The German Cement Industry's Transition

A Nexus of Energy, Environmental Policy, and Decarbonization Pathways

Authors: Imke Rhoden, Debapratim Mukherjee, Nargiz Ahmadova (FZJ ICE-2), Ariana Ojeda (FZJ ICE-1), Lena Fuhg (KIT IIP)

Research Importance

Cement production is an energy- and CO2-intensive process, responsible for approximately 7% of global Greenhouse Gas emissions. As a key bulk material industry, it produces 4.2 billion tonnes of cement and 14 billion m³ of concrete globally each year (Global Cement and Concrete Association (2020)).

Cement Production

  • ≈ 7%

    of Global Greenhouse Gas Emissions

  • 4.2 Billion

    Tonnes of Cement Produced Globally

A Legacy of Efficiency

The Kiln's Technological Leap:

Germany's leadership in cement production was built on groundbreaking engineering. The shift from inefficient "wet process" kilns to the highly efficient "dry process" with preheaters, pioneered in Germany in the 1950s, cut heat consumption by half and set a new global standard for the industry.

  • 1890s: Rotary kilns enable continuous production.
  • Pre-1950s: Energy-intensive wet process dominates.
  • 1950s: German-engineered preheater kilns revolutionize efficiency.
  • Today: Pre-calciner kilns are the Best Available Technology.

Declining Energy Intensity:

This technological evolution drove a steady, long-term decline in the energy required to produce a tonne of clinker. However, recent data shows this trend has plateaued as the limits of conventional efficiency are reached.

The Pollution Paradox

Clinker is a key ingredient used to produce cement, and most environmental impacts of cement manufacturing occur during clinker production. While highly efficient, clinker production remains a major source of regional air pollution. The challenge is not just what is produced, but where. Pollutants like NOx do not respect administrative borders, creating "spillover effects" that impact neighboring communities.

Modeling Spillover Effects

The Spatial Durbin Model reveals a significant relationship between clinker production and nitrogen dioxide (NO2) concentrations in Germany.  When clinker production increases by 1% in a region, the level of NO₂ pollution in that same region rises by about 0.004%. But the model shows that the pollution from clinker factories does not just stay where it is produced - it also spreads to surrounding regions.  This means that even if a region does not increase its own clinker production, a 1% rise in clinker production in neighboring areas causes local NO2 levels to increase by about 0.015%.

Blue dots on the map represent cement plants involved in clinker production. The grey shaded areas indicate regions within a 20 km radius of the cement plants. Source: Produced in QGIS based on data that we received from the Verein Deutscher Zementwerke e.V..

Source: Data based on the Global Cement and Concrete Association (GCCA) in its "Cement Industry Net Progress Report 2023."

The Pathway to Climate Neutrality

Achieving Germany's 2045 climate goals requires a radical shift. The cement industry net zero strategy involves maximizing near-term levers like clinker substitution while pioneering breakthrough technologies to tackle the unavoidable process emissions from calcination.

A multi-pronged approach is essential. Here are the key decarbonization levers:
Alternative Fuels and Biomass: Substituting fossil fuels used in cement kilns with waste materials, such as tires and biomass, to lower the carbon intensity of the energy input.
Clinker Substitution: Replacing a portion of the clinker, the most CO2-intensive component of cement, with alternative materials like fly ash, slag, or limestone to reduce emissions.
Carbon Capture, Usage, and Storage (CCUS): A technology that captures the CO2 emissions from the cement production process, preventing them from entering the atmosphere. The captured CO2 is then either stored underground or used to create new products.

Carbon Mitigation Initiatives (Energy Improvement Focus)

  • Process

    Replacing fossil fuel combustion with electrified heating technologies, powered by renewable energy sources.

  • Heat

    Improving thermal efficiency by optimizing heat exchange between process streams to minimize the need for external energy inputs.

  • Fuels

    Substituting conventional fossil fuels with low-carbon options like natural gas or carbon-neutral options like biomass and hydrogen.

A Systemic Challenge, A Collaborative Solution

The future of German clinker production requires a new industrial reality. Success hinges on a three-part strategy: continued technological innovation, a supportive policy framework with strategic funding, and critical infrastructure like CO2 transport networks. Furthermore, the evidence of spatial pollution spillovers underscores the urgent need for inter-regional collaboration to create environmental policies that are as interconnected as the air we breathe.

Technology + Policy + Collaboration = A Sustainable Future