Achieving carbon-neutral cement production by 2050 through the adoption of decarbonization technologies
Creators: Clark, Garrett T
Publisher: name: University of Alberta Library
Year: 2024

<p>Global warming caused by anthropogenic greenhouse gas (GHG) emissions is leading to measurable environmental impacts that threaten to disrupt societies globally. Food and water security, human health, and economies are expected to be adversely affected. Therefore, as the world strives to reduce anthropogenic GHG emissions, hard-to-abate sectors should not be ignored. Cement, the binding agent in concrete, is extensively used in the built environment. Cement production is responsible for 8% of global GHG emissions and is the second-largest industrial emitter. Between 2015 and 2021, GHG emissions from cement production rose 15%, despite calls to mitigate climate impacts by reducing emissions. Fortunately, there are many levers by which to decarbonize cement production. Categorized, they are fuel-switching, energy-efficient technologies, alternative raw materials, alternative binders and cement chemistries, and carbon capture and sequestration (CCS). Carbonation, which is the natural uptake of carbon dioxide from the air into concrete products, is also being more widely recognized as a potential offset for GHG emissions from cement production. However, studies that explore decarbonization methods in cement production typically focus on the application of a single technology, or a small subset of technologies, missing the opportunity to compare a broad range of available technologies. Furthermore, few studies combine the impacts of all categories, thereby omitting inter-category impacts and failing to quantify the role of each category in decarbonization. This research aims to address those gaps by identifying and assessing multiple technologies within several of the decarbonization categories. Additionally, technologies from each category are combined to create carbon-neutral scenarios that explore the contribution of each category in decarbonizing the sector.</p>

<p>With Canada as a case study, energy demand and GHG emissions were modelled and validated against historical data from 1990-2019 at national and subnational levels. Technology and carbon-neutral scenarios were then evaluated from 2020-2050 and included capital costs, non-energy operating costs, energy costs, and carbon costs. For fuel-switching, transitioning to municipal solid waste or biomass in the precalciner can be done with negative GHG emission abatement costs under Canada’s current carbon price schedule. At full deployment, municipal solid waste and biomass reduce combustion GHG emissions by 39-62% annually. Hydrogen fuel and electrification of thermal energy, both transformative technologies, are not available until 2040 but reduce combustion GHG emissions from 89-98% annually when fully deployed. These results emphasize the competing demands of immediate GHG reductions and the long-term pursuit of carbon-neutral cement production. Establishing reliable, low-cost, low-carbon fuel supply chains is necessary to support fuel-switching in cement production, specifically for alternative fuels such as biomass and municipal solid waste in the short term and hydrogen in the long term. </p>

<p>An evaluation of several CCS technologies demonstrated that energy can account for as much as 81% of the total costs, eroding the benefits of capturing emissions and increasing sensitivity to energy price fluctuations. However, carbon pricing is the factor that most influences the economic benefit of carbon capture and storage technologies. Under the current carbon pricing schedule, marginal abatement costs range from -22 to 1 CAD/t CO2e, with the lowest energy demand technologies having the best economic return. A carbon price analysis shows that a minimum price of 90 CAD/t CO2e by 2030 is necessary to ensure there is at least one CCS technology with a negative abatement cost in each region.</p>

<p>Finally, energy-efficient technologies, alternative raw materials, alternative binders and chemistries and the impacts of carbonation were evaluated alongside fuel-switching and CCS technologies to establish carbon-neutral scenarios. The scenarios covered a range of possible technology mixes driven by overarching goals such as highest emissions reductions and lowest cost. The results show that carbon-neutral cement production can be achieved before 2050 with cumulative GHG reductions ranging from 199-242 Mt CO2e and marginal abatement costs ranging from -17 to -34 CAD/t CO2e at a carbon price of 170 CAD/t CO2e by 2030. Canada continues to have a higher clinker/cement ratio and lower alternative fuel consumption than other jurisdictions, meaning CCS is expected to play a larger role in reducing GHG emissions. Furthermore, carbon neutrality cannot be achieved without carbonation or a similar offset. Therefore, it is important that all cement-producing regions begin formalizing a framework to guide the calculation of carbonation impacts.</p>