It looks like soybean-based biodiesel is returning to profitability.

This article from Biodiesel Magazine says the USDA-funded Agricultural Marketing Resource Center model shows that a hypothetical, soy biodiesel plant has reversed a six-month trend of losses and would now be operating in the black.

The overwhelming impact of soybean oil prices, which amount to close to 90 percent of the overall cost of biodiesel production, is shown in the comparison of September’s improving numbers with the poorest month, May 2009. The biodiesel revenue for that month was actually slightly higher than September at $3.10 per gallon. However, soy oil was 38 cents a gallon higher at $2.73 per gallon, natural gas remained the same at 3 cents per gallon and methanol cost was lower in May at 6 cents per gallon. AgMRC’s model plant showed a total breakeven cost per gallon, including variable and fixed costs of $3.32 for that low month of May 2009. The net return over variable costs was 4 cents per gallon in May and the net return over all costs was a negative 22 cents per gallon.

It should be noted that the model indicated negative net returns over all costs for the latter half of 2007 turning to positive in March of 2008 until March of 2009. During that year, biodiesel revenue started at $5.16 per gallon, peaked at $5.51 in June 2008 and dropped to $2.68 per gallon when the net return over all costs dropped into the red. EIA reports the spot diesel price at Chicago a year ago in October, 2008, was $2.85 cents per gallon.

The article adds that this model doesn’t tell the whole soy biodiesel story, admitting that a drop in petroleum prices has pushed regular diesel to prices significantly lower than biodiesel… if the $1 per gallon blenders tax credit is not taken off the price of a gallon of biodiesel. But the report does give hope that some of the pressure on the biodiesel industry is letting up.

You can read the report for yourself here.