Cement Emissions
Local cement emissions were calculated by finding the annual CO2 emissions resulting from clinker production (from Cyprus’s National Inventory of Greenhouse Gases, 2022), the annual amount of clinker produced, and using this ratio of kg CO2 vs kg clinker produced to estimate emissions for an input amount of clinker produced.
Though they are often used interchangeably, cement and concrete are very different. Concrete is the final product and it is what we use to make buildings, pavements, foundations, the list goes on…, cement is an intermediate product that is used to make concrete. In order to produce concrete, companies or individuals must mix cement with fine and coarse aggregates, like sand and gravel respectively, as well as water and optional retarding agents and other additives to strengthen the concrete.
Almost all cement used in the world is ordinary portland cement (OPC), this makes up [X]% of cement and is a main product of the local Vasilikos cement plant. This type of cement is made from the calcination of calcium carbonate to form calcium oxide. This is important because a byproduct of this process is the direct emission of CO2, and depending on the amount of calcium oxide (which is usually a major component, approximately 60%), is one of the biggest contributors of concrete & cement emissions.
CaCO3(s) CaO (s) + CO2 (g)
This process also relases significant emissions since this process happens at high temperatures and therefore needs a significant amount of either electricity or, more commonly, natural gas and coal to provide the heat for the reaction.
The ratio of mixing fine and coarse aggregates and water with cement directly affects the strength of concrete. Higher ratios of cement to aggregates and water result in higher strength concrete, with the typical mixing ratios described in the table below:
These ratios are important for calculating the emissions for different types of concrete, allowing the user to select for the type of concrete they used and get the most accurate emissions.
Imported Cement Emissions
Over the years, Cyprus has both exported and imported cement products to meet domestic demand. As the countries of import are in flux, and because distance for transport and emissions factors for production of cement of different countries varies, the emissions are calculated for specific countries & regions. The emissions were calculated by calculating the manufacturing, import, then on-island transport emissions. Manufacturing emissions were calculated using the emissions factors per tonne of cement in various countries. The import emissions were calculated by multiplying together the emissions factor of shipping lanes and the shipping distances between Cyprus and various countries using classic.searoutes.com. Then, the transport emissions were calculated assuming the concrete was purchased as ready-mixed and all aggregates and water were already mixed, then transported using a mixer-truck.
Sources:
Carbon emissions for shipping:
https://www.bsr.org/files/clean-cargo/BSR-Clean-Cargo-Emissions-Report-2020.pdf
This source allows us to compare the emissions of CO2e per Twenty foot equivalent unit which is ths
Carbon Dioxide Emissions of Cement from Different Countries:
This source allows us to compare the emissions of producing cement in different countries. This is mainly effected by the type of energy grid as well as the fuels used in cement kilns.
Sea route distance calculator:
https://classic.searoutes.com/
This invaluable resource allows us to calculate the distances for shipping cement from different countries.
Ratios of cement, aggregate, water mixing:
https://civilengdis.com/water-cement-ratio-calculation/
This source allows us to calculate the ratios in which one must mix cement to make different types of concrete.
Life Cycle Assesment of Concrete:
https://lup.lub.lu.se/luur/download?func=downloadFile&recordOId=4468239&fileOId=4469176
This source provides us with emissions factors for transporting mixed concrete in specific vehicles.
Local Cement Emissions
Locally produced cement emissions follow the same process as the imported cement emissions except it does not include the emissions from importing.