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Climate Action Epistemology Part 4: Technological Potential in the IPCC Mitigation Report

April 12, 2023

Ed. note: You can find Parts 1, 2, and 3 of this series on here, here, and here.

Despite the IPCC report broadening its focus by including a chapter on demand management, the rest of its chapters primarily explore technological means of addressing the climate crisis. When climate mitigation literature maintains such an emphasis, it’s not surprising that many see decarbonization as purely an engineering issue. By examining the IPCC report’s discussion of mitigation technologies, we can learn what messages the academic community is sending to the public about the difficulty of the transition from fossil fuels to renewable energy.

Chapter six summarizes research on the topic of “energy systems,” and it may be easiest to begin our examination at the end of that chapter. That’s where the authors highlight a couple of frequently asked questions that should directly address what they want lay readers to take away about technological potential. “Will energy systems that emit little or no CO2 be different than those of today?” asks the first question. The authors respond that “Low-carbon energy systems will be similar to those of today in that they will provide many of the same services . . . But future energy systems may be different in that people may also demand new services that aren’t foreseen today.” We’ll start using electricity for services like light-duty transport, heating, and cooking, and incorporate other types of energy carriers for sectors that are harder to electrify. Thus “Electricity, hydrogen, and bioenergy will be used in many situations where fossil fuels are used today,” and “almost all electricity will be produced from sources that emit little or no CO2.” Fossil fuel consumption will be reduced substantially. “All of these changes may require new policies, institutions, and even new ways for people to live their lives.”

The second frequently asked question is “Can renewable sources provide all the energy needed for energy systems that emit little or no CO2?” The authors answer that the energy available from natural sources like the sun and the wind “exceeds the world’s current and future energy needs many times.” However, “that does not mean that renewable sources will provide all energy in future low-carbon energy systems,” for several reasons. They explain that some countries with fewer renewable energy resources may use more nuclear power and fossil fuel plants with carbon capture and storage; or the variability of certain sources like wind and solar may be supplemented by more controllable options; or limits on certain renewable resources might be established to manage undesirable trade-offs like increased mining and biodiversity loss.

The answers provided for these two questions give only the faintest hint of any difficulty involved in transitioning to an all-renewable energy system. There is no indication that any services might be curtailed. In the future, the main difference is that we may enjoy additional services. The authors suggest that electricity, hydrogen, and bioenergy will successfully replace fossil fuels. And when discussing why some countries may not go 100% renewable, they don’t mention any serious obstacles to the transition. All the energy that we expect will be there, from one source or another. After all, there is far more than enough renewable energy available to meet humanity’s growing energy demands.

The idea of renewables’ overabundance appears repeatedly throughout chapter six. The amount of sunlight that reaches the Earth’s surface continuously is “almost 10,000 times average world energy consumption.” Recent estimates of “potentially exploitable” wind energy amount to “20-30 times the 2017 global electricity demand.” The theoretical amount of hydropower potential globally exceeds total electricity production in 2018. “The geophysical potential of geothermal resources is 1.3 to 13 times the global electricity demand in 2019.” And “wave energy alone could meet all global energy demand.” The general picture is a world awash in harnessable energy—far more than we need today or in the future.

But for those who continue reading past the astounding theoretical potential of these energy sources, another pattern arises. As various limits are factored in, the potentials shrink significantly. Accounting for “competition for land-use” drops solar energy’s availability from 10,000 times the world’s energy consumption down to “roughly double” that amount. That may appear inconsequential to the reader, since any amount larger than today’s energy consumption, from just one source of renewable energy, seems to suggest plenty of availability. But it’s vital to recognize how much solar energy potential was subtracted from its theoretical maximum after accounting for one limit. In reality, we live within layers of limits. A paper by Floyd et al. observes that “the proportion of [renewable energy’s] theoretical potential that can be realised in practice, once the broad spectrum of geographical, technical, engineering, environmental, economic and socio-political factors is taken into account, is far less certain – though certainly orders of magnitude less than theoretical potential in absolute scale.”

