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Expert Witness Guides
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Areas of Expertise :
Energy, Utility Engineering, Electrical Engineering, Power Distribution, Cybersecurity
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Good Utility Practice in energy litigation focuses on whether a utility acted reasonably under the standards, industry practices, information, and conditions that applied at the time. This article explains how GUP relates to reliability and cybersecurity requirements, how experts evaluate utility conduct and causation, and the methodological problems that can expose expert testimony to Rule 702, Daubert, and Kumho challenges.
In many energy disputes, the key question is not whether a utility could have made a better decision after the fact. It is whether the utility acted reasonably based on what it knew at the time.
That is where Good Utility Practice, often called GUP, becomes important.
GUP does not demand perfection. It asks whether the utility’s decision fit within accepted utility practices or reasonable judgment, based on the facts known at the time, reasonable cost, good business practices, safety, reliability, desired results, and expedition.
The exact meaning of GUP depends on the source that controls the dispute. That may be a tariff, contract, statute, regulation, commission order, or reliability standard. Utility plans and internal policies may also matter, but attorneys should not assume they automatically define the controlling legal or operational standard.
Because of that, a strong GUP analysis has to start with the right standard, move through the actual records, and explain whether the utility’s conduct was reasonable under the circumstances.
This guide explains what Good Utility Practice means in energy litigation, why it matters, and how expert methodology, reliability, and vetting failures can affect whether expert testimony holds up under challenge.
Good Utility Practice looks at whether a utility’s conduct was reasonable, expeditious, consistent with accepted industry practice, and supported by the information available when the decision was made.
A sound GUP analysis usually considers:
This matters because utility disputes can look very different after an outage, wildfire, cyber incident, or infrastructure failure has already happened. A decision that seems imperfect in hindsight may still have been reasonable when viewed through the facts, risks, and constraints that existed at the time.
For attorneys, that distinction is critical. GUP is usually not a search for the ideal decision. It is a practical inquiry into whether the utility acted within an accepted range of reasonable utility practice under similar conditions.
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In many energy disputes, the key question is not whether a utility could have made a better decision after the fact. It is whether the utility acted reasonably based on what it knew at the time.
That is where Good Utility Practice, often called GUP, becomes important.
GUP does not demand perfection. It asks whether the utility’s decision fit within accepted utility practices or reasonable judgment, based on the facts known at the time, reasonable cost, good business practices, safety, reliability, desired results, and expedition.
The exact meaning of GUP depends on the source that controls the dispute. That may be a tariff, contract, statute, regulation, commission order, or reliability standard. Utility plans and internal policies may also matter, but attorneys should not assume they automatically define the controlling legal or operational standard.
Because of that, a strong GUP analysis has to start with the right standard, move through the actual records, and explain whether the utility’s conduct was reasonable under the circumstances.
This guide explains what Good Utility Practice means in energy litigation, why it matters, and how expert methodology, reliability, and vetting failures can affect whether expert testimony holds up under challenge.
Good Utility Practice looks at whether a utility’s conduct was reasonable, expeditious, consistent with accepted industry practice, and supported by the information available when the decision was made.
A sound GUP analysis usually considers:
This matters because utility disputes can look very different after an outage, wildfire, cyber incident, or infrastructure failure has already happened. A decision that seems imperfect in hindsight may still have been reasonable when viewed through the facts, risks, and constraints that existed at the time.
For attorneys, that distinction is critical. GUP is usually not a search for the ideal decision. It is a practical inquiry into whether the utility acted within an accepted range of reasonable utility practice under similar conditions.
GUP often becomes central when a case turns on whether a utility missed a warning sign, delayed maintenance, failed to create or preserve required records, or chose one reasonable option over another.
Attorneys may see similar reasonableness issues in many litigation and regulatory settings, depending on the governing jurisdiction, contracts, tariffs, utility plans, commission orders, and claims at issue, such as:
The key issue is usually not whether someone can now identify a different option. In most utility disputes, that is easy to do after the event. The stronger question is whether the utility’s decision was reasonable under the governing standard and the conditions existing at the time.
