Hey there dude,
I think many folks would wish to have your problem! Earning so much that they don't know if they should go to Stanford or not...
Well, forget for a second the average salaries, because I don't know how relevant that is in your case (it's also far too rough a number to be useful in any case)... if you look at the in-industry numbers, they might help you a biiiit more, but in reality what would help you most is to think about where YOU might go with your position and experience. You probably know this better than me, as you know your industry far better than I do. The question I would ask myself (and research through friends, linkedin, Internet profiles) is what do people like you do when they leave business school? Where do they go? How much do they make?
At any rate, I highly doubt that going to a top 10 program would be a waste of time. (and even a non top 10 school that is great in Energy can be fantastic). But it all depends on your goals - what knowledge you want to gain, where you want to move to, etc. etc. Who knows, maybe with a good B-school education, the next time you try and start a business, you will have more tools and more contacts to help you succeed?
But whatever the case, the network you gain in going to a school like Stanford is invaluable and incalculable even if you were to return to a similar job with a similar salary (what is the value of prestige? the social value of a top degree? the value, personal and professionals with working with the most brilliant, innovative and successful people of your generation?)
I don't really know enough about you yet to say where you might or might not get in (feel free to leave me more info, and I can advise there, if you like), but let's say for the moment that lack of volunteer work, although not fantastic is not an application-killer (like a bad education or uninteresting job might be).
Hope these thoughts help you get started, and if you have any comments, questions, disagreements, whatevers, just shoot...
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