Where there is genuine debate – pathways to global net zero carbon – hard-to-decarbonise sectors

I see many of the debates around responses to AGW have moved on in recent years from denial, dismissiveness and delay to focussing instead on “how to transition” and, especially, how to decarbonise the hard-to-decarbonise sectors such as aviation, heavy transport and heavy industries such as steel and cement.

Davis (2018) provides a good analysis of the main challenges and opportunities for those hard sectors, in ”Net-zero emissions energy systems”:
https://www.science.org/doi/10.1126/science.aas9793
 
from which:
“Combinations of known technologies could eliminate emissions related to all essential energy services and processes, but substantial increases in costs are an immediate barrier to avoiding emissions in each [hard-to-decarbonise] category. In some cases, innovation and deployment can be expected to reduce costs and create new options. More rapid changes may depend on coordinating operations across energy and industry sectors, which could help boost utilization rates of capital-intensive assets. In practice, this would entail systematizing and explicitly valuing many of the interconnections… , which would also mean overcoming institutional and organizational challenges in order to create new markets and ensure cooperation among regulators and disparate, riskaverse businesses. We thus suggest two parallel broad streams of R&D effort:

1. research in technologies and processes that can provide these difficult-to-decarbonize energy services, and
2. research in systems integration that would allow for the provision of these services and products in a reliable and cost-effective way.

 
… many of the challenges discussed here could be reduced by moderating demand, such as through substantial improvements in energy and materials efficiency. Particularly crucial are the rate and intensity of economic growth in developing countries and the degree to which such growth can avoid fossil-fuel energy while prioritizing human development, environmental protection, sustainability, and social equity.
Furthermore, many energy services rely on long-lived infrastructure and systems so that current investment decisions may lock in patterns of energy supply and demand (and thereby the cost of emissions reductions) for half a century to come.
The collective and reinforcing inertia of existing technologies, policies, institutions, and behavioral norms may actively inhibit innovation of emissions-free technologies…
    A successful transition to a future net-zero emissions energy system is likely to depend on the availability of vast amounts of inexpensive, emissions-free electricity; mechanisms to quickly and cheaply balance large and uncertain time-varying differences between demand and electricity generation; electrified substitutes for most fuel-using devices; alternative materials and manufacturing processes including CCS for structural materials; and carbon-neutral fuels for the parts of the economy that are not easily electrified.
The specific technologies that will be favored in future marketplaces are largely uncertain, but only a finite number of technology choices exist today for each functional role… If we want to achieve a robust, reliable, affordable, net-zero emissions energy system later this century, we must be researching, developing, demonstrating, and deploying those candidate technologies now.”
 
Also very informative and thought-provoking is Mark Jacobson’s 2021 book “100% Clean, Renewable Energy and Storage for Everything”:
https://web.stanford.edu/group/efmh/jacobson/WWSBook/WWSBook.html
 
As with Davis, Jacobson also deals with hard to decarbonise sectors.
 
I think this is a case of “perfection being the enemy of the good”.  Some resistors of transition use the lack of a perfect transition pathway to suggest the transition should be halted.

Yes, EVs have some downsides (though not as bad as ICE vehicles, all other things being equal).

Yes, unsustainability and unfairness of some mining operations in supply chains are an issue, and sustainable, fair mining should be part of the answer (but externalities of fossil energies and ICE vehicles are almost all worse than for renewable energies and EVs).

Yes, energy storage, interconnectors, deliberate overcapacity of renewables and demand management are going to require changes to infrastructure and energy management – a more complex task than with the “old” fossil-fuel-based energy systems that are gradually being replaced.

Yes, energy security has been brought into sharp relief by the global energy supply disruptions caused by the Russian invasion of Ukraine.

However, we should not halt or delay the transition to a net zero carbon global economy because of those points and related arguments.  There are reasonable, evidence-based counters to each point/argument.  We should press ahead with the transition using known tech, while at the same time researching and developing better tech which can make the transition better.  Dependence on fossil energies has been shown to present geopolitical risks as well as climate related ones.  Tackling problems of energy security and AGW are not mutually exclusive tasks.
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The stakes are too high to ease off on the transition pedal.  The costs of getting some things “wrong” during transition pale into insignificance compared with the costs of not acting swiftly enough to address AGW in time to prevent the worst-case scenarios of climate change catastrophes crystallising.