Indeed, the picture of unlimited energy painted above and the relatively straightforward vision of the energy transition expressed in the FAQ contrasts with much of the commentary throughout chapter six, which is more critical:

  • The report states that “it will be challenging to supply the entire energy system with renewable energy . . . Economic, regulatory, social, and operational challenges increase with higher shares of renewable electricity and energy. The ability to overcome these challenges in practice is not fully understood.”
  • As a result of these potential barriers, fossil fuels are projected to maintain a significant ongoing presence in our primary energy mix. “In scenarios limiting warming to 1.5°C (>50%) with limited or no overshoot, fossil energy provides 59-69% (interquartile range) primary energy in 2030 and 25-40% primary energy in 2050 (AR6 Scenarios Database). In scenarios limiting warming to 2°C (>67%) with action starting in 2020, fossil energy provides 71-75% (interquartile range) primary energy in 2030 and 41-57% primary energy in 2050 (AR6 Scenarios Database).” Those scenarios imply a huge reliance on carbon capture and storage (CCS) to prevent fossil fuel emissions from reaching the atmosphere, but our ability to implement large-scale CCS is unproven. By 2100, non-biomass renewables account for just 52% of primary energy in these scenarios, “even with stringent emissions reductions targets and optimistic assumptions about future cost reductions.”
  • And then there are several major sectors of the economy that may be difficult to maintain in an all-renewable world, at least at today’s scale. “CO2 emissions from some energy services are expected to be particularly difficult to cost-effectively avoid, among them: aviation; long-distance freight by ships; process emissions from cement and steel production; high-temperature heat (e.g., >1000°C); and electricity reliability in systems with high penetration of variable renewable energy sources. The literature focused on these services and sectors is growing, but remains limited, and provides minimal guidance on the most promising or attractive technological options and systems for avoiding these sectors’ emissions. Technological solutions do exist, but those mentioned in the literature are prohibitively expensive, exist only at an early stage, and/or are subject to much broader concerns about sustainability (e.g., biofuels).”
  • In a world powered in large part by intermittent renewables like wind and solar, our ability to store energy for when it’s needed will become extremely important. However, of the 10 storage technologies considered in the report, only three are said to be potentially appropriate for seasonal storage, all of which are designated as “low” maturity. This raises questions about how we’ll deal with periods of weeks or months when sunlight and wind happen to be harder to come by.

As we can see, the takeaways around technological potential could be very different based on the parts of the report one focuses on. But the serious challenges highlighted in the points above are not well-represented in the FAQs that summarize the content in chapter six. Though the chapter begins with a restatement of the feasibility dimensions used in the report to assess each type of energy technology, the discussion often gives the impression that any issues are overall pretty minor and won’t prevent the creation of an all-renewable energy system that operates like the current one.

One interesting point in the chapter is a brief discussion of the “energy return on investment” of fossil fuels. It’s a ratio of how much energy society gets back for each unit of energy invested in setting up the generating system, an important concept we can use to compare different sources of energy. Sources with an energy return ratio of 1:1 don’t produce any energy surplus, and modern industrial societies have been built around fossil fuels with a return currently around 30:1. “The energy return [on] investment (EROI) is a useful indicator of full fossil lifecycle costs,” the authors write. “Fossil fuels create significantly more energy per unit [of] energy invested – or in other words have much larger EROI –than most cleaner fuels such as biomass or electrolysis-derived hydrogen, where intensive processing reduces EROI.” Recall that the authors assert in the FAQ that biomass and hydrogen will play a major role in replacing fossil fuels for various services, like long-distance transport. But the EROI of some biomass, for example, may hover close to 1:1, meaning that it wouldn’t offer much usable energy and may never be used on a large scale for that reason alone. As the EROI of society’s main sources of energy drop, so does the prospect of energy abundance.

Strangely, the IPCC’s authors don’t discuss the EROI of the main sources of renewable energy like solar and wind. Some studies have suggested lower EROI values for these resources than what fossil fuels have historically provided, though others contest that idea. Calculating EROI isn’t a perfectly straightforward process, as different boundaries are used in the literature and debate is ongoing. But if we take EROI figures as a rough estimate, it is possible that an all-renewable energy system would offer less usable energy than a fossil-fueled one.

