Advice on generic buildings .dae for academic use

Hello!
I teach a course in renewable energy, and my students are placing 3d models of renewable energy facilities into Google Earth as part of their final projects. I have some good 3d models for wind turbine and solar, etc. but strangely enough, I am having a hard time finding simple 3d models for generic structures, like utility scale batteries (just big rectangles the size of 2 refrigerators).

I would be so grateful if someone could point me to a (free) source for something like that. I've spent hours searching Thingiverse and similar free download sites. Ultimately, I need to convert it to a Collada (.dae) file type for import.

Many thanks for any leads!!!

John