Hi, Here are two resources I found on the web that describe wave power or wave energy:

http://tonto.eia.doe.gov/kids/energy.cfm?page=hydropower_home-basics-k.cfm

http://ocsenergy.anl.gov/guide/wave/index.cfm

Here are some water energy science fair project ideas:
http://www.juliantrubin.com/fairprojects/renewableenergy/waterenergy.html

For more information on helping your child with science fair projects, visit this section on Education.com: http://www.education.com/topic/help-child-with-science-fair-projects/

Thanks for asking!