Laying the concrete foundations for Cement

photo-1527721145931-6820fa5d4048 Credit: Unsplash

The production and use of cement are responsible for approximately 5% of global greenhouse gas emissions, with some estimations setting the total to be closer to 8% of total emissions[i]. This is greater than the climate impact of air travel, though one could argue that building homes and dams is less frivolous than intercontinental travel[ii]. CO2 emissions from the cement industry in Europe peaked in 2007 with 173.6 Mt CO2, approximately equivalent to the climate impact of the Netherlands[iii].

Screen Shot 2019-03-18 at 11.58.34 Global cement and fossil energy production to 2016 Credit: USGS, 2014; Mohr et al., 2015

Based on a cement plant with modern technology and equipment the production of a tonne of cement results in 0.65 to 0.92 tonnes of CO2 . Of this ~60% of the CO2 comes from the calcination process, while the rest (~40%) is produced during the use of fossil fuels[iv]. In Germany, clinker production, the primary component of cement, is amounted to 32 million tonnes produced in 2014.[v]There are approximately 356 cement production installations in Europe.[vi]

Concrete is the most consumed material on earth, second only to water, with three tonnes per year used for every person. Twice as much concrete is used in construction as all other building materials combined.[vii]

Inputs

Limestone is the major resource required when making cements. A common grey coloured rock that is formed naturally from ancient shells of sea creatures, limestone contains calcium that when processed becomes a cementitious material. As a result, cement factories are generally located close to a limestone quarry. The second major input is energy required in the limestone conversion process. In Europe this energy comes primarily from waste, natural gas or, in some cases, coal. Other inputs include clays, blastfurnace slag and natural pozzolanic materials.

Screen Shot 2019-03-15 at 14.35.57 Credit: Bellona

A building block of our society

Cement is used in construction to make concrete as well as mortar and to secure infrastructure by binding the building blocks. Concrete is the second most consumed material in the world after water. Concrete is used in almost all residential and commercial construction types, for example making up 3.6% of the total cost of a single detached wood frame house or 9.8% of a cast concrete frame multi-dwelling building.[viii] Although a variety of low energy construction methods exist, the cement sector argues that the use of concrete in buildings can add to “thermal mass” increasing structural thermal energy storage and flexibility by offsetting peaks in electricity demand.[ix]

The intensity of concrete use in the electricity supply sector is anticipated to increase. Decentralised low carbon electricity generation, particularly in the form of on- and offshore wind generation, will require concrete for stabilising foundations. Large public works and infrastructure with long service horizons can be concrete intensive. Dams for electricity, irrigation and potable water, coastal flood defences, drainage systems, and transport infrastructure have traditionally been dependent on concrete as a core constituent.

Find out more about the process of the cement industry and its potential to decarbonize in our report “An Industry’s Guide to Climate Action”

[i] R. Andrew, “Global CO2 emissions from cement production,” Earth System. Science Data, pp. 195-217, 2018.

[ii]A. Murphy, “Aviation emissions and the Paris agreemnet,” Transport & Enviroment , Brussels, 2016.

[iii]Moya, Pardo and Mercier, “Energy Efficiency and CO2 Emissions: Prospective Scenarios for the Cement Industry,” JRC, 2010.

[iv] Ibid.

[v] USGS, “2014 Minerals Yearbook Germany,” USGS, 2014

[vi] DG Growth, “Cement and Lime,” 2017. [Online]. Available: https://ec.europa.eu/growth/sectors/ raw-materials/industries/non-metals/cement-lime_en .

[vii] Cement Industry Federation, http://www.cement.org.au/AboutCement.aspx

[viii] J. Rootzén and F. Johnsson, “Managing the costs of CO2 abatement in the cement industery,” Climate Policy, 2016.

[ix] 3E, “Structural thermal energy storage in heavy weight buildings – analysis and recommendations to provide flexibility to the electricity grid,” CEMBUREAU – The European Cement Association ASBL, Brussels, 2016

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