While industrial energy usage is diverse, it can be classified in terms of the required heat. For instance, low-temperature processes include warming up water for washing or pasteurization in the food industry, while medium-temperature applications can be found in distillation for pharmaceuticals for example. In contrast, high temperatures are needed to melt metals like iron and steel. Another important classification of industrial energy usage is intensity, that is, the sheer power of instantaneous amounts of the energy needed to be delivered. Decarbonization solutions have to be adapted to the various characteristics of these needs.
Figure 13.7 – Industrial boilers energy consumption #
A look at the evolution of energy consumption for industrial boilers (Figure 13.7) provides an overview of how most industrial heat would need to be provided across scenarios. Current needs for boilers are met by natural gas and black liquor in roughly equal shares, as well as by a smaller contribution of biomass and marginal district heating. This mix remains similar over time in REF, although the total demand increases by close to 20% by 2060. In CP30, only one change occurs in comparison with the reference scenario: natural gas rapidly decreases its contribution, shifting demand toward biomass (most of the shift occurs before 2030).
NZ scenarios show two shifts in the short term. First, before 2030, biomass also replaces natural gas, in a comparable volume in NZ60 and CP30, and more significantly in NZ50 and NZ45. Second, total energy demand is reduced, with consumption 13% to 16% lower in NZ scenarios compared with REF in 2030.
After 2030, consumption increases in all scenarios, although more slowly in net-zero scenarios, resulting in the maintenance of this initial decrease compared with REF. In other words, a large part of the difference in total demand between NZ scenarios and REF (or CP30, which presents levels similar to REF) is the result of a rapid change occurring before 2030.
On the longer term, NZ scenarios depart from REF and CP30 in other important ways as new sources contribute to further emission reductions. While black liquor maintains relatively similar levels over time, natural gas is almost entirely eliminated by 2050 and biomass is reduced significantly (with more rapid reductions in more demanding net-zero schedules). A small part of this reduction is replaced by district heating, which comes to play a small but important role in net-zero scenarios by 2040.
Hydrogen constitutes a much larger source replacing natural gas and biomass from the late 2030s. The tighter the net-zero schedule in the scenario, the quicker hydrogen increases its role, with a marginal share in NZ60 in 2040 but at 20% of the total in NZ45. On the longer term, this share converges at between 42% and 45% of the total by 2060. Although hydrogen, and to a lesser extent district heating, comes to play a dominant role in net-zero scenarios after 2040, both are completely absent in REF and CP30.
The above overview suggests that net-zero scenarios handle heat-related emissions by rapidly controlling total demand and then using fuel switching to progressively replace the most emission-intensive sources like natural gas (first) and biomass (second). This sequence also allows currently more expensive sources, such as hydrogen, to come into play later and play a significant role by 2050 and 2060.
It should also be noted that the potential contribution of waste heat recovery may be significant despite difficulties in including it in the results. This is also a source that is difficult to model given that the reuse of waste heat strongly depends on a local match between availability and needs. However, it is clear that this possibility should be studied in detail, paying special attention to how barriers to this reuse can be eliminated.