First Officer reported electrical failure on take off. The Flight Crew performed an air turn back and precautionary landing at the departure airport.

Narrative

During climbout; at 15;000 feet we stopped our climb due to electrical malfunctions. We made the decision to turn back towards ZZZ after suspecting a dual generator failure. The Captain's instruments were intermittently working after the failure (left side powered by inverters; right side powered by vacuum) but conditions were visual. [Priority was requested] by the flight crew after realizing that the flaps and gear would not come down. Manual extension of the gear was performed successfully and the landing was made with zero flaps. No damage was done to the airplane; and we never had a complete electrical failure. Great CRM was used; Captain was flying visually and me (First Officer) was trimming the airplane (Captain's trim was inop after the electrical malfunction); on comms and running checklists. After touching down; all of our systems came back on (flaps; Captain's instruments and his trim; etc). The cause of this is still being determined; we believe possible a loose connection or short of some sort.