The new measures are part of a series of new rules being set by the agency to curb greenhouse gas (GHG) emissions. Earlier this month, it announced new rules to cut GHG emissions from coal-burning power plants and increase wind and solar power.

The latest measures as announced by the EPA yesterday will require methane emissions from oil and gas production to be cut by as much as 45 percent from 2012 levels over the next decade. 

According to a report in the New York Times, methane is 25 times more powerful than carbon dioxide in trapping heat.

While the EPA's efforts to combat rising GHG emissions should be lauded, it does make one wonder why the agency isn't as aggressive in implementing the goals of the RFS?

During the EPA's public hearing the RFS in Kansas in June, the University of Illinois said sticking to the actual RFS target for 2015 of 15 billion gallons of ethanol instead of the agency's target of 13.4 billion gallons would actually reduce an additional 4.52 million tons of CO2 equivalent (CO2e) emmissions.

This, it said using the EPA's own GHG equivalencies calculator, would amount to removing an additional 951,600 passenger vehicles from the roads this year.

It should be pointed out that CO2e includes carbon dioxide, nitrous oxide and methane.

Moreover, according to the EPA's calculator, 1,244 wind turbines would have to be installed to achieved similar GHG savings. 

The EPA often says it can't fully implement the original RFS targets - which call for higher volumes of ethanol in transportation fuel - because of the oil industry's fictitious "blend wall."

Yet, in yesterday's announcement, the EPA said its targets to cut methane emissions would cost the oil industry $420 million over the next 10 years.

If the EPA can force to the oil industry to comply with this rule - at a cost of $420 million - why won't it do the same when it comes to the RFS? 

The cost to install E15 pumps would be nowhere near $420 million especially when you consider the fact that the National Renewable Energy Laboratory (NREL) has concluded that most existing fuel dispensing infrastructure components are compatible with E15.

So while the EPA should be commended for introducing new rules to cut GHG emissions, it could make a significantly bigger impact by just sticking with and enforcing the RFS. That is, if the EPA is truly serious about reducing GHG emissions.