Hi,

How about using sun mirror/reflector to warm up heat sensitive metal rod.

The Metal would then turn/bend, when heated and it generates electricity by moving/rotating something.
Then once heated enough, sun light would be directed to another metal piece, which in turn does the work, while the 1st metal rod is waiting to get colder & ready to be heated again.

Of course might get more energy just using solar cells compared to that..

here you go.

http://www.amasci.com/freenrg/minto.html

needs a pully.

a very large one ;-).