The EIA said high RIN prices helped offset the short-lived 30 cent per gallon premium ethanol had over gasoline from December 2014 to January of this year.

"When the economics for ethanol blending may seem to be unfavourable based on spot prices, a higher RIN value reduces the "net of RIN" cost of ethanol blending," it said in a report issued Feb 23.

"As ethanol prices rose to a $0.25/gal-to-$0.30/gal premium over gasoline in December and January, prices for the 2014 D6 ethanol RIN, which can be used for RFS compliance in either 2014 or 2014, increased by roughtly the same amount, from about $0.45/gal in November to $0.71/gal in mid-January.

"This increase in the RIN value reduces the effective price of ethanol and supports ethanol blending despite the unfavorable spot ethanol pricing," the EIA said.

The agency said the gap between ethanol prices and gasoline has since narrowed. Indeed, according to today's prices for March futures, ethanol is trading at $1.38 gallon compared to $1.60 a gallon for gasoline. RINs were priced at 72 cents a gallon.

In fact, the drop in ethanol prices and increase in RIN prices have translated to savings for consumers at the pump. Based on today's prices, consumers are saving 10 cents a gallon thanks to ethanol.

The EIA also added ethanol's octane rating of 113 allows some "refiners and blnders to blend ethanol with cheaper sub-octane blendstocks to create finished gasoline, which can boldster blending margins."

Read the EIA's report here.