What is thermal runaway?
As more renewable energy projects are developed and come online, there is an increasing need for large-scale energy storage development. A battery energy storage system (BESS) is able to store excess electricity generated by certain renewable energy sources (such as solar and wind) and when needed, quickly inject that electricity back into the electrical grid to meet ramping, peak demand needs, and other reliability requirements. Along with its benefits, energy storage with lithium-ion batteries introduces the risk of thermal runaway, a chemical reaction that can occur when the temperature inside the battery strays outside its optimal operating range. Thermal runaway can cause battery malfunction or, at its worst, large fires that pose an air quality risk to surrounding areas. As a result, energy storage developers are required to prepare a Thermal Runaway Study to address concerns raised during the permitting process. The assessment can help determine whether a project as designed poses a considerable health risk to nearby land uses. Assessment early in the design of the project can help avoid potential impacts and reassure interested parties that the risk has been analyzed and fully mitigated.
What does a thermal runaway study include?
A thermal runaway risk assessment, hazard analysis, or hazard assessment evaluates a project’s potential to cause adverse health effects on nearby sensitive receptors (e.g., residences, schools, playgrounds, childcare centers, healthcare facilities, retirement homes, etc.) in the unlikely scenario of a thermal runaway event. The assessment includes:
- Quantification of potential toxic air contaminants that could be released during a thermal runaway event;
- Identification of reference exposure levels for those toxic air contaminants; and
- Location of impacts in relation to the closest receptors.
The evaluation also determines the distances that flammable vapor clouds could travel under different meteorological conditions following a potential battery cell malfunction scenario.
Dudek Senior Air Resources Specialist Adam Poll said, “We have seen lead agencies regularly request preparation of these assessments over the past few years as BESS projects have become more common.” For a battery storage project in Virginia, Dudek prepared a thermal runaway study to inform the public, local decision-makers, as well as the local fire authority. After reviewing the assessment Dudek prepared, the local fire authorities redacted their prior opposition to the project and the local governing body approved the project to be built.
Leveraging our experience preparing thermal runaway hazard analyses across California, Virginia, and the nation, we save developers time and money by ensuring the potential risk of thermal runaway is addressed early in the development process. To the extent possible, our experts rely on pre-formatted templates to streamline preparation. In cases where a developer does not have a battery supplier identified at the time the assessment is prepared, we rely on the proposed battery chemistry and other Dudek-prepared thermal runaway studies of that same chemistry to serve as a surrogate for the project. This ensures that the assessment is prepared as efficiently as possible.
How does a thermal runaway hazard analysis mitigate risk?
Preparation of a thermal runaway study concurrent with other environmental studies during the entitlement process helps avoid processing delays if the assessment is instead requested by the lead agency later or must be prepared in response to public concern. Our technical experts prepare these assessments in a defensible manner, avoiding costly back and forth between reviewing and commenting agencies. When performed during the entitlement process, a thermal runaway study can inform the developer of any design changes needed to reduce potential impacts associated with the project. This reduces the risk of the project being challenged during public comment, rejected by the lead agency, or litigated by concerned parties.
“In the short term these analyses are a very important tool for both developers and lead agencies for both project design and public disclosure,” Poll said. “In the long term, as battery chemistries and regulations evolve, the need for these assessments may be reduced, but that will entirely depend on the inherent safety mechanisms built into the energy storage technology.”
How can Dudek help?
Dudek has a comprehensive understanding of the energy development process based on 20+ years of building a focused energy team of permitting project managers, environmental compliance managers, and environmental specialists dedicated to ensuring energy storage projects meet project milestones. Dudek understands the unique challenges of permitting battery storage facilities in an array of settings, from rural farmland to densely populated cities. Although battery technology has been available for decades, the use of battery storage for grid-scale renewable energy resources is a relatively new concept to most regulatory agencies. Our permitting experts help developers understand the appropriate permit applications, studies, and design considerations to efficiently obtain entitlements based on the local agency requirements.