Having worked with utilities across the country my first thought was Recycling Program Cost or Reactive Power Cost which I've seen on some utilities bills. I hadn't noticed my CSU bill is listing RPC in the electric portion until your question and me looking at it. In the COCS city document of all listed fees from Aug 2024 the $0.018/kWh charge on electric bills is listed as the Transmission Delivery Adjustment fee. Not sure why they don't have it listed as TDA on the bill then.
Just a guess since it is the exact same as the Transmission Delivery Adjustment but since CSU buys their power on a wholesale contract rather than generate their own this could be to recover contractual wheeling costs they have to pay third party transmission line owners to rent firm space on the other utilities transmission line and guarantee CSU's power flows from their wholesale provider to get to College Station even if the 3rd party transmission owner could make more money carrying someone else's power. (shut CSU power out). The alternative would be for CSU to build their own line in that location which would be very expensive. Many utilities I'm familar with fold this into their regular electric rate but some like to show it as a line item for a reference point regarding its cost. That is my best guess.