Another complication arises from the fact that the energy transition will rely on fossil fuels at least in its early stages. As we’ve moved in recent years from more abundant to harder-to-obtain sources, these fuels’ EROI is decreasing, and that will feed through to our transition efforts. Even if renewables ultimately provide as much or more energy than fossil fuels, energy could become scarcer during the transition. A cap on fossil fuel-derived energy would also likely cap economic growth, and would require us to adapt to energy limits we haven’t ever had to face. None of these possibilities are mentioned in the discussion.

The more we improve existing technologies, reduce their costs, and bring nearly mature options to scale, the faster we’ll be able to transition to an all-renewable world. The IPCC report examines the forces involved in this innovation process in chapter 16. However, significant contradictions arise in the analysis. The authors repeatedly observe that countries’ interest in gaining competitive advantages is a driver of technological development, but also note that cooperation is a necessary component. Solar panels are spotlighted as a product of collaboration. “No single country persisted in developing solar photovoltaic (PV): five countries each made a distinct contribution, with each leader relinquishing its lead. The free flow of ideas, people, machines, finance, and products across countries explains the success of solar PVs. Barriers to knowledge flow delay innovation.” Today, the transition to a new energy system based on increasingly complex technologies “requires cooperation.”

Another contradiction arises from countries’ desire to develop new technologies in order to stimulate economic growth, which is a primary driver of emissions and environmental degradation. “Technological change and innovation are considered key drivers of economic growth and social progress. Increased production and consumption of goods and services creates economic benefits through higher demands for improved technologies. Since the Industrial Revolution, however, and notwithstanding the benefits, this production and consumption trend and the technological changes associated with it have also come at the cost of long-term damage to the life support systems of our planet.”

The authors do not deeply examine the implications of these contradictions during their review. But it seems clear that past dynamics around technological innovation cannot continue into the future if we’re to address the climate crisis. We’ll only reduce emissions globally if countries reject possible competitive advantages and cooperate towards a rapid energy transition. They must also not pursue innovation only on the condition that it boosts economic activity and consumption. We’ll need to establish limits to economic growth to ensure that new technologies that generate energy and make our resource use more efficient actually reduce our impact on the environment rather than increasing it.

The IPCC report could go deeper into the feasibility analysis for different sources of energy and broaden the metrics used to compare them. The authors don’t really level with the reader about just how challenging some options may be to implement, and consequently how we should plan for the energy transition. They do assert, however, that “Policy approaches facing deep uncertainty must protect against and/or prepare for unforeseeable developments,” including by “planning for the worst possible case or future situation.” Despite suggestions of energy abundance and a seemingly straightforward transition, “This uncertainty extends to the impacts of low carbon innovations on energy demand and other variables, where unanticipated and unintended outcomes are the norm.”

There is good reason to expect that the transition process will be more difficult than we tend to hear about, and that technological solutions, while essential, aren’t enough to address the climate crisis. Chapter 16 reminds us that “Underlying driving forces of the problem, such as more resource-intensive lifestyles and larger populations, remain largely unchallenged.” The authors of that chapter offer one takeaway in clear terms, stating that “innovation and even fast technological change will not be enough to achieve Paris Agreement mitigation objectives. Other changes are necessary across the production and consumption system and the society in general, including behavioural changes.” We need more nuanced discussions of technological potential and greater focus on changes to our culture and lifestyles as a means of reducing emissions.

Of course, even with an understanding of the various approaches we must take to preserve a livable climate, there is no guarantee that they’ll be implemented. A major reason is the role of powerful interests that block efforts towards change. The IPCC’s exploration of social power is the topic we turn to next.


Teaser photo credit courtesy of Unsplash.

Aaron Karp

Aaron Karp

Aaron Karp is an activist writing a book about why our ecological crises demand economic and cultural transformation, not just an energy transition, and how the climate movement can lay the groundwork for these changes. He writes at and tweets @LimitsLiberate

Tags: clean energy transition, climate change mitigation strategies, IPCC reports