One feature of this year’s ASPO conference that I most enjoyed was the contradiction amongst presentations. Marcio Mello gave an animated talk on Sunday night about the pre-salt formations off the coast of Brazil quoting that there are upwards of 500 billion barrels of oil available, an extravagant estimate that peak oilers are unused to hearing. Monday morning two talks on natural gas were juxtaposed in tone and content, one claiming that natural gas is the “American Treasure” and the other claiming that shale gas is marginally profitable, let alone a “treasure.”

Contradiction in this kind of academic setting magnifies the awareness of all involved by broadening the scope of the discussion.

Every year in late summer, you will start hearing references in the media about the conversion to winter gasoline, such as the following (originally in the Bradenton Herald, but the link is long dead):

Motorists can thank a mild hurricane season in the Atlantic for the lower gas prices, according to the American Automobile Association.

Other factors include the end of the summer driving season and a cheaper winter fuel mix.

Gas stations sell a special, more expensive fuel blend during the summer to cut down on smog during hot months. Stations nationwide will start selling a less-expensive winter fuel blend Friday, which could lead to even lower prices, analysts said.

So what does this mean, and why does it make winter gasoline less expensive?

North Sea petroleum (oil+natural gas) production from 1970 to 2008 can be modeled to fit two Hubbert cycles. The first cycle represents surge production from the giant UK oil fields, Forties, Brent, Piper and Ninian. Actual cumulative production was 9937 million tonnes oil equivalent (mmtoe) 1970-2008 whilst the area beneath the two Hubbert curves is 9665 mmtoe - a difference of 2.7%.

To what extent the second Hubbert cycle will describe the decline in oil and gas production is highly pertinent but also uncertain. There are signs that the decline trajectory has already been influenced by a third cycle of giant field development with the Buzzard oil field and Ormen Lange gas field both coming on stream in 2007. The impact of this third cycle is shown below the fold.

In the first two posts in this series (1 and 2), I discussed the requirements and challenges of transitioning our global economy to renewable sources of energy. My interim conclusion was that there are serious doubts about our ability to affect any significant transition from fossil fuels to renewable energy. Much of this uncertainty is the result of uncertain systemic energy return on energy invested. In other words, when all inputs are taken into account—as must be done where we’re talking about shifting energy sources on a civilizational level—can a world powered by solar and wind power itself the way it has on oil, gas, and coal?

The key take away is precisely this uncertainty: we simply don’t know if renewables—either current or potential future technology—will be up for the job. Where does that leave us? This discussion—and many others related to Peak Oil—is really a matter of what is known as the “Precautionary Principle,” or what degree of consensus is required before we embark on a course of action that may result in irreversible harm. Because the Precautionary Principle has such broad application in discussions of Peak Oil, I’ve modeled this post as a discussion of the principle itself, using the issue of renewables transition as but one example of its application.