Ultralow sulfur diesel with a maximum of 15 ppm sulfur is required nationwide by December 2018. Fuel regulations require 15 ppm sulfur diesel to be sold in 11 corridors, the border region and in major cities throughout 2016 and 2017. Availability of ultralow sulfur diesel in these regions—which account for 70% of the total supply—allows early deployment of clean vehicles for certain markets and uses. All gasoline sold nationwide should currently achieve an average of 30 ppm sulfur and a maximum of 80 ppm.
Fuel quality standard
Comisión Reguladora de Energía
NOM-016-CRE-2016, Especificaciones de calidad de petrolíferos
NOM-016 applies to all fuels sold in the country throughout the chain of production and supply, including gasoline (on-road, first fill, and aviation gasoline), diesel (on-road, off-road and industrial), liquid petroleum gas, fuel oil (both final and intermediate), and gasoil. The detail on technical specifications below focuses on on-road gasoline and diesel.
NOM-016-CRE-2016, published August 29, 2016, replaced NOM-086-SEMARNAT-SENER-SCFI-2005. The authority to regulate and enforce fuel quality was formally transferred to CRE in 2014 by the Ley de Hidrocarburos, Articles 78 and 79. As part of the comprehensive energy sector reform, the final section of that Hydrocarbon Law also laws out the timeline for the opening of the consumer market for refined fuels to commercial providers and requires the full transition to market-based fuel pricing by January 2018.
Originally, authority to regulate fuel quality had rested in the Secretary of Environment and Natural Resources (Secretaría de Medio Ambiente y Recursos Naturales, or SEMARNAT). In 2008, the Regulatory Law on the Petroleum Sector (Ley Reglamentaria del Artículo 27 Constitucional en el Ramo del Petróleo) conferred this authority to Secretary of Energy (SENER), with the support to be provided by SEMARNAT. NOM-086-SEMARNAT-SENER-SCFI-2005, published on 30 January 2006, modified the NOM-086-SEMARNAT-1994 (renamed from NOM-086-ECOL-1994) and fully replaced NOM-051-SEMARNAT-1993. For on-road fuels, NOM-086 set in place a timeline for sulfur reduction for gasoline and diesel fuel sold in Mexico, requiring all gasoline to meet 30 ppm average sulfur standards and diesel to meet 15 ppm maximum sulfur limits in 2009. The national oil company Petróleos Mexicanos (PEMEX), the exclusive distributor of motor vehicle fuels in Mexico at the time, achieved the requirements for premium fuel nationwide and for all fuel sold within the border region with the US, but never achieved full compliance with NOM-086.
To replace NOM-086, CRE published an emergency standard, NOM-EM-005-CRE-2015, in the Federal Register on October 30, 2015. The emergency standard took effect immediately upon publication and remained in force for a period of six months. On April 29, 2016, that standard was extended for an additional six months, the limit of application for emergency standards in Mexico. NOM-016 replaces that standard with a permanent standard, which applies to petroleum-based fuels for use by on-road and off-road vehicles, as well as jet fuel, industrial fuels. and liquid petroleum gas.
The gasoline specifications sets an annual average of 30 ppm sulfur, with a per-batch limit of 80 ppm sulfur. Diesel sulfur is required to meet 15 ppm sulfur limits for all imports and sales in the border region, three major metropolitan areas and 11 specified corridors. Diesel produced within the country and sold outside of the specified regions may still comply with a 500-ppm limit until December 31, 2018, at which point all diesel sold within the country must meet the 15-ppm sulfur limit.
Values for gasoline that impact emissions vary depending on the region, with the most stringent specifications for the Mexico City Metropolitan Region.
Table 1. Select gasoline specifications by region
|Property||Mexico City Metropolitan Region||Guadalajara & Monterrey Metropolitan Regions||Rest of the country|
|Premium and Regular||Premium||Regular|
|Aromatics (maximum % vol)||25.0||32.0||32.0||Inform|
|Olefins (maximum % vol)||10.0||11.9||12.5||Inform|
|Benzene (maximum % vol)||1.0||2.0|
|Sulfur (ppm)||30 (annual average), 80 (maximum per batch)|
|Oxygen (maximum % mass)||1.0-2.7||2.7|
The standard sets minimum limits for octane in premium and regular gasoline. While fuel providers often market higher-octane fuels, these values match the typical minimum values in the United States.
