Natural gas traders haven’t been able to figure out where prices consistently are headed, but one thing is becoming clearer: output has remained flat for close to a year. And coal generators have a lot of power in determining prices, according to an analysis by Stephen Smith Energy Associates.

In the analyst’s latest monthly update, Smith and his team took a look what’s been going on in the domestic gas markets and reviewed onshore production levels, which have been “essentially flat” for the past nine months. Between October 2011 and this past May, gas production essentially has been unchanged, following several years of growth driven by the unconventional gas drilling boom, they said.

The gas drilling boom topped out in September 2011, but several things have supported peak gas production since:

The Smith team looked at various state gas-makers to explain how the ups-and-downs in infrastructure buildout have affected gas production trends. They also compared total rig counts for each of the five largest states, or “logical groupings of states,” such as the Marcellus/Utica shales.

“Infrastructural lags continue to be an important driver of Marcellus production growth (completions from an inventory of ‘wells waiting on completion’ and a large backlog of new gathering lines, processing plants, and major pipeline expansions),” they said. “For this reason, quarter-to-quarter changes in rig counts are particularly poor predictors of production trends.”

Meanwhile, higher gas prices have failed to sustain a spring rally. There was a cold weather and forecasters expected a hot summer, but those high temperatures in the prime cooling markets haven’t materialized, the Stephen Smith analysts noted.

“Mild weather has been part of the problem: only four of the last 15 weeks have had total degree-days higher than normal,” Smith said. The “more durable problem” has to do with gas-to-coal switching, as power generators at the $3.75/MMBtu price “tend to promptly reduce gas-fired generation in favor of coal.

“Long-term gas investors are understandably optimistic about prospects for long-term industrial and power generation demand growth, exports to Mexico and liquefied natural gas exports. But in the near-term, including the year 2014, it appears likely that weather-driven gas price rallies into the $4.00-plus range are likely to be short-lived unless the flat gas production pattern of the last year begins to show some weakness (possible, but not our most likely case),” the Stephen Smith team said.

The domestic gas storage surplus relative to 2006-2010 weekly norms fell from a surplus of 463 Bcf on Feb. 15 to “near zero” on April 26 “and it has remained near zero ever since,” Smith noted. A gas rally followed after April 26, but since then, “the sub- to near-normal degree days and near flat storage surplus: has eroded prices. A November storage peak in the neighborhood of 3,800 Bcf now appears likely.”

Both natural gas and power generation have slipped since mid-2012, while NGI’s Bidweek Henry Hub natural gas price index increased to $4.17/MMBtu in May 2013, compared with $2.03/MMBtu in May 2012.