Cranfield have added a "Propulsion, Power and the Environment" option to their "Thermal Power" masters courses. So that might satisfy your interest in something "green", though how much they address fuel specifically you'd have to contact SME for course details.
They also have an Avionics option in their Aerospace masters programme; again, you'd have to speak to someone at CofA to find out the details.
link to get you started
I note your profile indicates you're in N America - not sure how willing you are to consider, or practical, the travel option to the UK is.