That question can shape discovery, expert selection, deposition strategy, and motions practice. If the case turns on accepted utility practice, the expert needs to explain the standard that applied, the records that mattered, and the connection between the alleged failure and the claimed harm.
Good Utility Practice continues to evolve as the grid becomes more complex. Modern disputes may involve extreme weather risks, renewable energy growth, inverter-based resources, and cybersecurity threats.
NERC develops reliability standards for bulk power system reliability, and many mandatory standards turn on defined terms such as the Bulk Electric System, or BES. Those standards do not become mandatory and enforceable in the United States unless FERC approves them. Attorneys should also check the applicable implementation plan and effective date because FERC approval and enforceability may not occur on the same date. NERC enforces approved reliability standards subject to FERC oversight, and FERC may also enforce them independently.
In 2025, FERC approved reliability standards that affect how ride-through performance is evaluated. PRC-029-1 addresses inverter-based resources, including solar PV, Type 3 and Type 4 wind, battery energy storage systems, and fuel cell devices, and focuses on how those resources perform during voltage or frequency disturbances. PRC-024-4 separately addresses frequency and voltage protection settings for synchronous generators, Type 1 and Type 2 wind resources, and synchronous condensers.
For attorneys, the takeaway is practical. A GUP dispute involving ride-through performance may require an expert who understands not just the general concept, but which standard applied, when it applied, and how it was implemented for the specific type of resource at issue. PRC-029-1 also phases in over time, with different compliance dates depending on whether a resource is a BES IBR or falls under the applicable non-BES IBR requirements. That means a ride-through dispute can come down to which compliance date actually applied to the resource in question, not just which rule.
Cybersecurity can also become part of the GUP analysis, especially when the dispute involves BES Cyber Systems, assets subject to applicable CIP standards, recovery planning, remote access controls, or other cybersecurity controls tied to the governing requirements. Depending on the facts, the analysis may involve electronic access controls, remote access controls, recovery planning, backup records, data preservation records, and records showing how the utility handled applicable cybersecurity requirements.
A weak expert opinion may talk about cybersecurity in broad terms but miss the real issue. The opinion may sound plausible at first, but it can fall apart if the expert cannot tie the criticism to the utility’s actual systems, applicable requirements, available access-control or recovery records, and other case-specific evidence.
A persuasive GUP opinion connects the records, standards, and industry practices to the conclusion. It does not simply announce that the utility acted reasonably or unreasonably.
A defensible review usually includes:
The timing issue can be decisive. An expert should be careful not to treat a later-adopted wildfire mitigation requirement, cyber-control expectation, or reliability standard as though it governed earlier conduct. Later standards may still provide context, but the expert has to explain why they matter and how they fit the time period at issue.
The same careful analysis applies to internal policies. A company policy may be relevant, but it does not automatically define the legal or operational standard. The expert still needs to explain whether the policy was mandatory, whether it reflected accepted industry practice, and whether any departure caused the claimed loss.
In federal court, Rule 702 requires the party offering the expert to show the court, more likely than not, that the testimony meets the rule’s admissibility requirements. The opinion must help the factfinder, rest on sufficient facts or data, use reliable principles and methods, and reflect a reliable application of those principles and methods to the facts of the case.
Energy-sector experience matters, but credentials do not carry an opinion by themselves. Courts also look at whether the expert used a reliable method and applied it carefully to the facts.
Under Daubert and Kumho, courts may consider factors such as testing, peer review, known or potential error rate, standards governing the method or technique, and general acceptance when those factors are reasonable measures of reliability for the opinion at issue. In utility cases, the reliability inquiry often focuses on whether the expert identified the right standard, reviewed the right records, used a fair comparison, and avoided unsupported conclusions.
