The brightened business outlook shows the importance of integrating petrochemicals not only with refining but also with upstream operations, according to Stephen Pryor, president of ExxonMobil Chemical Co. and vice-president of ExxonMobil Corp. A 20% surge in gas supply from unconventional resources during the past 5 years has boosted ethane production by 25% and lowered the cost of an important feedstock, Pryor told CERAWeek delegates. "We see ethane reemerging as an advantage feedstock in North America, reflecting the growing production of unconventional natural gas and the increasing importance of gas in the world energy mix," he said. In the US last year, the growing supply of relatively low-cost ethane strengthened margins for ethylene and derivatives, lightened the feed slate, and increased US exports.