As the world shifts toward renewable energy sources, some experts warn that a lack of planning for the retirement of fossil fuels could lead to a disorderly and dangerous collapse of existing systems that could prolong the transition to green energy.As the world shifts toward renewable energy sources, some experts warn that a lack of planning for the retirement of fossil fuels could lead to a disorderly and dangerous collapse of existing systems that could prolong the transition to green energy.

In a study published in the journal Science, University of Notre Dame researchers Emily Grubert and Joshua Lappen argue that fossil fuel systems might be far more fragile than current energy models assume.In a study published in the journal Science, University of Notre Dame researchers Emily Grubert and Joshua Lappen argue that fossil fuel systems might be far more fragile than current energy models assume.

"Systems designed to be large and growing behave differently when they shrink," said Grubert, associate professor of sustainable energy policy at Notre Dame's Keough School of Global Affairs and a faculty affiliate of the Keough School's Pulte Institute for Global Development. "Ignoring this shift puts everything at risk, from the success of green energy to the basic safety and reliability of our power."

The researchers introduced the concept of "minimum viable scale," a threshold of production below which a fossil fuel system can no longer function safely or economically. They provided examples of vulnerabilities in three major sectors:

• Petroleum refineries: Most refineries are incapable of operating normally at low capacity and likely have "turndown limits," or a minimum operational capacity, of roughly 65% to 70%. If gasoline demand drops sharply due to electric vehicle adoption, for example, a refinery might become incapable of providing other products such as jet fuel or asphalt.
• Natural gas pipelines: As customers switch to electric heating and cooling, those remaining on the gas grid will have to shoulder the fixed costs of maintaining miles of pipelines. This can create a "death spiral" where rising costs drive customers away.
• Coal generation: The authors highlighted a "managerial constraint" where the fate of coal mines and power plants is inextricably linked. A single plant closure can make a local mine unprofitable. Conversely, a mine closure can leave a power plant without its specific, geographically dependent fuel source, leading to a cascade of failures.

The researchers report that the decline of fossil fuels is unlikely to follow the smooth, linear path often depicted in hypothetical decarbonization scenarios. Instead, they identify a series of physical, financial, and managerial "cliffs" that could trigger localized energy crises, price shocks, and safety threats long before fossil fuels are retired."Systems designed to be large and growing behave differently when they shrink," said Grubert, associate professor of sustainable energy policy at Notre Dame's Keough School of Global Affairs and a faculty affiliate of the Keough School's Pulte Institute for Global Development. "Ignoring this shift puts everything at risk, from the success of green energy to the basic safety and reliability of our power."

The researchers introduced the concept of "minimum viable scale," a threshold of production below which a fossil fuel system can no longer function safely or economically. They provided examples of vulnerabilities in three major sectors:

• Petroleum refineries: Most refineries are incapable of operating normally at low capacity and likely have "turndown limits," or a minimum operational capacity, of roughly 65% to 70%. If gasoline demand drops sharply due to electric vehicle adoption, for example, a refinery might become incapable of providing other products such as jet fuel or asphalt.
• Natural gas pipelines: As customers switch to electric heating and cooling, those remaining on the gas grid will have to shoulder the fixed costs of maintaining miles of pipelines. This can create a "death spiral" where rising costs drive customers away.
• Coal generation: The authors highlighted a "managerial constraint" where the fate of coal mines and power plants is inextricably linked. A single plant closure can make a local mine unprofitable. Conversely, a mine closure can leave a power plant without its specific, geographically dependent fuel source, leading to a cascade of failures.

The researchers report that the decline of fossil fuels is unlikely to follow the smooth, linear path often depicted in hypothetical decarbonization scenarios. Instead, they identify a series of physical, financial, and managerial "cliffs" that could trigger localized energy crises, price shocks, and safety threats long before fossil fuels are retired.

Policymakers have focused intensely on the build-out of green energy while largely ignoring the managed decline of the current systems that still provide 80% of global energy—a critical oversight, they said.

"None of these systems were designed with their own obsolescence in mind," said Lappen, a postdoctoral researcher at the Pulte Institute who studies how energy networks grow and shrink over time.

