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Decoupling environmental impacts from the energy-intensive production of cement:

the case of Aalborg Portland




Ph.D. dissertation presented by Romain Sacchi on October the 30th, 2018

About the Ph.D. project

Industrial Ph.D. financed by Danmark Innovation Fund and Aalborg Portland.

From March 2015 to July 2018.

University supervisor University co-supervisor Company supervisor
Pr. Arne Remmen Pr. Brian V. Wæhrens R&D Dir. Jesper S. Damtoft
Journal articles

Prosman E., Sacchi R. 2017. “New environmental supplier selection criteria for circular supply chains: Lessons from a consequential LCA study on waste recovery”. Journal of Cleaner Production. Vol. 172 2782:2792. Doi: 10.1016/j.jclepro.2017.11.134

Sacchi R., Ramsheva Y. 2017. “The effect of price regulation on the performances of industrial symbiosis: a case study on district heating”. International Journal of Sustainable Energy Planning and Management Vol. 14 39:56. Doi: 10.5278/ijsepm.2017.14.4

Sacchi R., Besseau R., Pérez-López P., Blanc I. 2018. “Exploring technologically, temporally and geographically-sensitive life cycle inventories for renewable energy systems: a parameterized model for wind turbines”. Renewable Energy Vol. 132 1238:1250. Doi: 10.1016/j.renene.2018.09.020

Besseau R., Sacchi R., Blanc I., Pérez-López P. 2019. “Past, present and future environmental footprint of the Danish wind turbine fleet: LCA_WIND_DK, a tool to assess and visualize the life-cycle performance of a national wind turbine fleet.”. Under review.Energy Policy.

Sacchi R. 2017. “A trade-based method for modeling supply markets in consequential LCA exemplified with Portland cement and bananas”. International Journal of Life Cycle Assessment. Vol. 23 1966:1980. Doi: 10.1007/s11367-017-1423-7

Book contribution

Sacchi R., Remmen A. 2017. “Industrial symbiosis: a practical model for physical, organizational and social interactions”. International Sustainability Stories: Enhancing Good Practices (pp. 163-181). Universidad de Sonora. ISBN: 978-607-518-250-6

Conference articles

Sacchi R., Prosman E. 2017. “A procedure to sidestep the lack of data for waste-based product systems”. 23rd SETAC Europe LCA Case Studies Symposium.

Sacchi R., Wæhrens B.; Prosman E. 2016. “Cost And Environmental Optimization Of Waste Supply Chains Using CLCA”. POMS World Conference 2016 in Production and Operations Management.

Pizzol M., Sacchi R. 2017. “Error propagation on consequential inventories: Yes We Can”. 23rd SETAC Europe LCA Case Studies Symposium.

Besseau R., Sacchi R., Pérez-Lopéz P., Blanc I. 2018. “LCA_WIND_DK: temporally, geographically and technologically-sensitive life cycle inventories for the Danish wind turbine fleet”. SETAC Europe 28th Annual Meeting, Rome, Italy.

Pizzol M., Vighi E., Sacchi R. 2018. “Challenges in Coupling Digital Payments Data and Input-output Data to Change Consumption Patterns”. Procedia CIRP. Vol 69 633:637. Doi: 10.1016/j.procir.2017.11.004

Aalborg Portland

Two million tons of grey and white cement per year

Five kilns producing white cement clinker, one kiln producing grey cement clinker

Four main cement products

Single most energy consuming activity (15% of the Danish industry annual energy budget)


BASIS RAPID LAVALKALI WHITE
High early strength, particularly suitable for pre-cast elements Suitable for ready-mix concrete Suitable for structures that may be exposed to extra aggressive environment (sulfate, alkali, etc… ) and require a long service life (e.g. bridges). High early strength and rapid hardening, suitable for exterior walls.
International group

Introductory context

The use of non-renewable fuels increases. Energy-intensive industries (EII) consume directly and indirectly (i.e., electricity and heat) 29% of the energy available every year, mostly non-renewable. [1]

Their activity is associated with 32% of the world's greenhouse gas (GHG) emissions. [2]

World energy consumption by fuel type World energy consumption by activity
Source: International Energy Agency, 2017.
The role of the cement industry

After water, concrete is the most used material in the world.[3]

But the cement sector is the second highest GHG-emitting activity within EII.
It is responsible for 7% of the world’s industrial demand for energy and for 7–8% of the world’s carbon dioxide emissions.[4]

Cement production by world region Per capita consumption of cement
Source: U.S. Geological Survey, 2018 and World Bank Data, 2018.
The production of cement

Where do GHG emissions come from?

Source: Cembureau, 2018.

Evolution of CO2 emissions intensity factor

Apparent but limited progress. Full retrofit on old equipment and state-of-the-art installations on expanding markets. Minor upgrades on older installations on mature markets.[5]

Average annual decrease of carbon dioxide emissions intensity factor for clinker of 1%, mostly from investments in energy efficient equipment.

Clinker production volume by kiln type CO2 emissions intensity per ton clinker
Source: GNR - Cement Sustainability Initiative, 2018
Policy, regulations and climate targets

The capital and energy-intensive nature of the industry seem to impede advances toward reducing GHG emissions.

