What does "with reliability consideration" mean in the context of coal/gas retirements?

In the context of coal/gas retirements, “with reliability considerations” means the ability to retire existing fossil units in the model as long as reliability is maintained.  At a high level, reliability means providing power to all customers 24x7x365 as cost effectively as possible.  

Other Stakeholder Questions and Answers

• How many zonal/nodal transmission constraints are reflected within the Dom Zone and for outside the Dom Zone?
• What is the difference between the Company load forecast and PJM’s load forecast? What is the MW amount difference per year?