Hi,
Here is a search result of the references to energy conservation on the Science Buddies website. If you look through them you will find links to a number of project write-ups:
https://www.sciencebuddies.org/science- ... gclmby#946
Another alternative is to go to the Project Ideas page (look at the top of the web page for the link). You can either use the project idea wizard or directly browse project ideas from that page.
Have fun!
Barrett L Tomlinson