Hello.
I think I have decided to choose Renewable Energy as a career path. However, I’m unsure what a good major is for it. I will be attending either the University of Wisconsin or the University of Minnesota (I’m a junior). I originally had my eye on Biosystems/Bioproducts Engineering, but I hardly ever hear about it so I’m afraid it might be too undesirable for employers. I also have my eyes on Chemical Engineering, but i don’t see many people who major in that getting into Renewable Energy. I’ve also thought of Environmental Engineering, but I’ve read that most majors end up in water treatment.
(also, Wisconsin does not offer Environmental Engineering)
Any responses are appreciated 
Where are you getting your information from? Consider your sources. Just because you rarely hear about a specific major doesn’t mean it’s undesirable - biosystems engineering majors are simply uncommon; they’re not offered everywhere. That’s why you hear less on them.
“Renewable energy” is a giant field that has many workers across areas. You could major in pretty much any kind of engineering - chemical, biological, mechanical, civil, electrical - and end up working in renewable energy, partially because all of those fields have a role in it and partially because some engineering majors are relatively flexible in moving into positions. You could major in environmental science, physics, chemistry, or biology. You could also major in a variety of social sciences areas if you’re interested in how people interact and use renewable energy sources - like geography or anthropology. Political science or public policy could help you focus on energy policy; economics can intersect with environmental science to help you investigate economic impacts of renewable energy systems.
There are some majors specific to Minnesota and Wisconsin that could also easily fit - like construction management (specialize in sustainable and green buildings!); earth sciences; environmental sciences, policy, and management; astrophysics; food science or food systems; geoengineering; biology, society, and environment; manufacturing operations management; materials science and engineering; product design; statistical practice or statistical science (help come up with mathematical models and algorithms for modeling impact of renewable systems); agricultural and applied economics; atmospheric and ocean sciences; biological systems engineering; cartography and GIS; community and environmental sociology; geology and geophysics; and sustainable systems management.