The energy security risk faced by the United States as quantified by the U.S. Chamber of Commerce fell 6.6% last year from 2011, ending a two-year run of increases, thanks mainly to oil and natural gas production from shale plays, the Chamber’s Institute for 21st Century Energy said Wednesday.

“Unlike the large recession-related drop in risk in 2009, where the improvement was for all the wrong reasons, the drop in risk in 2012 was the result of real improvements in the energy picture, many of them related in one way or another to greater unconventional oil and natural gas output,” said the Institute’s latest “Index of U.S. Energy Security Risk.”

The 2012 U.S. energy security risk score is 95.2, down from the record-high of 102 seen in 2011 but still 12 points above the average of the years 1970-1999. The 2012 score is the eighth-highest since 1970, but it breaks a two-year streak of increases (see Daily GPI, Oct. 25, 2012; Aug. 5, 2011). The index is based on a combination of 37 energy security metrics. The Institute launched the “International Index of Energy Security Risk” in 2012, which applies the same quantitative analysis used in the U.S. index to rank the top global energy users in 28 metrics.

Last year’s forecast data had predicted a 2% improvement in the 2012 index, but it underestimated improvements in unconventional oil and gas output. “Greater domestic oil and natural gas production in 2012, all of which occurred on state and private lands, was the biggest single factor contributing to the improved U.S. energy security picture in 2012,” the report said.

Of the 37 metrics in the index, 26 showed a decrease in risk while four were unchanged. The increase in domestic oil and gas supply, for example, lowered the risks to energy supply, imports, and import expenditures. Volatility in energy expenditures declined due to relatively stable energy prices, slightly lower demand and greater energy efficiency.

“Lower energy costs mean greater economic growth and a competitive edge in global markets,” the report said. Noteworthy is the expectation that by 2020 the United States would be a net exporter of natural gas. Additionally, growing oil production in the United States and Canada is shifting the global energy center of gravity from the Middle East to North America.

“It has made, for example, the removal of large quantities of Iranian oil by sanction from world markets less disruptive than it might have been,” the report said. “It has also played a role in prompting Mexico — which is seeing its oil output drop — to reconsider the prudence of its constitutional prohibition of foreign investment in the oil industry [see Daily GPI, Aug. 20; Aug. 14], and it is leading OPEC to worry that its sway over [the] world oil market is weakening [see Shale Daily, July 12].”

Separately, McKinsey & Co. partner Scott Nyquist, writing on the consulting firm’s website, seized upon the expectation that the United States could be a net exporter of energy by 2020. “It’s a significant shift in the way we think about energy security and the way we think about the impact of energy prices on our economy…The U.S. now has an abundant supply of natural gas, and this natural gas can be used in energy- and feedstock-intensive industries such as chemicals.

“We see ethylene production going up, we see polyvinyl chloride production going up, and we see fertilizer production going up. The steel industry should also benefit from cheap supplies of natural gas.”

Overall, the U.S. energy security risk index is expected to average 92.7 from 2013 through 2040, which is lower than last year’s forecast but still high by historical standards, the Chamber report said.