Hard to Abate Industries and the Decarbonisation Challenge
Industries that are difficult to decarbonise, known as hard-to-abate industries, account for a large portion of the global carbon dioxide (CO2) emissions.
Currently, the focus of CO2 emissions reduction is aimed at developing renewable energy resources, electrifying transport systems, improving building design and producing new materials with lower carbon emissions. Unfortunately, there are a number of key emission sources which defy easy mitigation by these methods.
What are Hard to Abate Industries?
Two main areas fall under the ‘hard to abate’ banner: transportation and materials production. Hard-to-abate sectors include the likes of cement, steel, petrochemicals and aviation. These industries are major sources of emissions due to their processes and energy needs.
Transportation
Transport accounts for a fifth of global carbon emissions each year with the culprits being largely commercial i.e. aviation and shipping, both of which cannot operate readily via electrification.
Aviation: The aviation sector has a notable carbon footprint due to long-haul flights and jet fuel dependence. Sustainable aviation fuel (SAF) and better aircraft efficiency can help, but there is still a long way to go.
Shipping: The shipping industry relies on bunker fuel, a polluting type of fuel. Moving to low-carbon alternatives like green hydrogen and ammonia, as well as improving ship designs, are part of decarbonisation efforts.
Heavy-Duty Trucking: Heavy-duty vehicles produce a substantial share of road transport emissions. Electrification, hydrogen fuel cells, and low-carbon fuels are being explored as potential solutions.
Globally, these contributed about 0.95 Gt CO2/year (aviation) and 0.94 Gt CO2/year (shipping). However, the primary source of transportation emissions are light-duty vehicles, i.e., passenger cars, whose emissions stand at about 3.5 Gt CO₂/year.
Materials Production
The critical materials in this case are cement, lime and steel.
Cement Production: The production of cement releases CO2 during the calcination of limestone. While carbon capture and storage (CCS) can be used to manage emissions, finding alternative low-carbon production methods remains difficult.
Steel Production: Traditional steelmaking relies on the blast furnace-basic oxygen furnace (BF-BOF) process, which uses coking coal. Although direct reduction iron (DRI) and electric arc furnace (EAF) methods offer lower-carbon solutions, they still face challenges with energy intensity and scaling.
Chemical Industry: This sector creates a wide range of products and often uses fossil fuel-based feedstocks. Shifting to renewable energy and more carbon-efficient processes requires investment and innovation.
Production of cement and lime for use by the construction industry results in global CO2 emissions of 1.93 Gt CO2/yr. Global production of steel (with significant recycling) entails emissions of around 2.5 Gt CO2/yr.
Why These Hard to Abate Sectors Matter
These industries provide materials and services that support our way of life. For instance, cement and steel are essential for construction, petrochemicals are needed for producing plastics and chemicals, while aviation and shipping support travel and trade. Additionally, these industries are important for economic stability, providing millions of jobs globally.
Why Are Hard to Abate Industries Difficult to Decarbonise?
There are several reasons why these sectors are hard to decarbonise:
High-Temperature Processes
Many industrial processes require extreme temperatures (e.g., over 1,400°C in cement kilns and steel furnaces) and renewable energy sources often struggle to meet these requirements.
Direct Emissions from Chemical Reactions
Some emissions come from the chemical reactions themselves. For example, CO2 is released when limestone decomposes during cement production.
Dependence on Fossil Fuels
Certain processes rely on fossil fuel feedstocks, such as those in petrochemicals. Replacing these with low-carbon options involves technological advances and significant costs.
Scale of Operations
These industries operate on a large scale, so shifting to low-carbon methods will require substantial upgrades and investment.
Technical Limitations
Technologies like CCS and the use of green hydrogen show promise but are not widely viable yet due to technical, infrastructure and efficiency challenges.
Why Conventional Solutions Aren’t Enough or Suitable
Traditional renewable energy and efficiency measures are not always fitting for these sectors. High temperatures and specific feedstock needs mean that simple energy changes won’t work. These factors highlight the need for more specialised solutions.
Mitigating the CO2 Emissions of Hard to Abate Sectors
CO2 Removal from the Air
Carbon Capture and Storage (CCS)
Point source CCS captures emissions from polluting industries at the source of emissions such as power stations and large factories. The carbon dioxide is then piped or trucked away in tankers for storage or utilization. (See: What is Carbon Utilization and What is Carbon Sequestration?)
Direct Air Capture (DAC)
DAC extracts CO2 directly from the air and a DAC site does not need to be at the point of emission. This technology is promising to be particularly powerful in offsetting emissions that are hard to eliminate. (See: Advantages of Direct Air Capture)
For a more detailed analysis, see: Direct Air Capture vs Point Source
Alternative Fuels and Process Innovation
Hydrogen-Based Technologies and efuel:
Hydrogen can act as a clean energy carrier for industrial processes and fuel cell vehicles. Another example is sustainable aviation fuel (SAF) made from green hydrogen and captured CO2.
Renewable Energy Integration:
Using renewable energy to power industrial operations can cut down fossil fuel use.
Conclusion
The total emissions from the above difficult sources is 6.33 Gt CO2/yr. These numbers are not insignificant and represent around 20% of total CO2 annual emissions. With the exception of steel production, the CO2 generated by the above enterprises is directly emitted into the atmosphere.
The only reasonable way to drive these emissions to net-zero is to employ Direct Air Capture (DAC) technology.
There is no denying that decarbonising these sectors comes with technical, financial, and regulatory hurdles, however, considering the need to bring the concentration of global atmospheric CO2 back down to 350 parts per million from the current 422 ppm (see: Why Direct Air Capture), we at NEG8 Carbon strongly believe that DAC must play a key role in this endeavour.