Ethane stock levels in October 2009 dropped to a 16-month low of 986,000 barrels (bbl), according to the U.S. Energy Information Administration (EIA), as a result of increased demand for ethylene. This stock level represented a 51% drop from the previous year, when the storage level was 2 million bbl.

The October stock level was down 29% from the previous month. This decreased stock level also helped increase the price of ethane at both hubs as the price rose 25% from September to October at Conway and 15% during the same timeframe at Mont Belvieu.

Although the ethane stock levels were down 26% in October, which is the most recent EIA data available, compared with May, this doesn’t accurately reflect the up and down nature the stocks experienced during that period as the plastics market experienced ebbs and flows in demand. For example, stock levels rose in both June and September as demand was down in those months.

EIA defines normal butanes as “a normally gaseous straight-chain hydrocarbon. It is a colorless paraffinic gas that boils at a temperature of 31.1ºF. It is extracted from natural gas or refinery gas streams.” – Frank Nieto