What is Kundalini? Let me use an analogy. In your house, there is a plug-point in the wall. The plug-point in the wall does not produce any power. Somewhere else there is a huge power station which is producing the power, but it cannot give you power directly. It is the plug-point which gives you the power.
Kundalini is the plug-point - a 5-pin point. You might have heard of the seven chakras. The muladhara is like a plug-point. That is why it is known as muladhara; it means "fundamental." Five of the remaining six chakras are the plug. What is the seventh chakra? It is like a light bulb; if you plug it in, then everything about you glows. If you are properly plugged in, keeping the lights on 24 hours of the day is not an issue anymore because you are plugged into the power source.
Even right now you still have energy. You can read what is written, that means life energies are functioning of course, but just a small part of it is functioning. If the whole of it becomes available to you, if it is properly plugged in, there is no limit to what you can do out of it. Energy is not just in terms of physical energy or activity, energy is in terms of life; the basis of existence is energy.
Now to plug in an appliance, your hands should be steady. In the same way, to put the 5-point plug into the plug-point is difficult for a lot of people because there is no steadiness in their body, mind, emotions or energies. All this yoga is just to get the necessary steadiness so that you can just plug it there.
Yoga is the science of getting the plug properly in so that there is an uninterrupted source of power. Once you are connected to this, naturally you will proceed in the way life should - towards the goal of what life is longing for. You just go straight on because now you are constantly in touch with the power source - that which is the source of creation.