Page 25 - 2019 Sustainability Report

In assessing and targeting opportunities to achieve this time “there is no commercially viable and scalable
reductions in GHG emissions associated with cement technology to prevent or reduce the released CO ”
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operations, however, it also is important to understand from the cement manufacturing process. Instead, U.S.
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both how such products are produced and that carbon plants must focus on opportunities to use lower-carbon
dioxide (CO ) emissions are an unavoidable component fuel sources and improving energy efficiency in the
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of manufacturing cement due to the nature of the raw manufacturing process.
materials and chemical reactions involved. In fact, our GHG
footprint is largely driven by the operation of our two
cement kilns and, in particular, the calcination process that OUR INVESTMENTS IN REDUCING OUR
is chemically necessary to transform the raw materials used CARBON INTENSITY
in manufacturing cement.
We have worked hard and invested heavily in our
During the calcination process, limestone is heated in sustainability practices and improved carbon intensity
excess of 2,800 degrees Fahrenheit. This breaks down in our cement manufacturing operations, including
the molecular structure of the stone into clinker (mainly employing and improving on patented production
comprised of calcium oxide (CaO) compounds) and CO processes, upgrading equipment, improving fuel efficiency
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gas. While the solid clinker is subsequently ground and and increasing our use of lower-carbon alternative fuels
incorporated into cement, the CO is emitted from the and reducing total air emissions. In fact, since 2008, we
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plant. In a modern kiln, more than 50 percent of the Scope have invested more than $1 billion to upgrade kilns and
1 GHG emissions are a result of this calcination process, equipment at both cement plants, including replacing “wet
with the remaining emissions coming from the combustion process” cement production with modern pre-calciner
of fuels needed to heat the kiln and the on-site generation technology and installing state-of-the-art emissions control
of electricity. equipment at our Midlothian Cement Plant. We believe our
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two cement plants are now among the most modern in the
United States.
“This also places us well below the
U.S. domestic cement industry average As a result of these efforts, we have successfully reduced
intensity of 0.81 metric tonnes of CO e/ the carbon intensity of our cement business to 0.74 metric
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metric tonnes of domestic cement in 2018 tonnes of CO e/metric tonnes of domestic cement as of
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(the most recent year for which data is 2019. This also places us well below the U.S. domestic
available from the USEPA) and makes us cement industry average intensity of 0.81 metric tonnes of
one of the more carbon efficient cement CO e/metric tonnes of domestic cement in 2018 (the most
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producers in the United States.” recent year for which data is available from the USEPA)
and makes us one of the more carbon efficient cement
Cement producers have limited ability to abate or reduce producers in the United States.
process emissions resulting from calcination due to the
fundamental chemical composition of the limestone. Not surprisingly, in 2015, the company’s Midlothian
While carbon capture and storage technologies may Cement Plant was recognized by the USEPA as a high
one day be sufficiently developed to offer new, practical performing, energy efficient facility following investments
means of addressing the CO emitted from limestone, in innovative air pollution control technologies and usage
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according to the Portland Cement Association (PCA), at of alternative fuels.

Martin Marietta’s Hunter Cement Plant is outside
New Braunfels, Texas.

2 Testimony for the Congress of the United States House of Representatives Select Committee on the Climate Crisis hearing on “Solving the Climate Crisis: Reducing Industrial
Emissions Through U.S. Innovation”, September 26, 2019. Jeremy Gregory, PhD, MIT on behalf of the PCA.
PCA Response to House Select Committee on Climate Crisis dated 11/22/2019, pg. 2.
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25 / MARTIN MARIETTA / SUSTAINABILITY REPORT / 2019