Cement, steel, chemicals or ceramics are not decarbonised with slogans: they are decarbonised with energy balances, abatement curves and a plan that leaves nobody behind.
When industrial decarbonisation is discussed, the public conversation tends to simplify: electrify everything, the sooner the better. But anyone working on the plant floor knows there is a group of sectors where that recipe does not work without qualification: the so-called hard-to-abate. Cement, steel, base chemicals, ceramics, glass, paper or refining account for a large share of Spain's industrial emissions and share three characteristics that complicate everything: they need high-temperature heat, they have process emissions that do not depend on the fuel, and they operate assets with very long investment cycles exposed to international competition. The good news is that decarbonising these sectors is indeed possible. The condition is to do it with engineering, sequencing and realism, not with declarations of intent.
Why they are difficult (and why that is not an excuse)
The first obstacle is thermal. A significant part of the energy demand of these sectors is heat above 400 °C —clinker kilns at 1,450 °C, glass melting at 1,500 °C— where direct electrification still has technical or economic limits.
The second is chemical: in cement, close to two thirds of emissions come from the decarbonation of limestone, not from the fuel; no change of energy source eliminates them.
The third is financial: we are talking about assets that are renewed every 20 or 40 years, so that every investment decision taken this decade shapes mid-century emissions.
And the fourth is competitive: these are energy-intensive sectors selling into global markets, with the emissions trading scheme (Directive 2003/87/EC, EUR-Lex ETS Directive strengthened by the Fit for 55 package) European Commission Fit for 55 progressively raising the cost of every tonne emitted, and the Carbon Border Adjustment Mechanism (Regulation (EU) 2023/956) EUR-Lex CBAM , fully operational since this year 2026, redefining the rules of the game with third countries.
None of these obstacles is an excuse for not acting. They are, precisely, the reason to act with more rigour than anyone else: in a hard-to-abate sector, a badly sequenced roadmap is not merely inefficient, it is a mortgage lasting decades.
The levers, sector by sector
Our experience tells us that the starting point is always the same: measure. A complete energy and mass balance of the plant, with heat accounting by temperature level, is what makes it possible to distinguish what can be electrified, what can be recovered and what requires deeper solutions. From there, the levers fall into a fairly consistent order.
First, efficiency and waste heat recovery: it remains the cheapest MWh and the one that improves any subsequent scenario.
Second, selective electrification of low- and medium-temperature heat: industrial heat pumps up to 150-200 °C, mechanical vapour recompression (MVR) in evaporation and drying processes, resistance heating and induction where the process allows it.
Third, alternative fuels and materials: waste and biomass recovery in cement, additions that reduce the clinker factor, calcined clays.
Fourth, renewable hydrogen Green hydrogen in Spain 2026: industrial maturity and challenges where it delivers real value: direct reduction of iron ore (DRI) in steelmaking, chemical feedstock, high-temperature heat when there is no electrical alternative. And fifth, carbon capture (CCUS) for the process emissions that have no other way out, such as those from clinker.
The tool that brings order to all this is the plant's abatement cost curve (MACC): euros per tonne of CO2 avoided, lever by lever, with the interdependencies made explicit. The MACC is not an academic exercise; it is the document that allows the management committee to decide with judgement which investment comes first, which waits for the next turnaround and which depends on external infrastructure —electricity grid, hydrogen pipelines, CO2 transport— that must be demanded and planned from today.
Sequencing matters as much as technology
The most expensive mistake we see repeated is wanting to do everything at once, or the opposite: waiting for the perfect technology while the price of CO2 rises and the investment windows close. Between those two extremes there is a path: execute the mature and profitable decarbonisation levers now (efficiency, waste heat, partial electrification, renewable self-consumption), prepare the maturing ones (H2, CCUS) with engineering studies and permitting, and align it all with the natural asset renewal cycles.
Whoever anticipated five years ago what the ETS and the CBAM demand today Decarbonisation is not just sustainability it is opportunity, now decides with room to manoeuvre. Whoever did not, improvises. Active programmes such as INNOVAE INNOVAE 2026 Programme: 115 M€ for industrial efficiency open concrete windows for immediate investments Regulatory anticipation is not a luxury: it is the difference between choosing and being chosen.
And this is where the just transition comes in
Hard-to-abate sectors are not statistical abstractions: they are entire districts. A cement plant, a steelworks or a chemical complex sustain direct and indirect employment, a fabric of suppliers and territorial identity.
Decarbonising them badly —or simply closing them and importing the same product with a larger footprint— is not transition: it is emissions offshoring and industrial desertification. That is why we argue that the technical roadmap must be accompanied, from day one, by a social and territorial plan: reskilling of the workforce towards the new operations, honest dialogue with workers and public administrations, and a stakeholder map that anticipates tensions instead of managing them once they have already erupted. The social licence of a decarbonisation project is earned with the same discipline as the administrative licence.
This is, ultimately, our way of understanding the transition: there is no sustainable progress unless it is fair, and no justice is possible on top of a technically fragile project. Rigour and equity do not compete; they need each other.
How we can help
At auma we have spent more than thirty years accompanying industry at this crossroads, with a 360° view: technical, regulatory, economic and social. With the Descarbonización 360 package we build the plant's energy balance and emissions inventory, develop the abatement curve with sequenced levers, identify the available support schemes and leave behind an investment plan that is defensible before the board and before the local community. With no products to place and no technologies to sell: only independent judgement in the service of the result. If your plant is one of those having a hard time, those are exactly the ones we like to work with. Let's talk.
CTA: Request a Descarbonización 360 diagnostic session at auma or write to us at info@auma.es.