Rivian has reworked its loan deal with the Department of Energy and now expects to borrow $4.5 billion to build its new factory in Georgia, down from the original amount of $6.6 billion allocated under the Biden administration. The company also announced Thursday that it will draw on the loan sooner than planned, in early 2027, and expects to increase the total capacity of the Georgia plant from 200,000 to 300,000 vehicles in its initial phase of operation — another sign that the company has high hopes for its upcoming R2 SUV. The larger capacity — a 50% increase over its initial plans — will help lower its per unit costs, while also providing significant room for future expansion of capacity in later phases, the company said Thursday.  Some of the factory’s capacity will be used to produce R2 robotaxis for Uber.…