b-school admission is more than just GPA and GMAT. It is more about telling a compiling story about your career progression, and aligning that with your career goal and school choice. Your career goal and it's alignment with why MBA is Europe makes a lot of sense. I would recommend thinking about the "why Oxford" part.
BTW, I think your GMAT more than offset your GPA. I remember in my application year (2010), one guy got in Oxford and INSEAD with 2.9 GPA and wrote a forum recap on his experience. You can try to search for it.
P.S. If you are not 100% set on Oxford yet, you should also looking schools with dual degree in the US like Fuqua, Yale, and Ross. Those are considered the 3 Trinity schools for MBA and energy/environment. Students places very well into renewable energy.