TULA, Mexico, Aug 5 (Reuters) - For at least four years, one
of Mexico's largest power plants violated an environmental
safeguard that prevents emissions of deadly pollutants,
according to documents seen by Reuters.
The Tula thermoelectric plant north of Mexico City breached
the legal limit for the amount of sulfur in the fuel oil it
burned between 2016 and 2019, according to internal documents
from the national electricity company, Comision Federal de
Electricidad (CFE), which owns and operates the plant.
The sulfur content during each of those four years -
detailed in state-run CFE's annual operations reports - was at
least 3.9%, nearly double the 2% cap set by Mexico's energy
regulatory commission for six industrial corridors, including
the Tula area.
While some Mexican environmentalists have long believed that
the plant was breaking the sulfur content rules, the CFE's
reports on plant operations that were seen by Reuters detail the
violations. The reports are not publicly available.
Reuters could not determine whether the power plant has
continued to use fuel oil containing excess sulfur this year.
Besides the high sulfur levels, the CFE documents show
another violation: emissions of sulfur dioxide, a harmful air
pollutant, are not being registered by the plant even though
that is required by law.
"The CFE shouldn't burn this fuel at 4%. The rule
establishes that it should be at 2%," said Xochitl Galvez, who
grew up near the Tula plant and is now a senator for the
opposition National Action Party.
The CFE did not respond to repeated requests for comment.
The energy regulatory commission, which is meant to enforce the
sulfur limits, also did not respond to questions.
Mexican law sets fines of between $82,000-$820,000 for
breaches of contaminant limits for fuels, including the maximum
sulfur content allowed.
When high-sulfur fuel oil is burned without
contaminant-capturing filters, massive amounts of particles and
gases are released into the air that some scientific studies
show can lead to premature death and more people developing
respiratory diseases like chronic bronchitis as well as some
Energy experts say the plant is likely operating with few or
no filters. Reuters could not independently confirm this.
The CFE did not respond to questions about premature deaths
or whether the plant uses filters.
"They must not have hardly any controls on their stacks,"
said Jonathan Dorn, an emissions expert at U.S.-based
consultancy Abt Associates, who works closely with the U.S.
Environmental Protection Agency's power plant monitoring.
He described the Tula plant's 2019 emissions levels as
The Tula plant's five chimneys belch out a steady stream of
purplish-gray smoke at all hours, easily visible from its
perimeter fence. An acrid smell fills the air, causing mild
throat irritation. Next door lies Mexican state oil company
Pemex's second-largest refinery, where the fuel oil is produced.
High sulfur fuel oil is produced by Mexico's refineries for
a number of uses besides power generation.
Pemex's press office did not respond to requests for
Some environmentalists and academics have linked emissions
from the Tula plant to chronic poor air quality in Mexico City
58 miles (94 km) away where a frequent haze has not abated
during the coronavirus lockdown despite sharply reduced traffic.
The violations at the CFE's 1,500 megawatt power plant, one
of the three biggest in Mexico, mostly predate President Andres
Manuel Lopez Obrador.
Opposition politician Galvez, along with environmental
scientists who have studied the Tula plant, said the continued
violations during 2019 reflected an ongoing dependence on fossil
fuels in Lopez Obrador's first year in government.
About 13% of Mexico's power comes from renewable sources,
mostly wind and solar, according to energy ministry data.
Lopez Obrador's office did not respond to a request for
In the past the president has said he cares about a clean
environment, while being unapologetic about the need to
prioritize domestic supplies as he seeks to wean the country off
foreign fuel imports.
His national energy plan, unveiled in June, called for
"making the most of fuel oil for electrical generation" while
taking unspecified steps to lower sulfur levels.
CFE chief Manuel Bartlett told Reuters in a May interview
that the company is committed to using cleaner energy,
especially natural gas, but that such a transition will take
time. The CFE is also looking to expand hyodroelectricity
"We want to eliminate fuel oil, but you can't do that from
one day to the next," Bartlett said.
High levels of sulfur in oil burned for power create three
especially dangerous air pollutants: sulfur dioxide, nitrogen
oxides and particulate matter smaller than 2.5 microns (PM2.5).
The CFE documents show that the Tula plant emitted 9,487
tonnes of PM2.5 in 2019. That made it the highest emitter in
North America, according to a Reuters comparison with
publicly-available U.S. and Canadian government data. The
coal-fired Shawnee power plant in Kentucky was the top U.S.
emitter, the comparison showed.
Tula's PM2.5 emissions exceeded Shawnee's by nearly 30%.
The Tennessee Valley Authority, a U.S. state-owned
enterprise that operates the Shawnee plant, did not respond to a
request for comment.
Tula emitted 14,090 tonnes of nitrogen oxides last year, the
documents showed, putting it in third place for the largest
emissions of those contaminants in North America.
Following years of public pressure in Mexico, the Tula plant
was upgraded from 2009-2016 to also use cleaner-burning natural
However, a natural gas pipeline that would supply Tula has
stalled since 2015. Nearly all of the plant's power in 2019 came
from burning 8.6 million barrels of fuel oil, the CFE documents
(Reporting by David Alire Garcia;
Editing by Daniel Flynn, Christian Plumb and Alistair Bell)