Table 2. Minimum octane limits for gasoline
|Property||Premium gasoline||Regular gasoline|
|Octane number (RON)||94||Inform|
|Octane number (MON)||Inform||82|
|Octane index ((RON+MON)/2)||91||87|
MTBE, ETBE and TAME are allowed to be added as oxygenates at levels of up to 2.7% of the oxygen mass in the gasoline. Ethanol is prohibited in the Mexico City, Guadalajara and Monterrey Metropolitan Areas. In the rest of the country it can be added to make up up to 5.8% by volume of the finished fuel. There are no waivers for vapor pressure limits due for ethanol use.
Vapor pressure impacts the evaporative emissions from vehicles, service stations and during refueling. The specifications for vapor pressure and volatility vary depending on the altitude and climate of the region. Specific volatility classes are defined in the regulation.
Table 3. Specifications for vapor pressure and distillation temperature by volatility class
|Vapor pressure||kPa (lb/in2)||54 (7.8)||62 (9.0)||69 (10.0)||79 (11.5)|
Final boil (Maximum)
|Distillation residue (maximum)||% Volume||2||2||2||2|
And vapor lock protections are defined for each volatility class.
Table 4. Specification for protection against vapor lock
|Minimum temperature (°C) to create a vapor/liquid ratio equal to 20||Volatility Class||1||2||3|
|A, B, C||54||50||47|
For each region and season or month, a specification is set for the fuel to meet certain volatility classes and vapor lock protections, defined in Table 5.
Table 5. Seasonal requirements for each region
|Season||Metropolitan Regions of Mexico City and Guadalajara||South, Central and Pacific States||Northern States and Monterrey Metropolitan Region|
|Summer (June-August)||AA-2 (June)
AA-3 (July & August)
 Includes the states of Veracruz, Campeche, Puebla, Tabasco, Yucatán, Quintana Roo, Aguascalientes, Jalisco, Guanajuato, Michoacán, Zacatecas, Morelos, Tlaxcala, Estado de México, Hidalgo, Querétaro, Baja California, Baja California Sur, Sonora, Sinaloa, Nayarit, Colima, Guerrero Oaxaca, and Chiapas.
 Includes the states of Nuevo León, Chihuahua, Durango, Coahuila, Tamaulipas, and San Luis Potosí
Diesel sulfur specifications are defined in Table 6.
Table 6. Implementation timeline for sulfur reduction in diesel fuel
|Implementation timeline||On-Road Diesel||Agricultural and marine diesel|
|Specified metropolitan regions, freight corridors, and border region||Rest of country|
|Upon adoption||15 ppm||500 ppm||500 ppm|
|December 31, 2018||15 ppm||15 ppm||500 ppm|
Other parameters of importance to vehicle manufacturers, some with limited impact on emissions, include cetane, aromatics and lubricity (Table 7). Because desulfurization processes tend to result in improved cetane levels, the actual fuel quality has far exceeded equivalent limits in the US and is expected to exceed the minimum specification in Mexico without additional effort by refiners. Desulfurization has the opposite impact on lubricity, but the fuel specification in the U.S. matches the proposal here.
Table 7. Select diesel specifications for on-road, agricultural and marine diesel
|Cetane (minimum index and number)||45|
|Aromatics (maximum % vol)||35|
|Lubricity (maximum microns)||520|
Intermediate Fuel Oil (IFO)
The IFO sulfur specifications meet current International Maritime Organization (IMO) standards for use in international shipping. Mexico is working towards the ratification of the IMO MARPOL Annex VI agreement which establishes more stringent provisions for air quality protection and is planning to seek Emission Control Area (ECA) designation under MARPOL Annex VI (once ratified). ECAs require more stringent regulations for fuel sulfur content and NOx emissions compared to those established by IMO. If implemented, intermediate fuel oil (IFO) used within the ECA should not exceed 0.1% sulfur, although fuel of that quality will not necessarily need to be sold within Mexico.
Table 8. Maximum sulfur limits for IFO
|IFO-180 (% mass)||3.5|
|IFO-380 (% mass)||3.5|