AFP, published on Wednesday, April 13, 2022 at 11:23 p.m.
Faced with record inflation and in order to lower prices at gas stations, US President Joe Biden announced this week the lifting of restrictions on E15, a fuel that incorporates 15% ethanol, as well as investments in biofuels.
But these decisions are far from delighting the experts who have studied the impact of ethanol on the environment.
– What is ethanol? –
Ethanol is present in all fuels in different proportions.
The most commonly sold gasoline in the United States today contains approximately 10% ethanol (E10).
There are two types of ethanol: synthetic, derived from petroleum, and biological, bioethanol, made from wheat, sugar beets or even corn, as is mainly the case in the United States.
Cars built after 2001 can use E15, US government says
But the E15 is far from widely available. It is only distributed in 30 states out of 50, by 2,300 stations.
– What did Biden announce? –
Joe Biden announced Tuesday from the rural state of Iowa that the Environmental Protection Agency (EPA) would urgently lift a restriction that prohibited the sale of E15 in the summer (between June 1 and September 15). A restriction initially put in place over concerns about air pollution, which can be particularly problematic in the summer.
In 2018, former President Donald Trump also wanted to lift this restriction, in order to appease farmers in the midst of a trade war with China. But a judicial decision finally revoked this measure.
According to the current White House, at today’s prices, the E15 can save an average of 10 cents per gallon of gasoline (4.5 liters).
– Consequences linked to cultures –
Assessing the environmental impact of bioethanol requires including greenhouse gas emissions related to the crops required for its production.
And “the carbon footprint of ethanol compared to gasoline is not as good as originally thought,” Tyler Lark, a scientist at the University of Wisconsin-Madison, told AFP.
In 2005, the “Renewable Fuel Standard” established that an increasing volume of biofuel destined for transportation is being sold in the United States. A law was further expanded in 2007.
Result: An additional 2.8 million hectares of corn grew between 2008 and 2016, according to a study published in February in the journal PNAS.
But according to Mr. Lark, its lead author, the consequences of converting the land to corn cultivation were underestimated at the time.
“By doing this, you’re plowing up land that could potentially trap carbon dioxide,” which is released into the atmosphere, he explains.
Also, some of the fertilizer used to grow corn emits nitrous oxide (N2O), a very powerful greenhouse gas.
Thus, greenhouse gas emissions related to gasoline or ethanol are ultimately comparable, the study concludes.
Other consequences listed by the experts of the development of these crops: the contamination of water by fertilizers, or the destruction of wild habitats.
– Consequences on the exhaust pipe –
Once in the tank, bioethanol emits less CO2 per liter than traditional fuels, but more is needed.
In addition, “it produces acetaldehyde and formaldehyde, which are carcinogenic, and two of the five largest producers of ozone during photochemical fog”, which are produced mainly in the city in summer, Mark Jacobson, a professor at Stanford University, explains to AFP. .
“And ozone represents a significant health hazard, causing problems in the bronchial tubes, respiratory diseases, asthma,” he lists. According to him, both gasoline and bioethanol are “horrible”.
Ethanol is “bad for both the climate and air pollution, and spending money on it is taking away real solutions” like the electric car, concludes Mark Jacobson.