Don’t forget about your energy counter! It will be necessary to upgrade it when you don’t have enough energy to open a new area or upgrade an object. It will also happen with the tech zone, which will have a certain capacity for technological improvements at your departments. Tap on their counters to have extra energy and tech supplies.

 
Your police station will start with an electricity room, but take in mind that you will need to build your tech zone to generate technology points (purple icon) on your premises. Tap on the “Management” blue button (lower-right corner buttons) and scroll down the list until you find "Resources".