Next month is the ASPO conference in Sacramento CA. Nate Hagens will be one of the speakers in the plenary (as well as on the Sunday TOD breakout panels). Here is a video of the talk he gave last year at the international ASPO VI venue in Cork Ireland. The speech covered net energy, energy properties and externalities on the supply side and addiction, relative fitness and steep discount rates from an evolutionary perspective on the demand side. Here is a link to the slides themselves, (which aren't fully shown at times on the video).