How do extra dimensions affect energy conservation?

[almo]

Just finish watching hangout with cern..
Thats a part when the theorist explain abt conservation of energy that seems very vague.
He explained that, with extra dimensions, we could observed that energy is not conserved. And he added that it might have relation to a lot of things, such as dark energy.
But I still don't quite understand.
I understand about the part that, we might be unable to observe high dimensions and energy from the higher dimensions. But what about, if the model of extra dimension prove to be true, is energy still the energy that we understand? How does energy, transverse from the dimensions? Will there be new forms of energy? Will the way where by energy warp space be the same?

 

[jedishrfu]

You could look at it like this:

In 3D, a velocity vector is <vx,vy,vz> and an objects kinetic energy would be described as:

1/2 m v^2 = 1/2 m vx^2 + 1/2 m vy^2 + 1/2 m vz^2

Now suppose we lived in a 2D world then KE = 1/2 m vx^2 + 1/2 m vy^2 for the same object.

The vz component of its KE is hidden from us.