Ethers Resource Library

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GENERAL RESOURCES

MTBE Resource Guide
Compiled by the European Fuel Oxygenates Association (EFOA), the MTBE Resource Guide brings together factual and practical information on MTBE, including its proper use and handling.

 

Worldwide Fuels Charter (2013)
The document represents the position of vehicle and engine manufacturers from around the world in terms of fuel quality.

      • The document has a very clear position: “Where oxygenates are used, ethers are preferred. Methanol is not permitted” (emphasis added).

 

Public presentation from the President Commissioner of the Energy Regulatory Commission of Mexico
Public presentation from the President Commissioner of CRE, addressed to energy trade associations

      • “In Mexico, the most widely used oxygenate is MTBE because it permits a better oxygenation, given the characteristics of our territory and (the fact that) it does not combine with water, so it does not affect storage systems and the vehicle fleet”. (p. 38)
      • “The Worldwide Fuels Charter does not recommend the use of alcohols as fuel oxygenates, such as ethanol and methanol, and it does recommend the use of MTBE and ETBE” (emphasis in original, p.38)
      • Specific studies from EPA published in this report (Evaporative Emissions from In-use Vehicles, EPA CRC-E-77-2b, 2010) concluded that the use of (fuel) blends of up to 10% ethanol increase ozone formation (potential) by more than 600% (p. 38)

 

Response from Mexico’s Energy Regulatory Commission (CRE) to NOM-016 public consultation
Table that summarizes the official responses from CRE to inquiries during NOM-016 public consultation

      • There are “positive obtained results with the use of MTBE in the last 20 years”.

 

Análisis y Propuesta para la Introducción de Etanol Anhidro en las Gasolinas que Comercializa Pemex.
Compiled by the Intersecretarial Commission for Biofuels of Mexico (CIB, in Spanish), the document analyzes the current context of the potential ethanol market in Mexico. Some key findings include:

      • “There is no scientific evidence about environmental damages associated with MTBE that would justify to prohibit its use directly and substitute it with ethanol at any cost to the country”.

 

CRC Project No. E-65: “Fuel Permeation from Automotive Systems”
Study commissioned by California Air Resources Board to the Coordinating Research Council. It shows that the use of fuels oxygenated with 11% MTBE entail as much as 55% fewer ozone formation potential than the use of fuels oxygenated with 5.8% ethanol.

      • “The average permeation emissions with a 5.7 volume % ethanol gasoline were 1.40 grams/day higher than permeation emissions with the MTBE gasoline and 1.10 grams/day higher than permeation emissions with a non-oxygenated gasoline. This is equivalent to an average permeation emissions increase of 65% with a change from the MTBE gasoline to the ethanol gasoline and 45% with a change from the non-oxygenated gasoline to the ethanol gasoline.”

 

Note: Despite the fact that the study is from 2004, there are two key reasons why it’s still considered valid and relevant:

      • Several Latin American countries have old vehicle fleets, in which half or more of the vehicles being used are comparable to the sample used by CRC-E65 (considered representative by CRC and the California Air Resources Board in 2004).
      • In its 2014 Evaporative Emissions from On-road Vehicles in MOVES2014 report, the United States Environmental Protection Agency concludes that “ethanol was then seen to have a significant effect compared to E0 fuel (that does not contain ethanol)”. The table below, recreated from the study, summarizes the findings regarding permeation, according to the type of vehicle being used:

acela-ethanol-emissions-increaseU.S. EPA study shows increase in emissions from gas containing Ethanol

      • Besides showing increase in emissions from gasoline containing ethanol, the table shows that this effect has worsened, not improved, as the US vehicle fleet modernized.

 

 

US ETHANOL AND FOOD PRICES IN LATIN AMERICAN COUNTRIES

Biofueling hunger: How US Corn Ethanol Policy Drives Up Food Prices in Mexico
Report commissioned by ActionAidUSA to analyze the impact to Mexico of the increase in corn prices that has been driven by greater demand for US corn-based ethanol.

      • “Tortilla prices increased by 69%”
      • “The costs to Mexico of U.S. ethanol expansion since 2004 (amount) to USD $1.5 billion in the form of higher import prices”

 

The Cost to Developing Countries of U.S. Corn Ethanol Expansion
Peer-reviewed paper that discusses the impact to developing countries of the increase in corn prices due to greater demand for US ethanol

      • “Using conservative estimates from a study on ethanol and corn prices, we find that from 2006-2011 U.S. ethanol expansion cost net corn importing countries worldwide $11.6 billion in higher corn prices with more than half of that cost, $6.6 billion, borne by developing countries. Net Food Importing Developing Countries, a particularly vulnerable group, saw costs of 2.1 billion over six years. Central America experienced impacts nearly as high as Mexico’s on a per capita basis, with $368 million in higher corn import costs. Guatemala absorbed $91 million in ethanol-related costs, in part because its import dependence grew from 9% in the early 1990s to nearly 40% today.”

 

 

Air Quality

Note: MTBE, according to studies like CRC E-65 reduces polluting emissions compared to unoxygenated gasolines. Globally, ethanol is frequently compared to unoxygenated fuels—and the results show that even unoxygenated fuels would be better in many senses. Hence, MTBE is much better, in terms of air quality impacts, than ethanol.

Renewable Fuel Standard: Potential Economic and Environmental Effects of the US Biofuel Policy

US National Academy of Sciences

The National Academy of Sciences is one of the most prestigious research bodies in the world. Although they have not compared ethanol directly with ethers, it’s important to note that previous research shows that fuels oxygenated with ethers have a lower air quality impact than unoxygenated fuels.

      • “Air quality modeling suggests that production and use of ethanol as fuel to displace gasoline is likely to increase such air pollutants as particulate matter, ozone, and sulfur oxides. Published studies projected that overall production and use of ethanol will result in higher pollutant concentration for ozone and particulate matter than their gasoline counterparts on a national average.” (p.9)

Evaporative Emissions from On-road Vehicles in MOVES2014 report
United States Environmental Protection Agency
Recent report that looks at polluting emissions from a statistical perspective.

      • Ethanol was then seen to have a significant effect compared to E0 fuel (that does not contain ethanol)”. The table below, recreated from the study, summarizes the findings regarding permeation, according to the type of vehicle being used:

acela-ethanol-emissions-increaseU.S. EPA study shows increase in emissions from gas containing Ethanol

      • Besides showing increase in emissions from gasoline containing ethanol, the table shows that this effect has worsened, not improved, as the US vehicle fleet modernized.

 

Study from Stanford University
Ethanol vehicles pose significant risk to health, new study finds

      • “Ethanol is being promoted as a clean and renewable fuel that will reduce global warming and air pollution…But our results show that a high blend of ethanol poses an equal or greater risk to public health than gasoline, which already causes significant health damage.”

 

Ozone study from Stanford University
Ethanol results in higher ozone concentrations than gasoline

      • “Vehicles running on ethanol will generate higher concentrations of ozone than those using gasoline, especially in the winter, Stanford researchers have found. That could create new health concerns in areas where ozone hasn’t been a significant problem before.”

 

2011 study from the Mexican Petroleum Institute IMP
Note: the study’s methodology is only appropriate to assess impact from tailpipe emissions (not fugitive emissions), as the vehicles were not properly acclimated, according to international best practices. Hence, only the tailpipe emissions findings are reported here.

      • With 11% MTBE volume in fuels, formaldehyde emissions and acetaldehyde emissions decreased by as much as 17 and 29 percent, compared to fuels oxygenated with 6% ethanol by volume. Aldehydes, besides being carcinogenic air toxics, are also potent ozone precursors.

 

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