Obama didn't have an energy secretary in 2008
You're quoting (out of context) a Berkely professor who went on to be Obama's energy professor 5 months later.
I seriously doubt Obama would even in private moments discussing European style gasoline taxes without some other form of balancing tax reductions. The usual trade off here is against the social security payroll, which is a regressive tax anyway. I.e. trade a regressive tax that penalizes working for one that penalizes pollution.
You seem to think Obama has flip flopped on energy. Your whole basis for this is an off the cuff remark from a Berkeley professor. Seems like you have a Fox-news level of understanding.
