Solar panels. My parents had a very early solar system, a panel that heated water directly and saved on got water bills. That was as good as you got in the 90s.
Yeah, although we knew about the photovoltaic effect for a lot longer. Edmond Becquerel discovered that effect in 1839.
The first working photovoltaic cells were created by Aleksandr Stoletov in 1888. But it took until 1954 when Bell Labs made the first practical PV cell from silicone.
It's same with fuel cells. William Grove discovered the technology in 1838 and built the first working fuel cell. But it would take until 1932 when Francis Thomas Bacon made the first practical fuel cell, which served as the base for the fuel cells NASA developed for the Gemini Project.
