If it is energy you want you don't need to paint the planet black, just build a Dyson-Harrop Satellite [nothing to do with the vacuum cleaner/hand dryer man].
Building a shpere is a bit ambitious as you would need all the matter in the solar system, but a satellite sounds do-able 
In fact any advance civilisation worth its salt will have one hence this paper to detect advanced civilisations by detecting the satellites.
Meanwhile NASA are looking at a faster than light drive so theat we can pay a visit.
The spacecraft does not actually travel faster than light it just bends space around it to achieve the same result - so that is okay then. Apparently they think it can be done without needing several stars to power it.