Arizona Public Service Company (APS) initiated an expansion of its existing PCI platform to prepare for the California ISO energy (CAISO) imbalance market (EIM). PCI will provide APS with all major system upgrades to fully participate in CAISO EIM. The system upgrades include the EIM software platform that will fully support all APS bid-to-bill and scheduling needs for marketing and trading activities and balancing authority operations. In addition, PCI will upgrade the existing PCI optimization system to be fully compliant with CAISO EIM modeling needs and augment APS outage management systems to communicate with CAISO systems.