Looks like a great start. Aisles are sensible, wide curves (for H0 scale, even better if N scale), long double track run through scenery for those turbines, yard tracks seems sensible.
You might possibly want to add some crossovers between the double track mains, to increase flexibility for operations (and have the option of creating more complexity by having a section in effect being single trackby declaring part of one main out of commission temporarily, or leaving a broken down train there or something).
Also - at the bottom of the stairs, lower right - you might want to make benchwork at the end of the U here wider, and put in a viewblock between the tracks there there so you are not looking down the aisle from the bottom of the stairs, or looking out at the stairs from inside the lower U.
But it already looks great. Add scenery, and this will be a killer place to watch those turbines stretch their legs pulling longer trains.
Smile,
Stein