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SWith all the shifts that occurred, light
product yields rose very slightly, and residual fuel yields only increased
0.5 percent.
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SPart of
this was due to the ability of these refiners to increase their use of
conversion capacity slightly during the shoulder months. In addition, as just described, refiners’
use of crude oils is not simple, and complex refiners, such as those we have
in the U.S., do have a fair degree of flexibility that they exercise by being
able to use a wide range of crude oil feeds.
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SWe also looked at 8 sweet crude oil
refineries (on both the Gulf Coast, Midwest, and East Coast),
representing almost 2 million barrels per day of refinery inputs. In this case, we saw some increase in the
use of heavy and intermediate sweet crude oils in place of the light sweet
crude oils. But again, we saw only a
slight decline in gasoline yield, which may have been due to increased MTBE
bans this year as well as the crude oil quality shift. Residual yield stayed at about the same
level.
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SThe U.S. examples tell us that a) complex
refineries have more flexibility to use heavy sour crude oils than the simple
conversion capacity limitation theory would imply and b) U.S. complex
refineries had enough flexibility to both use more heavy sour as the
economics improved, but also to do so without much residual yield penalty.
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SThese examples have been for the U.S., where
we have detailed data. But the U.S.
has the most complex refinery system in the world. What about the rest of the world?
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