But the climate targets from the Paris agreement (PA) are ambitious and suppose significant and immediate efforts.

The cement industry pledges to achieve drastic emissions reduction in line with the PA climate targets.

Cembureau roadmap 2050 IEA roadmap 2050
Source: Cembureau, 2013 and International Energy Agency, 2018
Research questions
Research question 1

What are the possibilities for a medium-size EII, such as Aalborg Portland, to reduce its environmental footprint to meet the environmental targets set for the industry?

Hypothesis one

“Industrial symbiosis and the practice of reusing by-products from other industries is compatible with and beneficial to EII operations, and such industries are often at the heart of most IS systems.”

Methods

Literature review, interviews, mass and energy balance, attributional "gate-to-gate" life cycle assessment.

Industrial symbiosis in Aalborg
Fifty years of production

Carbon footprint per ton cement, grey Carbon footprint per ton cement per MPa (28-day strength), grey
Fifty years of production

Carbon footprint per ton cement, white Carbon footprint per ton cement per MPa (28-day strength), white
Research questions
Research question 1.a

How should a significant shift in demand for secondary materials be considered from a life cycle assessment perspective?

Research question 1.b

Are there limits and/or obstacles to the extent IS and the reuse of by-products in general can help achieve more sustainable levels of operation?

Hypothesis two

“Industrial symbiosis can help EIIs, such as cement production, to reduce their environmental footprint, but a wide understanding of such systems is required in order to operate within optimal conditions without causing environmental problems elsewhere.”

Methods

Simple economic equilibrium models, hybridized life cycle assessment.

Increased supply of alternative fuels

60% and 20% of fuel substitution rate for grey and white cements (2,190 TJ).

Need to uncover the determining environmental aspects of sourcing and using combustible waste.

(access conseq_waste )

Avoids the emission of 149,000 tons of GHG.

This only holds true if the alternative fuels are sourced directly from an end-market

Sourcing combusitbel waste from non end-market may increase of emissions associated with indirect emissions from transport operations (+11%).

Recycling and incineration practices have increased over time in Europe, at the expense of landfilling.

It may be challenging in the future to source high-quality biomass-rich combustible waste.

Prosman E., Sacchi R. 2017. “New environmental supplier selection criteria for circular supply chains: Lessons from a consequential LCA study on waste recovery”. Journal of Cleaner Production. Vol. 172 2782:2792. Doi: 10.1016/j.jclepro.2017.11.134
This research has led to...

Better understanding of the interplay between combustible waste quality, price, origin and biomass content on:

  • (demand-induced) indirect emissions,
  • supply emissions,
  • pipe emissions
  • and production costs.

Better understanding of the challenges in the future: scarcity of good biomass-rich combustible waste might increase emissions associated to supply.

Recommendations

Prioritize quality of combustible waste: procurement based on calorific content and biomass content instead of mass.

Fully integrate emissions-related costs in negociations.

Develop a long-term strategy to face diminishing availability of combustible waste due to progress in recycling and composting.

Recovery of excess heat

The current excess heat supply to double by reducing the supply temperature and by recovering the excess heat from the grey cement clinker kiln.

Modeling of heat recovery potential at AP (see figure): An additional supply of 1,250 TJ of heat.

Modeling the effect of additional excess heat supply in the district heating system of Aalborg (see figure): avoiding the annual emission of 275,000 tons of GHG.

Reduce the GHG emission factor for grey and white cements by 6% and 3.5% by 2030.

It would also reduce the GHG emissions factor for one gigajoule (see figure) of distributed district heat in Aalborg by 27%.

Sacchi R., Ramsheva Y. 2017. “The effect of price regulation on the performances of industrial symbiosis: a case study on district heating”. International Journal of Sustainable Energy Planning and Management Vol. 14 39:56. Doi: 10.5278/ijsepm.2017.14.4
This research has led to...

Better understanding of how regulations, purchase price, output temperature, heat recovery and emissions displacement relate to one another.

Better understanding of the role of excess heat in diminishing the need for conventionally-produced heat. It helps to better assess its economic and environmental value.

It allows for a better dialogue with the authorities and helps promote excess heat recovery.

Recommendations

False excess heat is undesired, but current regulations lead to untapped potential. Case-by-case assessment is needed.

Supplementary cementitious materials

Substituting supplementary cementitious materials (SCM) for clinker in cement and for cement in concrete presents undeniable advantages.

Contrasted allocation methods in ALCA leads to different environmental burdens associated with SCM, such as fly ash or GGBFS (see figure).

The progressive phase out of coal power plants in Europe (see figure) may compromise the future availability of fly ash (see figure).

In a context of constrained supply, the sourcing of fly ash can displace the demand for fly ash to other SCM or even toward virgin products, thereby cancelling the benefits of clinker substitution. This calls the environmental neutrality of fly ash into question. (see figure)

Sacchi R., Prosman E. 2017. “A procedure to sidestep the lack of data for waste-based product systems”. 23rd SETAC Europe LCA Case Studies Symposium.
This research has led to...

