Decrease the PGA memory

Hi everyone, 

I have an oracle DB and in SQL Developer i built my DataWarehouse i.e i built all of my view and transformation of my Data in the proper structure for me. 

The problem is that in that instance we have limitation in PGA and when i refresh either I get an error or other users that query the DB for SSRS etc they are getting a PGA error. 

There is no option for now to exctend the limits of PGA, so i would like to ask is there a way to not take so much PGA when i refresh ?

I was thinking to move everything in SSMS all the initial Views and create the rest of the complex views there and then connect the ssms with PBI. But i don't know if it makes sense. 

A second option that i thought is the incremental refresh, so to load everything once and then with some flags i guess i will update only new data if that possible. But again i need SSMS for that as i read.

So since i am not so expirienced with those processes do you have any ideas of how i can achieve this ?