  An important limitation of this model is that it does not simulate changes over time in the demand for electricity, prices, technology, or other factors considered within IPM.
The model is limited by the fact that it doesn't similar change over time. 
mnli hypothesis: The model is limited by the fact that it doesn't similar change over time.  premise:   An important limitation of this model is that it does not simulate changes over time in the demand for electricity, prices, technology, or other factors considered within IPM.