Created a discussion between stakeholders.

Scarcity of secondary materials is increasingly considered in strategical developments.

Product development re-orients towards unconstrained SCM.

What is next?

Methodological advancement

A consistent methodology that rewards the merit of by-products use.

Decarbonizing strategy

Sustained effort to decarbonize electricity.

Electrification of industries?

Oxyfuel or post-combustion-based sequestration and storage of carbon and geopolymer cements? Yes, but high emissions abatement costs and difficulty in accessing investments, especially for small producers.

Gate-to-grave

Environmental product declarations are misused to compare cement products. Shift from mass unit to functional unit is needed when comparing cement products (e.g., "per ton per MPa", "per ton per MPa per year of durability").

A more efficient use of concrete in structures?

Conclusion
Research question 1

What are the possibilities for a medium-size EII, such as Aalborg Portland, to reduce its environmental footprint to meet the environmental targets set for the industry?

The possibilities are substantial, despite reduction previously achieved.

Industrial symbiosis and the reuse of by-products are a relevant means to achieving further emissions reduction.

Compared to 1990 levels, an overall emissions reduction of 18% and 24% per ton of grey and white cement, respectively.

In line with the roadmap projections issued by Cembureau and the International Energy Agency report. Compared to 1980 levels, the emissions reduction reaches 57% and 44% per ton per MPa of 28-day strength for grey and white cements, respectively.

The fullfilment of the Paris agreement targets depends on other industries as well.

Conclusion
Research question 1.a

How should a significant shift in demand for secondary materials be considered from a life cycle assessment perspective?

A system-wide understanding is needed if IS is to help with reducing direct GHG emissions.

This is especially relevant for by-products that are subject to high competition, such as biomass-rich alternative fuels or clinker substitutes like coal fly ash or GGBFS.

Conclusion
Research question 1.b

Are there limits and/or obstacles to the extent IS and the reuse of by-products in general can help achieve more sustainable levels of operation?

Several limitations:

  • the increasing scarcity of biomass-rich alternative fuels in Western Europe,
  • the legislation surrounding the recovery of excess heat in Denmark,
  • the limited potential of the national electricity grid to reduce its GHG emissions by 2030,
  • the unstable price development of emission allowances in Europe,
  • the increasing curve of marginal GHG emissions abatement costs, with corresponding investments not formally supported by the ETS framework.

But Economic equilibrium models rely on strong assumptions to simplify complex economic realities. And LCA suffers, for example, from uncertainties related to modeling, inventory and impacts characterization. Hybrid LCA models that focus on the use and distribution of by-products nevertheless give useful insights.

Thank you for your attention.

sacchi@plan.aau.dk

Special thanks to Jesper Sand Damtoft, Sergio Ferreiro Garzón, Zhuo Dai, Carmen Maria Batista Ruiz, Lasse Frølich, Trine Staanum, Torben Ahlmann-Laursen and Michael Rosengreen Christensen from Aalborg Portland A/S, Arne Remmen, Massimo Pizzol, Brian V. Wærhens, Ernst-Jan Prosman, Yana Ramsheva and Jannick Schmidt from Aalborg University, Romain Besseau, Paula Pérez-López and Isabelle Blanc from ParisMines Tech, as well as Denmark Innovation Fund.

Presentation in PDF-print format

Download Ph.D. dissertation

Additional material (next)

Additional material
Developing renewables in the national grid

The GHG emissions factor for Danish electricity was reduced by approximately 1 kg of CO2-eq. per kWh between 1990 and 2017. Energy-related emissions reduced by 100 kg of CO2-eq. per ton of cement (10% compared to 2017 levels).

Future GHG emission reduction is limited at least until 2030. The deployment of a local source of renewable electricity is considered instead.

Gross production electricity mix in Denmark Carbon footprint of electricity mix, excl. losses
Local renewable electricity

Five 3-MW wind turbines installed in 2020 and 2025

-> Access lca_wind_dk

Would provide 84 GWh of electricity annually

Would reduce the GHG emissions associated with electricity use by 500,000 tons of CO2-eq. over their service time.

Would reduce the GHG emissions factor per ton of cement by 1.2% for grey and white cements.

Uncertainty and variability

Epistemic uncertainty in process-based LCA (inventories, characterization methods) and stochastic variability (foreground input data). Uncertainty in equilibrium models (simplifying assumptions, based on past data)

But uncertainty struggles to be integrated (i.e., EPDs) and talked about.

Effect of epistemic and stochastic uncertainty associated to the use of alternative fuels on the carbon footprint of clinker
Pizzol M., Sacchi R. 2017. “Error propagation on consequential inventories: Yes We Can”. 23rd SETAC Europe LCA Case Studies Symposium.
Attributional vs. Consequential life cycle assessment

In this project, the distinction was clear: ALCA fit for benchmarking, CLCA fit for decision-making, with extended responsibilities.

But ALCA for benchmarking can also lead to issues: allocation with PCR for construction materials EN 15804. It can fail to provide a fair basis for choices.

GHG emissions partitioning between white clinker and recovered heat, using economic- and energy-based allocation and system expansion.