It is a transmission line that is part of the overall national strategy to increase reliability and connectivity. The ERCOT market is different from the rest of the country, which is a federal jurisdiction. Different rules that make electrical trade illegal/incompatible. For the ERCOT market, it means it can, under emergency request, draw energy from MISO-S region, instead of burning coal & oil emergency stockpiles. While the same line provides additional reliability and throughput for the MISO-S region.