I can assure HN that they want to be on the grid as quickly as possible. Burning half a million dollars per day in single cycle turbines will eventually cause trouble for accounting.

Running on exactly one kind of fuel is also a bit risky for a few reasons. The grid offers a significantly more diverse fuel mix. It might occasionally be more expensive, but it is also much more reliable.

The grid also offers significantly better fault handling & inertia. An order of magnitude better or more. All those aeroderivative turbines together don't make for much of a brick wall. They are quite fragile compared to what you would find in the turbine hall of a combined cycle plant. GPU load tends to be non-linear and coordinated. To the other side of a circuit it could look like a fault condition when a large cluster fires up a training batch.