LITTLE ROCK, Arkansas, April 2 -- Southwest Power Pool, a corporation mandated by the Federal Energy Regulatory Commission to ensure supplies of power, transmission infrastructure and wholesale electricity prices, issued the following news release: Southwest Power Pool (SPP) reached a significant milestone in the development of its western day-ahead electricity market on Friday, March 29 when it filed its Markets+ tariff with the Federal Energy Regulatory Commission (FERC). The achievement unde  more