Polaris' PSO is a production cost market simulator that supports the modeling of multi-level, nested time intervals that simultaneously optimize energy and ancillary services dispatch, and can simulate uncertainties. PSO has all the capabilities of traditional simulation tools and is unique in a number of features that:

• Support decisions at various overlapping time frames (year, month, week, day, hours, minutes)
• Flexibly model intra-hour dynamics
• Simulate user-defined individual ancillary services and products
• Simulate forecast uncertainty for load and generation through user defined probabilistic parameters or historical time series
• Explicitly value uncertainty through reserve deployment and response to contingency events
• Perform stochastic optimization for commitment and dispatch
• Directly simulate energy storage based on efficiency parameters

PSO's modeling approach is based on the use of Mixed Integer Programming (MIP) algorithms, not heuristics, and is consistent with those used by most ISO/RTOs in actual market operations. The modeling framework captures the impact that uncertainty has on operational decisions, and the important contribution that flexible resources make through their ability to respond to changing system needs. PSO's generalized design allows for flexible representation of diverse system conditions, new power system technologies, and a wide range of existing and future operating policies.