Fusion energy, perhaps just dreaming..

Energy storage for wind turbines

Just an idea

A common (big) wind turbine has a power of 5 MW. ( see http://en.wikipedia.org/wiki/Wind_turbine )

During one day, 24 hrs, it produces: (24 hrs = 60 s.60 m.24 hrs)

5.10⁶. 60.60.24 J = 4,32.10¹¹J

Could we storage this energy by lifting up a weight? (Similar as a weight driven clock..)

The potential energy Ɛ of a weight (mass) m kg at h meters above the surface:

Ɛ = m.g.h ( g = gravitational acceleration = 9,8 m/s²)

The energy of the wind turbine produced during one day:

4,32.10¹¹J = m.9,8.h

Suppose we lift the weight 10 m, then we need a weight of:

m = 4,32.10¹¹J / 98 ≈ 4,4 10⁹ kg = 4,4. 10⁶ ton

The energy of the wind turbine produced during two weeks stored in a weight at 10 m height:

m = 4,4. 10⁶ ton . 14 = 6,2 . 10⁷ ton

The specific weight of concrete is about 2,3 mt/m³

If the weight is a cubic block of concrete, it should have the dimensions:

6,2 . 10⁷/2,3 = 2,7. 10⁷m³ ≈ 300 m x 300 m x 300 m or => 1,6 km x 1,6 km x 10 m

A little bit impossible...

But suppose we have a hole with a depth of 400 mtr.

The weight to store the energy of the wind turbine of one day:

4,32.10¹¹J = m.9,8.400 => m= 1,1.10⁵ton concrete block = 4,8 . 10⁴m³=> for example 36x36x36 mtr