"None of the engineers, founding executives, economists, or accountants involved ever imagined a system that would gradually and safely hand off to another."

The danger, according to the authors, is that these systems are "networks of networks." If one piece fails—a pipeline, a specialized labor pool, or a regulatory body—the entire regional energy support system could dissolve.

"If you are leaving decisions about things staying open or closing to individual operators who are not coordinated in any way, this can be incredibly dangerous," Grubert said.

How to manage decline

To avoid disruption of services, the researchers argued that the current U.S. approach of bailouts and bankruptcies is inefficient. They recommended four key solutions for policymakers and energy modelers:

• High-resolution modeling: Energy modelers should develop tools that provide high-resolution representation of fossil fuel assets to identify when specific facilities reach their minimum viable scale.
• Coordination across ownership boundaries: Policymakers must establish management structures that coordinate decisions across ownership boundaries to prevent a single failure from triggering a cascade of collapses.
• Public management for public need: As systems become unprofitable, they may require significant new investments to remain safe and reliable in the short term, while still committing to closure. Such decisions should be managed by government entities.
• Guaranteed liabilities: Governments should create mechanisms to guarantee the payment of long-term liabilities—"bills" due at the end of a project such as safely tearing down power plants, cleaning up polluted soil, or paying out pensions to workers—to ensure that declining systems are not simply abandoned by private operators.

Without such intervention, the authors warn, the "mid-transition" period to zero carbon energy could be defined by instability. If the decline is unmanaged, the resulting price spikes and reliability issues could undermine public trust in the energy transition itself, potentially stalling progress toward meeting important climate goals.

"We will be more creative and more successful if we think about the process outside the moment of crisis," Grubert said. "Focusing more attention on the behavior of fossil systems under decline can help put timely solutions into place."

More information: Joshua Lappen, Fossil energy minimum viable scale, Science (2026). DOI: 10.1126/science.aea0972. www.science.org/doi/10.1126/science.aea0972Policymakers have focused intensely on the build-out of green energy while largely ignoring the managed decline of the current systems that still provide 80% of global energy—a critical oversight, they said.

"None of these systems were designed with their own obsolescence in mind," said Lappen, a postdoctoral researcher at the Pulte Institute who studies how energy networks grow and shrink over time.

"None of the engineers, founding executives, economists, or accountants involved ever imagined a system that would gradually and safely hand off to another."

The danger, according to the authors, is that these systems are "networks of networks." If one piece fails—a pipeline, a specialized labor pool, or a regulatory body—the entire regional energy support system could dissolve.

"If you are leaving decisions about things staying open or closing to individual operators who are not coordinated in any way, this can be incredibly dangerous," Grubert said.

How to manage decline

To avoid disruption of services, the researchers argued that the current U.S. approach of bailouts and bankruptcies is inefficient. They recommended four key solutions for policymakers and energy modelers:

• High-resolution modeling: Energy modelers should develop tools that provide high-resolution representation of fossil fuel assets to identify when specific facilities reach their minimum viable scale.
• Coordination across ownership boundaries: Policymakers must establish management structures that coordinate decisions across ownership boundaries to prevent a single failure from triggering a cascade of collapses.
• Public management for public need: As systems become unprofitable, they may require significant new investments to remain safe and reliable in the short term, while still committing to closure. Such decisions should be managed by government entities.
• Guaranteed liabilities: Governments should create mechanisms to guarantee the payment of long-term liabilities—"bills" due at the end of a project such as safely tearing down power plants, cleaning up polluted soil, or paying out pensions to workers—to ensure that declining systems are not simply abandoned by private operators.

Without such intervention, the authors warn, the "mid-transition" period to zero carbon energy could be defined by instability. If the decline is unmanaged, the resulting price spikes and reliability issues could undermine public trust in the energy transition itself, potentially stalling progress toward meeting important climate goals.

"We will be more creative and more successful if we think about the process outside the moment of crisis," Grubert said. "Focusing more attention on the behavior of fossil systems under decline can help put timely solutions into place."

More information: Joshua Lappen, Fossil energy minimum viable scale, Science (2026). DOI: 10.1126/science.aea0972. www.science.org/doi/10.1126/science.aea0972