The world's energy supplies are totally depleted, in the dark dystopian future - until a researcher discovers that human sexual excitement can be harnessed to create pure electrical energy. Witness the wonders of electrodes and orgasms. For science. (It's NSFW.)
The Italians have a certain flair for making bad science fiction films, as witnessed by their slew of Star Wars and Mad Max knockoffs. But their finest hour may actually be Conviene Far Bene L'Amore, known in English as The Sex Machine. Unfortunately, we weren't able to track down a copy with English subtitles, but the action is mostly self-explanatory. In the scene above, the intrepid professor figures out that his cute colleague generates a large amount of electrical energy when she's sexually aroused (more, I guess, than if she just got on a stationary bicycle and started peddling.)
Soon enough, he's able to harness the power of human sexual arousal to make a chandelier light up, brighter, and brighter, until — well, there's a reason you're supposed to wear goggles in the lab.
At last, he's able to provide some mood music during sex, by powering his record player through the sex act itself. (And yes, they still use vinyl records in the future. Of course.)
Truly a classic of the "mad sexology" genre, up there with The Curious Dr. Humpp.