Why energy intensive industries present a unique challenge

The drive towards net zero has accelerated investment in renewable energy, electrification, and low-carbon technologies across many sectors of the economy. While significant progress has been made in areas such as power generation and transport, energy intensive industries (EIIs) continue to present some of the most complex decarbonisation challenges.

Industries including steel, cement, chemicals, oil and gas, glass, and automotive manufacturing play a critical role in modern economies. They provide the materials, products, and infrastructure that underpin society, but they also account for a substantial proportion of global greenhouse gas emissions. Steel and cement production alone are responsible for approximately 14–16% of global CO₂ emissions.

The challenge arises from the nature of the industrial processes themselves. Many facilities operate continuously, often for decades, and require extremely high temperatures or energy-intensive chemical reactions. In many cases, emissions are generated not only through fuel consumption but also as an inherent part of the production process.

For engineers, the challenge is therefore not simply one of adopting new technologies. It is about delivering meaningful emissions reductions while maintaining safety, reliability, productivity, and competitiveness within the constraints of existing infrastructure and investment cycles.

 

Understanding the emissions challenge

A useful starting point is to distinguish between energy-related emissions and process emissions.

Energy-related emissions arise from the combustion of fossil fuels to generate heat or power. These emissions can, in principle, be reduced through energy efficiency measures, electrification, or the adoption of lower-carbon fuels.

Process emissions are more difficult to address because they are intrinsic to industrial production. In cement manufacturing, for example, carbon dioxide is released during the calcination of limestone. These emissions occur regardless of the source of heat used in the kiln.

This distinction is important because it highlights why no single technology can deliver deep decarbonisation across all industrial sectors. While electrification can address many energy-related emissions, it has limited impact on process emissions. Similarly, alternative fuels may reduce combustion emissions while leaving underlying chemical emissions unchanged.

A successful decarbonisation strategy therefore requires a combination of approaches tailored to the characteristics of each industry.

 

A hierarchy of decarbonisation pathways

Although every sector has unique requirements, a broad hierarchy of interventions can help guide decision-making.

Improve efficiency first

Energy efficiency remains one of the most cost-effective and immediately deployable options available to industry. Opportunities include:

• Advanced process control and optimisation
• Waste heat recovery
• Improved thermal integration
• Enhanced insulation and equipment upgrades

Many of these measures are already proven and can reduce both emissions and operating costs. However, efficiency improvements alone are unlikely to deliver the scale of reductions required to meet long-term decarbonisation objectives.

Electrify where practical

Electrification offers significant potential for reducing emissions, particularly where low and medium temperature heat is required.

Technologies such as electric boilers, heat pumps, and resistance heating are increasingly viable in a range of industrial applications. However, challenges remain for processes requiring sustained high temperatures or continuous operation.

Large-scale electrification also transfers energy demand to the power system, making the availability of reliable, low-carbon electricity a critical consideration.

Adopt lower-carbon fuels

Where direct electrification is not practical, alternative fuels may provide a pathway to lower emissions.

Hydrogen has attracted significant attention, particularly in steel production, where hydrogen-based direct reduced iron (DRI) has the potential to reduce emissions substantially compared with traditional blast furnace routes. However, its success depends on having access to affordable low-carbon hydrogen, which requires sufficient renewable electricity and the infrastructure needed to produce, transport, and store it.

Biomass and synthetic fuels may also contribute in certain applications, although questions remain regarding scalability, availability, and lifecycle emissions.

Deploy carbon capture where necessary

For sectors with significant process emissions, carbon capture, utilisation and storage (CCUS) is likely to play an important role.

This is particularly relevant in cement production, where process emissions account for a large proportion of total emissions. Carbon capture technologies can significantly reduce these emissions, although they introduce additional energy requirements and increase both capital and operational costs.

The successful deployment of CCUS also depends on the availability of transport and storage infrastructure, which often extends well beyond the boundary of an individual facility.

 

Understanding the constraints

The challenge of industrial decarbonisation is often framed in terms of technology development. However, many of the most significant barriers relate to implementation.

Several constraints influence the pace and scale of industrial transformation:

• Many industrial processes have unavoidable energy requirements, limiting how far energy consumption can be reduced.
• Electrical grid capacity may constrain widespread industrial electrification.
• Long asset lifetimes mean that industrial facilities are often designed to operate for 30–50 years or more.
• Operational reliability requirements limit the extent to which production processes can be disrupted.
• Global competitiveness places pressure on manufacturers to manage costs while investing in new technologies.

