Natural gas was trading at $3.66 per unit on Tuesday. This time last year, gas was trading at around $2.86.
Muchow said there also is some evidence coal sales are stabilizing, with power plants purchasing about 10 percent more coal than this time last year. Foreign markets are weaker than in 2012, however.
"It's a mixed bag," he said.
In all, West Virginia collected $273 million last month, $14.4 million below estimates.
Sales tax collections totaled $114.6 million, $4.4 million below predictions.
Corporate income taxes came in $400,000 above estimate, at $2.8 million. That's down 32 percent from last year, however.
The state collected only $77,000 in insurance premium taxes, falling far short of the estimated $3.8 million. Muchow said that drop was caused by an unusual number of people paying their taxes by the July 25 deadline.
"I guess folks were more efficient in getting the money in coffers," he said.
Although overall collections are $32.2 million short of estimates, Muchow said the numbers are not necessarily indicative of a bad budget year.
He said September is usually a better measuring stick, since quarterly income tax collections for individuals and businesses are due then.
"It's more of an indicator of where we'll be," he said.
Muchow said economic forecasts are predicting better growth in the second half of the fiscal year.