I think this is a great tool for keeping track of 'where things seem to be at', Stuart, thanks. It is simple and clear enough for just about anyone who can understand a graph to grasp. I do hope you will make it a regular feature updated every time new data comes out.

Though there could be scope for non-OPEC production to rise a little it's beginning to look like the odds favour non-OPEC production to have plateaued. May 2005 could well have been peak non-OPEC all liquids. It has been within 2.5% below the May 2005 peak for the last two years apart from the post Katrina dip. Let's hope this plateau can be sustained for a few years more, though, with Mexico and North Sea declines looking troublesome, that may be optimistic.

The OPEC reaction does indicate they may have a small surplus of 1 to 2 mbpd that can provide for brief shortfalls but whether that is from production (and so could help with shortfall lasting several months) or just from existing stocks (hence limited to brief, occasional, shortfalls) may be a moot issue. Also, that buffer is no more than projected demand growth in 2006.

Should 'business as usual' continue it's getting mighty difficult to imagine all liquids production exceeding 90 mbpd, which current forecasts of demand project within 3 years. The 95 mbpd that EIA want for 2010 is looking like a delirious pipe dream.
http://www.eia.doe.gov/oiaf/ieo/oil.html

I guess that any significant supply disruption (greater than 1 mbpd for 3 months or more) will result in a supply shortfall...

"There must be some way out of here,"
Said the joker to the thief,
"There's too much confusion, I can't get no relief.
Businessmen, they drink my wine, plowmen dig my earth,
None of them along the line know what any of it is worth."

"No reason to get excited," the thief, he kindly spoke,
"There are many here among us who feel that life is but a joke.
But you and I, we've been through that, and this is not our fate,
So let us not talk falsely now, the hour is getting late."

All along the watchtower, princes kept the view
While all the women came and went, barefoot servants, too.

Outside in the distance a wildcat did growl,
Two riders were approaching, the wind began to howl.

The variability over the last year in OPEC production is only about 700mbpd. Whether that's a reliable estimate of spare capacity is hard to know. And as LeGorfou notes, the error bars here are unknowable. At a minimum, the difference between the IEA and EIA has to be a lower bound on the size of the error bar.
Heheh, Stuart, you came perilously close to calling me an optimist there. I'll not demur, perhaps it was today's weather - a still and pleasant day in SE England with temperatures almost as high as 10 C (50 F) even a few hours sunshine. Can I presume you are tempted to concur with my other points?

Another couple of thoughts occured to me looking at your percentage of max production graph.

  1. Both OPEC and non-OPEC production look a fairly close fit to a linear function recently running up to the Katrina blip. Non-OPEC from the beginning of 2004, OPEC from mid 2004, that might give enough datapoints to give a feel for slope and error bars.
  2. There seems to be a fairly clear negative correlation between OPEC and non-OPEC production whenever non-OPEC production is abnormally high or low, sometimes with a 1 month delay on OPEC production. That smells of there still being an OPEC buffer, albeit small, though a multitude of other explanations are possible.

"No time now for contrition:
the time for that's long past.
The walls are thin as tissue and
if I talk I'll crack the glass."
The big question is: Are the errors consistent and /or counter balancing.

If country A over reports every month and country B under reports every month, the errors may cancel out. However, the extreme consitency of the statistics from places like Venuzuala has all the marks of the EIA or IEA saying, "the figures from Venezuela are obvious nonsense" (or even "we haven't anything from them this month") "so let's use last month".

So I'd set the error bars at 2mbd or so, certainly not less. We probably will never know the exact peak, only that we will be able to say, at some time, 'we have clearly passed the peak".