How many joules is 2.04 meters?

Joule is a unit for measuring energy. Meter is a unit for measuring length or distance. There is no conversion. If you wanted to find the potential energy of an object, 2.04 meters off the ground, then you would need to know the mass of the object and the value of g (gravitational acceleration) at the point where you are, then you could calculate energy in Joules.