower speeds but mag-lev bearings counteract this problem and could remove issues with bearing design. Of course, like you said, you'd still have to build a bank of flywheels but I think it is a promising way to store turbine energy. |
Storing windmill power