In many cases, the challenge is no longer identifying potential solutions. It is integrating those solutions into existing industrial systems in a way that remains economically and operationally viable.

 

Different industries, different pathways

The diversity of industrial processes means that decarbonisation pathways vary considerably across sectors.

Steel

Steel production is one of the most emissions-intensive manufacturing activities globally. The transition towards hydrogen-based direct reduced iron and electric arc furnaces offers a credible pathway to significant emissions reductions, although success will depend on the availability of low-carbon electricity and hydrogen at scale.

Cement

Cement production faces the additional challenge of substantial process emissions. While clinker substitution and efficiency improvements can reduce emissions, deep decarbonisation is likely to require widespread deployment of carbon capture technologies.

Chemicals

The chemical sector presents a particularly complex challenge due to the diversity of products and processes involved. Electrification, alternative feedstocks, and carbon capture all have potential roles to play, although many solutions remain at an early stage of commercial deployment.

Automotive

The automotive sector demonstrates how industrial decarbonisation increasingly extends beyond the factory gate. Although vehicle assembly operations can be progressively electrified, a significant proportion of emissions arise within supply chains, particularly through the production of steel, aluminium, and battery materials. As a result, automotive decarbonisation is closely linked to progress in other energy intensive industries.

Oil and Gas

The oil and gas sector occupies a unique position within the transition. Reducing operational emissions, including methane leakage and flaring, remains a significant priority. At the same time, the sector possesses capabilities that may prove critical to wider decarbonisation efforts, including large-scale project delivery, subsurface engineering expertise, and infrastructure relevant to hydrogen production and carbon storage.

 

Digitalisation as an enabler

While much of the discussion around industrial decarbonisation focuses on energy technologies, digitalisation also has an important role to play.

Advanced analytics, digital twins, predictive maintenance, artificial intelligence, and real-time process optimisation can help improve energy efficiency, reduce waste, and support more flexible operation.

These technologies are unlikely to eliminate emissions on their own. However, they can reduce energy demand, improve operational performance, and enhance the economic viability of broader decarbonisation programmes.

For many organisations, digitalisation may represent one of the fastest and most cost-effective routes to near-term emissions reductions.

 

Looking beyond the plant boundary

Industrial decarbonisation cannot be considered solely at the facility level.

Electrification depends on access to reliable low-carbon power. Hydrogen requires production, transport, and storage infrastructure. Carbon capture requires networks capable of transporting and permanently storing captured carbon dioxide.

This has increased interest in industrial clusters, where multiple facilities can share infrastructure and benefit from economies of scale. Such approaches may prove essential for enabling technologies that would otherwise be difficult to justify on a site-by-site basis.

The transition is therefore not simply an industrial challenge. It is a systems challenge that requires coordination across multiple sectors and stakeholders.

 

A staged transition

The scale of the challenge means that industrial decarbonisation will occur over an extended period.

In the short term, organisations are likely to focus on energy efficiency improvements, digitalisation, and targeted electrification opportunities.

Over the medium term, wider deployment of low-carbon electricity, hydrogen infrastructure, and carbon capture technologies is expected to become increasingly important.

Longer term, more fundamental changes to industrial processes and business models may be required as technologies mature and supporting infrastructure develops.

Progress is unlikely to follow a uniform path across all sectors. Different industries will move at different speeds depending on their technical, economic, and operational circumstances.

 

Conclusion

Decarbonising energy intensive industries represents one of the most significant engineering challenges of the net zero transition.

While a range of technologies are available or emerging, there is no single solution capable of addressing the diverse challenges faced across industry. Success will depend on combining efficiency improvements, electrification, alternative fuels, carbon capture, and digital technologies in ways that reflect the specific characteristics of each sector.

The challenge facing industry is no longer identifying potential decarbonisation technologies. The greater challenge is integrating them into complex industrial systems while maintaining reliability, competitiveness, and productivity.

Ultimately, progress will depend not on a single technological breakthrough, but on the coordinated deployment of multiple solutions across interconnected industries. As with many engineering challenges, success will be determined not only by innovation, but by effective implementation at scale.