Solar plant in SEZ unit - Goods and Services Tax - GST

Dear Experts, I have a client (a DTA ) who wishes to set up a solar power plant at SEZ site to supply them electrical energy but is prohibited to register is a its additional place of business. the plant will be owned and operated by my client. what implication it may face due to this restriction. also if they are not allowed to register it as its additional place of business how can they manage entry of materials necessary for installation and operation of plant at SEZ site ?