Consider disaggregating generators in the public 8-bus ERCOT example

[temcdrm]

Code in ercot/bulk_system (make_case8.py, update_gen.py) will separate the aggregate generation into separate units of realistic size, but this is not currently used.

• The minimum generation is set for correspondence to one component unit, which effectively ignores the startup/shutdown costs within the aggregate
• The quadratic cost functions are not simple to disaggregate. However, the public version of this example has to linearize the cost functions anyway, so that the problem solves in Octave with GLPK. So the cost function translation may not be of concern to the public example.