Hard to Abate Industries and the Decarbonisation Challenge

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. However, 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 and construction. 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 high 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, 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 and Construction

Construction is accountable for 37% of the 38 billion tonnes of CO₂ that are emitted each year. For instance, the production of cement and lime for use by the construction industry results in global CO₂emissions of 1.93 Gt CO₂/yr. And the global production of steel (with significant recycling) entails emissions of around 2.5 Gt CO₂/yr.

Cement and Concrete: New methods of injecting CO₂ into the concrete where it is mineralised and permanently stored away are showing great results. Using DAC-captured CO₂ also solves the problems of (1) sourcing sustainably produced CO₂ and (2) sequestration of CO₂ that removes it from the air for good. For more details: Storing CO₂ in Concrete for Sustainable Construction

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.

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.

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. Undeniably, these numbers are not insignificant. Moreover, with the exception of steel production, the CO₂ generated by the above enterprises is directly emitted into the atmosphere.

Considering the need to bring the concentration of atmospheric CO₂ back down to 350 parts per million from the current 422 ppm (see: Why Direct Air Capture), the only reasonable way to drive these emissions to net-zero is to employ Direct Air Capture (DAC) technology. Switching to renewable energy and other such interventions are important but they won’t get the job done on their own.

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