In September 2010 the last big chunk of money the Irish banks owed the bondholders, 26 billion euros, came due. Once the bondholders were paid off in full, a window of opportunity for the Irish government closed. A default of the banks now would be a default not to private investors but a bill presented directly to European governments.

http://www.vanityfair.com/business/features/2011/03/michael-lewis-ireland-201103?currentPage=all

Peak oil is not an energy crisis. It is a liquid fuel crisis.