Electric utilities across the United States are increasingly relying on wildfire spread prediction models to assess the risk associated with their assets. These simulations provide valuable consequence measures: acres burned, structures destroyed, population impacted. But there is an important limitation to keep in mind. Consequence measures are conditional on an ignition already having occurred. On their own, they do not represent the full expected risk of an asset.

To prioritize grid-hardening and mitigation efforts effectively, utilities need to understand not just what could happen if a wildfire starts, but how likely it is that one of their assets starts it.

Why Ignition Probability Varies Across Assets

When utilities focus solely on wildfire consequence, they are implicitly assuming that the probability of ignition is the same across all assets. In practice, it is not. The likelihood that a specific asset fails and causes an ignition depends on a range of factors: equipment age and deterioration, conductor type, span length, number of phases, and environmental conditions such as fuel type, vegetation density, slope, and local terrain. Two assets in the same fire-weather zone can carry very different ignition probabilities depending on their condition and surroundings.

Implications for Hardening Budgets

Understanding expected risk is important not just for day-to-day operations, but for short- and long-term grid-hardening decisions as well. When prioritization is based primarily on consequence, resources can flow toward assets that have already received significant hardening investment and now carry relatively low ignition probability. The law of diminishing returns applies: each additional dollar invested in an already-hardened asset yields progressively less risk reduction.

Asset hardening decisions are often structured through a risk spend efficiency (RSE) analysis, which weighs the expected reduction in risk against the cost of the mitigation. When RSE is calculated using conditional risk rather than expected risk, it tends to favor areas with the most extreme fire behavior potential regardless of how likely ignition actually is. Accounting for ignition probability helps ensure that hardening investments are directed where they will produce the most meaningful reduction in overall system risk.

Hardening budgets are finite. Whether the funding comes from utilities, ratepayers, or government programs, getting the prioritization right has real consequences for communities, for the environment, and for the utilities responsible for managing that risk.

This article is adapted from a piece originally published in Utility Dive.

Simply knowing that an asset could ignite a wildfire is not enough to make a sound hardening decision. Ignition probability tells you where a fire might start. It does not tell you what happens next, or how bad it could get. That distinction matters significantly when hardening budgets are finite and prioritization decisions have real consequences for communities and infrastructure.

As Buckley outlined in a Utility Dive article, ignition is not risk. Risk is the possibility of damage, loss, and harm occurring from an ignition. Two assets with similar ignition probabilities can produce very different outcomes depending on what lies in the potential fire’s path. Understanding that difference is what makes consequence modeling a planning tool, not just an analytical one.

Why Not All Ignitions Are Created Equal

All utility assets carry some probability of failure and ignition. That probability varies based on asset condition, age, design, conductor type, surrounding vegetation, slope, and local weather patterns. But even assets with identical ignition probabilities can pose very different levels of risk depending on where they sit and what a fire starting there would affect.

Consequence modeling addresses this by integrating fire spread prediction with forecasted weather to determine where a fire would travel from a specific asset ignition point and what it would impact along the way. The outputs, structures threatened, population exposed, acreage burned, give planners a concrete basis for comparing assets that ignition probability alone cannot provide.

Not all ignitions are created equal. Not all fires are created equal. Consequence modeling is what makes those differences visible and actionable.

Regulatory Context and Planning Implications

California’s Public Utility Commission regulations have brought consequence modeling and RSE analysis into formal wildfire mitigation planning requirements for utilities in that state. But the planning value of this approach extends well beyond California. Wildfire-related regulation is expanding in scope and complexity across other states, and the underlying logic, that utilities need to demonstrate not just what they did but why they prioritized it, applies regardless of the specific regulatory framework in place.

On the operational side, consequence data also informs Public Safety Power Shutoff (PSPS) decision-making. Knowing which assets pose the highest expected consequence under forecast conditions gives operators a more defensible basis for de-energization decisions than ignition probability alone.

A More Complete Basis for Investment Decisions

Consequence modeling does not replace engineering judgment or operational expertise. It gives planners and risk managers the information needed to make hardening decisions that are grounded in expected impact rather than visible hazard alone. For utilities building or refining their wildfire mitigation programs, integrating consequence modeling into the prioritization process is what moves asset hardening from reactive to systematic.

This article draws on analysis originally published in Utility Dive by David Buckley, former COO of Technosylva.

Hear from the CEO of PG&E, Patti Poppe, as she explains to Bloomberg News how technology is helping PG&E combat risk the of wildfire through advanced modeling, strengthened situational awareness, and improved decision making for asset hardening.

Watch & learn from a great discussion with Pedro Pizarro, CEO of Edison International, about how electric companies are finding success in hardening & adapting their grid to the growing threat of wildfire.