GUP opinions often run into trouble when an expert:
In a wildfire case, it may not be enough for an expert to point to a tree contact or vegetation issue and say the utility fell short. The opinion needs to explain what rules applied at the time, what inspections were required, what the utility knew, and how those facts connect to the alleged failure.
In a cybersecurity dispute, an expert may point to a breach and assume that the utility’s controls were inadequate. That may not be enough. A reliable analysis should address the applicable cyber requirements, relevant cybersecurity controls, available access-control or recovery records, and whether the alleged control failure actually contributed to the incident.
What is Good Utility Practice?
Good Utility Practice generally refers to accepted utility practices, methods, or acts used or approved by a significant portion of the electric utility industry during the relevant time period. It also considers whether the utility’s judgment could reasonably have been expected to achieve the desired result at reasonable cost, while accounting for good business practices, reliability, safety, and regional industry practice.
Is Good Utility Practice the same as best practice?
No. GUP is not limited to the single best option. It asks whether the conduct fell within an acceptable range of industry practice under the applicable standard and the facts known at the time.
Why does GUP matter in utility litigation?
It gives courts, regulators, and parties a framework for judging utility conduct without relying only on hindsight. That is especially important in disputes involving maintenance, reliability, safety, cybersecurity, emergency response, and system planning.
What makes a GUP expert reliable?
A reliable GUP expert ties opinions to governing standards, industry practice, contemporaneous facts, and a clear, case-specific methodology that is better positioned to withstand Rule 702, Daubert, and Kumho scrutiny.
Why do GUP expert opinions get excluded?
GUP opinions may be challenged, limited, or excluded when the expert applies the wrong standard, relies on hindsight, treats best practices as mandatory requirements, ignores key records, or fails to connect the alleged breach to the claimed harm.
GUP often becomes central when a case turns on whether a utility missed a warning sign, delayed maintenance, failed to create or preserve required records, or chose one reasonable option over another.
Attorneys may see similar reasonableness issues in many litigation and regulatory settings, depending on the governing jurisdiction, contracts, tariffs, utility plans, commission orders, and claims at issue, such as:
The key issue is usually not whether someone can now identify a different option. In most utility disputes, that is easy to do after the event. The stronger question is whether the utility’s decision was reasonable under the governing standard and the conditions existing at the time.
That question can shape discovery, expert selection, deposition strategy, and motions practice. If the case turns on accepted utility practice, the expert needs to explain the standard that applied, the records that mattered, and the connection between the alleged failure and the claimed harm.
Good Utility Practice continues to evolve as the grid becomes more complex. Modern disputes may involve extreme weather risks, renewable energy growth, inverter-based resources, and cybersecurity threats.
NERC develops reliability standards for bulk power system reliability, and many mandatory standards turn on defined terms such as the Bulk Electric System, or BES. Those standards do not become mandatory and enforceable in the United States unless FERC approves them. Attorneys should also check the applicable implementation plan and effective date because FERC approval and enforceability may not occur on the same date. NERC enforces approved reliability standards subject to FERC oversight, and FERC may also enforce them independently.
In 2025, FERC approved reliability standards that affect how ride-through performance is evaluated. PRC-029-1 addresses inverter-based resources, including solar PV, Type 3 and Type 4 wind, battery energy storage systems, and fuel cell devices, and focuses on how those resources perform during voltage or frequency disturbances. PRC-024-4 separately addresses frequency and voltage protection settings for synchronous generators, Type 1 and Type 2 wind resources, and synchronous condensers.
For attorneys, the takeaway is practical. A GUP dispute involving ride-through performance may require an expert who understands not just the general concept, but which standard applied, when it applied, and how it was implemented for the specific type of resource at issue. PRC-029-1 also phases in over time, with different compliance dates depending on whether a resource is a BES IBR or falls under the applicable non-BES IBR requirements. That means a ride-through dispute can come down to which compliance date actually applied to the resource in question, not just which rule.
