Tom,  This is where the real issues of distributed generation comes today.  Besides the fact you can't control these types of generation and we have no viable way of story it on a large scale.  There is another issue - en-mass wind farms and PV generation does not connect to the 275/400kV network like conventional plants do.  Ridiculously large scale investment is needed on the lower voltage levels to make it work.  And this is where the smartgrid idea comes into play because in this theory - the 400kV network becomes redundant.  Please do a video on smartgrids, talk to one of the local RECs about it and see what you find.