It can achieve this by prescribing the optimal size of an RTO and then ordering the affected transmission owners to join it. Or it can encourage close cooperation between RTOs that have been formed voluntarily. FERC has chosen close cooperation because it has already decided that membership in an RTO should be voluntary. Close cooperation between RTOs depends on a continuous flow of information between them. The information is used to minimize costs and reduce transmission congestion.
Less congestion increases the output of power plants.
Lower transmission cost increases the feasibility of transmitting electric power from a region with surplus capacity to a deficient one. Both these outcomes increase the supply of electricity. Build new power plants here are limits to how far electricity can be carried over transmission lines, which restricts the supply made possible by close cooperation between RTOs. Distributed generation also has limited economic applications. Treating electricity as a commodity can increase power supply only if it reduces the market power of the existing generators.