We are currently in the process of evaluating placing solar panels on our roof. The south facing roof with best sunlight currently has a plumbing vent that would be nice to move if possible.
My plan is to reroute the plumbing vent using two 45 degree elbows, and routing the new vent higher up on the roof, as well as patching the old hole and re-shingling.
Does this renovation makes sense and am I overlooking anything or possibly breaking any codes/best practices?
Your plan looks fine to me assuming this isn't an absurdly long run that exceeds code requirements at that size. You'll need to support the pipe, so it may actually make more sense to use 90° elbows and keep the horizontal run down low.
You only need 1/4" per foot slope once 6" above the flood rim of the highest fixture served by the vent. Presumably that's true anywhere in the attic.
Assuming you are in an area where attic may be cold, it's arguably better to run at 1/4" per foot (or "plumbing horizontal") down in the insulation, and then have a short vertical run out the roof, rather than having a long 45 degree frost-collector to get the same movement. It's not uncommon to collect all the vents in the attic so there's only one roof penetration (though it's also not uncommon to have a roof penetration for every branch vent, but it's a tradeoff that I'm not fond of.)
