Sempra Energy (NYSE: SRE) today (9/13) announced that its Mexican subsidiary, Infraestructura Energética Nova, S.A.B. de C.V. (IEnova) (BMV: IENOVA), has signed a long-term contract with Chevron Combustibles de México S. de R.L. de C.V. (Chevron) for 50 percent of t…