Question
noticed bark off in big spots on tree:greenish
powderly stuff on those spots: top of tree bear
braches and some with dead leaves.think maybe lightening stuck tree: tree is close to house and electrial service. do we need to have tree cut down now or try to save part of it.
the electric company said they would cut it down.  

Answer
I would take it down and if the power comapany would do it I would let them and thank them.
It sounds like the tree is being attacked by a fungus called hypoxylon. This disease infects trees that have been weaken by other damages such as lightening. Here is a web site that gives more information of hypoxylon. But if the tree crown is dying there is not much that can be done except removing it, Sorry!
http://www.fs.fed.us/r8/foresthealth/pubs/oakpests/p54.html