I would suggest something
project based. Maybe each summer something different.
I've seen (but can't link to) plans for building a
solar panel that doesn't use those photo cell thingies. (so technical, eh??) It's basically a poor man's version of a
solar panel. Or maybe those panel heaters that require a slightly open window and air flow as the panel heats up the air inside which then flows into the house to warm up the house in winter.
Recently I came across
http://www.re-nest.com/re-nest/energy-power/windbelt-the-ribbon-wind-generator-048063 It's an invention that uses wind to vibrate a ribbon/band between two magnets, and thus produces energy. Look the inventor up and you'll find something about his upgrade invention which creates
enough power to recharge a few cell phones or mp3s at once.
With something like these, one part of the project could involve learning how to store energy that's created.
And, while this isn't alternative energy related, but maybe another teacher could offer it, I, personally, think that as a culture we could use more knowledge and
experience in creating and using simple machines...and creating complex machines from simple machines. Add this ability in with some understanding of alternative energy methods, and we've got the start of some decent experimenters and re-inventors for simple needs being met without the need for stored energy use. (my opinion is that we rely too much on electric gadgets that we could get met with a little ingenuity)
Oh, or maybe explore various ways of getting light for night time reading.
Etc etc.
But yeah, primarily I would suggest something project based and that encourages experimenting and creative problem solving from the students.