EdX is apparently celebrating their First Birthday and as part of the celebration brough out a new range of courses
Including One on Solar Energy from Delft university.
I've done the Electronics Course provided by MIT and another to learn Python in both cases I was truely amazed at the quality of the course and as importantly the delivery
though the edX system.
If you are interested in trying it out this Autumn then take a look at what's available here.
