I thought about using matte painting to show the outside of the city( electric grid, wind turbines, sky) to show that the city relies on producing electric energy and that it is the most important and main energy. The sky will be quite dull to give the impression that the city has been subject to war, massacre and cruel actions and that it is being dominated. The outside elements( wind turbines, electric grids) will look quite futuristic as the city is developed.
The images in the centre show the wind turbines and an electric grid which looks quite futuristic. The one in the bottom is from the animated series "Electric city" which I mentioned in my initial research, the city's main business is producing electric power using wind turbines, this is a good influence for my matte painting.
This is an initial quick thumbnail I have done just to have an idea about my matte painting which will be seen through the secret lair's window.