The remaining amount of MWs available for generation outages to be scheduled for the given day. This number is calculated from a SPP BA Capacity standpoint. Example: If a given MKTDAY has 500 Additional MWs Available for Maintenance, then an outage submission of a generator across that MKTDAY with a max capability of up to and including 500 MWs would be acceptable. An outage submission of a generator across that MKTDAY with a max capability over 500 MWs would be denied. Please note that this margin is one of many criteria used in determining if a generation outage may be approved. A generation outage may be denied for other reasons even if it falls within the acceptable MW range based on the calculated margin.