The federal requirement to blend ethanol into gasoline on the theory that it will reduce the hypothetical global warming that hasn’t appeared yet has been a joke from the start. By adding a huge amount of demand for corn, it did push up prices for that commodity, and made vast swaths of the rural Midwest prosperous, though it has injured poor Mexicans and others who depend on corn for a substantial portion of their nutrition and driven up the rice of feed used for animals, raising meat prices.

The net energy balance of ethanol production – subtracting the amount of energy necessary to grow he corn, transport it to refineries, and then transport the ethanol to gasoline producers has been controversial. But owing to improvements in cultivation techniques (which have caused increased agricultural runoff – see below), the US Department of Agriculture estimated in 2015 that the balance is positive:

Ethanol made the transition from an energy sink, to a moderate net energy gain in the 1990s, and to a substantial net energy gain by 2008.

Unlike oil, which is produced in large amounts at the wellhead, corn production is widely dispersed, so pipelines can't be used to transport it. Corn is trucked to the ethanol refinery, and then the ethanol is normally shipped in tank cars to oil refineries, where it is blended into gasoline. All of this transportation uses energy and imposes a cost from accidents, including derailments. Pipelines are more efficient and safer.

Now, the EPA has finally issued a new report, one that it is requited to issue every 3 years but which has been delayed by 4 years, and admits that the ethanol mandate comes at a considerable environmental cost. The Public News Service summarizes:

Federal law requires the EPA to assess the environmental impact of the fuel standard every three years, but the new report, issued in July, was four years overdue. According to David DeGennaro with the National Wildlife Federation, the report documents millions of acres of wildlife habitat lost to ethanol crop production, increased nutrient pollution in waterways and air emissions and side effects worse than the gasoline the ethanol is replacing.
"In finding that the Renewable Fuel Standard is having negative consequences to a whole suite of environmental indicators,” DeGennaro said, “the report is a red flag warning us that we need to reconsider the mandate's scope and its focus on first-generation fuels made from food crops.” 

Jaz Shaw points out at Hot Air:

Some of the negative effects aren’t specific to ethanol, such as the loss of wildlife habitat from expanded corn production. That would happen no matter what you were growing or building in formerly forested areas. But the increased runoff of nutrients and chemicals used in this type of farming are impacting water supplies far beyond anything caused by the occasional oil spill from a tanker car or pipeline.

The bigger surprise is the fact that ethanol production and combustion significantly increases the production of nitrous oxides (Nox). This combines with oxygen in the atmosphere when exposed to sunlight, producing ozone. Now, when we have ozone far up in the atmosphere it helps shield the planet from the sun’s natural radiation, which is a good thing. But ground-level ozone produces no such benefit and actually contributes to the formation of smog and leads to respiratory ailments for many people.

Those vehicles that feature cuddly images like a new leaf and righteously proclaim themselves to be “flex fuel vehicles” are actually aggravating some people’s respiratory problems, far more than gasoline powered vehicles.

Photo credit: Jeff Egnaczyk via Flickr

None of this speaks to the excessive costs that ethanol forces on drivers and auto manufacturers.

Alas, the mandate is so popular with corn farmers in Iowa, home of the first round of presidential nominations, that President Trump (and other politicians) that they not only maintain the mandate, President Trump just last week “told an audience in Iowa that he was "very close" to having EPA issue a waiver to the Clean Air Act to allow year-round sale of E-15.”

The madness continues.