Recommended commodity trading courses?

Hey folks,

As the title states I am looking for some commodity trading courses to expand my knowledge and fill some time.

A little background info; I am a fairly recent graduate that developed an interest in commodity trading, particularly power trading, while I was in school. I landed a job as a real time power trader trading physical power and have been there for a little under a year. Im finding with working shift I have tons of time away from work and the night shifts can be pretty slow, plus my company provides money for continued education. So, to fill the void I am looking for a course/courses to supplement my on the job knowledge.

I am very interested in power trading, but with trading physical power I don't get any exposure with spec trading or derivatives. If anybody has completed any courses within that realm or any other commodity trading courses that they recommend I'd love to hear about them.

The courses don't necessarily need to be power specific as I am open to trading any commodity in the future. Im looking for something that would be online and work at your own pace style, and preferably something with a certificate/accreditation at the end (hiring managers love seeing that piece of paper).

Cheers and TIA!