Cybersecurity can also become part of the GUP analysis, especially when the dispute involves BES Cyber Systems, assets subject to applicable CIP standards, recovery planning, remote access controls, or other cybersecurity controls tied to the governing requirements. Depending on the facts, the analysis may involve electronic access controls, remote access controls, recovery planning, backup records, data preservation records, and records showing how the utility handled applicable cybersecurity requirements.
A weak expert opinion may talk about cybersecurity in broad terms but miss the real issue. The opinion may sound plausible at first, but it can fall apart if the expert cannot tie the criticism to the utility’s actual systems, applicable requirements, available access-control or recovery records, and other case-specific evidence.
A persuasive GUP opinion connects the records, standards, and industry practices to the conclusion. It does not simply announce that the utility acted reasonably or unreasonably.
A defensible review usually includes:
The timing issue can be decisive. An expert should be careful not to treat a later-adopted wildfire mitigation requirement, cyber-control expectation, or reliability standard as though it governed earlier conduct. Later standards may still provide context, but the expert has to explain why they matter and how they fit the time period at issue.
The same careful analysis applies to internal policies. A company policy may be relevant, but it does not automatically define the legal or operational standard. The expert still needs to explain whether the policy was mandatory, whether it reflected accepted industry practice, and whether any departure caused the claimed loss.
In federal court, Rule 702 requires the party offering the expert to show the court, more likely than not, that the testimony meets the rule’s admissibility requirements. The opinion must help the factfinder, rest on sufficient facts or data, use reliable principles and methods, and reflect a reliable application of those principles and methods to the facts of the case.
Energy-sector experience matters, but credentials do not carry an opinion by themselves. Courts also look at whether the expert used a reliable method and applied it carefully to the facts.
Under Daubert and Kumho, courts may consider factors such as testing, peer review, known or potential error rate, standards governing the method or technique, and general acceptance when those factors are reasonable measures of reliability for the opinion at issue. In utility cases, the reliability inquiry often focuses on whether the expert identified the right standard, reviewed the right records, used a fair comparison, and avoided unsupported conclusions.
GUP opinions often run into trouble when an expert:
In a wildfire case, it may not be enough for an expert to point to a tree contact or vegetation issue and say the utility fell short. The opinion needs to explain what rules applied at the time, what inspections were required, what the utility knew, and how those facts connect to the alleged failure.
In a cybersecurity dispute, an expert may point to a breach and assume that the utility’s controls were inadequate. That may not be enough. A reliable analysis should address the applicable cyber requirements, relevant cybersecurity controls, available access-control or recovery records, and whether the alleged control failure actually contributed to the incident.
What is Good Utility Practice?
Good Utility Practice generally refers to accepted utility practices, methods, or acts used or approved by a significant portion of the electric utility industry during the relevant time period. It also considers whether the utility’s judgment could reasonably have been expected to achieve the desired result at reasonable cost, while accounting for good business practices, reliability, safety, and regional industry practice.
Is Good Utility Practice the same as best practice?
No. GUP is not limited to the single best option. It asks whether the conduct fell within an acceptable range of industry practice under the applicable standard and the facts known at the time.
Why does GUP matter in utility litigation?
It gives courts, regulators, and parties a framework for judging utility conduct without relying only on hindsight. That is especially important in disputes involving maintenance, reliability, safety, cybersecurity, emergency response, and system planning.
What makes a GUP expert reliable?
A reliable GUP expert ties opinions to governing standards, industry practice, contemporaneous facts, and a clear, case-specific methodology that is better positioned to withstand Rule 702, Daubert, and Kumho scrutiny.
Why do GUP expert opinions get excluded?
GUP opinions may be challenged, limited, or excluded when the expert applies the wrong standard, relies on hindsight, treats best practices as mandatory requirements, ignores key records, or fails to connect the alleged breach to the claimed harm.
Digital Evidence
Electronic Authentication
Evidence Analysis
Computer Data
Data Analysis
Data Mining Algorithm
Machine Bias
Software Audit
Litigation Support
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