You can't exceed 360 degrees in bends, with any pipe run. In order to "reset" the bends in your pipe run, an electrician can use a "pull point" which can be an "LB" or a J-box of some kind. Fun stuff.
EMT is necessary inside of homes for solar, because in the event that there is a fire in your home during the day, the idea is that a fireman cutting through a wall with solar current running through it will not get electrocuted (nor you or anyone in the future who decides to do some renovations).
The NEC is designed to prevent fires, primarily, but it also keeps people from getting electrocuted, which is also quite useful. Make sure that you have a licensed, experienced electrician on site, constructing your PV system's conduit run.