Assess Vulnerabilities

Identifying and scoring power sector vulnerabilities are vital components of the power sector resilience planning process. These processes evaluate the degree to which a power system or power system components, such as generators or transmission lines, may be adversely affected (e.g., damaged, destroyed, or disrupted operation) by a broad range of potential threats and their impacts. The purpose of this step is to learn about power system objectives, understand the key resources and systems necessary for staff to complete their work, and understand what would happen if those resources or systems were compromised. The next step of the power sector resilience planning process is a risk assessment, which is based on the likelihood of threats occurring and the severity of potential vulnerabilities. For more information on vulnerabilities to the power sector, refer to the presentation at the end of this section of the guidebook.


The identification of vulnerabilities is a key step in the power sector resilience planning process—following the identification of threats and their associated impacts. Table 3 describes the types of infrastructure, processes, and systems that may be evaluated in a power sector vulnerability assessment.

This document introduces the key steps in identifying power system vulnerabilities:

  1. Assessing existing conditions
  2. Identifying vulnerabilities
  3. Scoring vulnerabilities
  4. Resources

Vulnerabilities—weaknesses within infrastructure, processes, and systems, or the degree of susceptibility to various threats. Different measures can be taken to reduce vulnerability or improve adaptive capacity to threats to the power sector.

Threats—anything that can expose a vulnerability and damage, destroy, or disrupt the power system. Threats can be natural, technological, or human caused. Threats are not typically within the power system operator’s control. They can include wildfires, hurricanes, storm surges, and cyberattacks.

Table 3. Key Power System Infrastructure, Processes, and Systems Included in Vulnerability Assessments

Key Power System Infrastructure, Processes, and Systems

Asset security (perimeter fencing, guard stations)

Critical transportation routes for fuel and supplies

Fuel storage

Electric feeders



Switching capability

Reserve capacity

Generation stations

Transmission and distribution networks

Power sector workforce

Critical customers and demands

Others, depending on context

Training Materials: Introduction to Vulnerabilities
These slides provide additional background information and examples of power system vulnerabilities. 

1. Assess Existing Conditions

An understanding of the existing conditions of the power system in terms of location of assets, operational practices, political threats, and other factors, helps determine the ability of the power sector to respond and adapt under different operational conditions if a disruption were to occur1. This step is conducted to identify these factors and highlight the assets that need to be protected under various planning scenarios. An existing-conditions assessment begins with stakeholder interviews, data collection, and literature reviews of resources that include:

  • Integrated resource plans
  • Emergency plans
  • Maps and geographic data
  • Utility information
  • Historical data relating to disasters, extreme temperatures, and grid outages
  • Other available, relevant resources.

2. Identify Vulnerabilities

In the planning process, vulnerabilities are often identified together with threats and impacts. Understanding existing conditions, as well as potential threats and vulnerabilities, along the planning horizon for infrastructure, processes, and systems is important to enhancing resilience.

Many different types of vulnerabilities exist and need to be considered. Vulnerabilities may occur within the infrastructure (e.g., generation, transmission, distribution, customers, and others) or system processes (e.g., operations, workforce, planning, financial, and others) as illustrated in Table 4. Infrastructure vulnerabilities are often easy to address but tend to be expensive, while process vulnerabilities tend to be difficult to address but usually require relatively inexpensive fixes. Other location-specific vulnerabilities must also be identified to ensure a comprehensive list of potential vulnerabilities.

Table 4. Examples of Vulnerabilities

Examples of Vulnerabilities

Lack of backup systems and supplies or single points of failure in transportation route, electrical line, water supply, or fiber-optic cable.

Location prone to flooding, fire, etc.

Lack of cybersecurity defenses

Poorly resourced or under-trained workforce

Location-specific vulnerabilities identified by the resilience assessment team

Activity: Developing Vulnerability Statements and Assigning Vulnerability Severity Scores
Use this worksheet to identify vulnerabilities that a power sector may face from possible threats, form vulnerability statements, and assign a severity score to each.

Stakeholder interviews conducted by the resilience assessment team are a critical component of identifying vulnerabilities. Stakeholders have information that will inform—and may improve—the assessment and which may not be found in existing documents. This includes historical and anecdotal information about potential vulnerabilities. 

Stakeholders include staff that can identify key operations and assets as well as those who provide funding or services and manage systems and operations. Stakeholders may also include staff in different agencies, including grid operators, utilities, the ministries of energy or environment, independent power producers, and more. For information on forming resilience assessment teams and engaging stakeholders, refer to Step 1 of NREL’s Resilience Planning Roadmap (

3. Score Vulnerabilities

The next step in the process is to score the severity of the identified vulnerabilities. These scores will be combined with the threat likelihood scores (see the Threats section of this guidebook) to determine the total risk to the power system. Vulnerability severity scores are assigned using professional judgment—with information from the stakeholder interviews, data collection, and literature review of Steps 1 and 2, Assess Existing Vulnerability Conditions and Identify Vulnerabilities, respectively.

A review of documents and studies (e.g., development plans, community development master plans, natural hazard studies, contingency response plans, after-action reports following disasters or disruptions, grid outage reports on historical outages, emergency operation plans, fire station functionality reports, utility disaster response plans, and others) can aid in the scoring of vulnerabilities. Often, studies are conducted by outside experts (e.g., experts on earthquakes or cyclones), providing resources and insight that would be beyond the capabilities of most assessment teams.

The assessment team determines the severity score of each vulnerability (the magnitude or extent to which each vulnerability could negatively impact the power sector if it were to occur) through a scoring system of ranking the severity (magnitude of consequence) on the power system from low to high. Table 5 shows the qualitative and quantitative scores and associated threshold descriptions used to assign vulnerability scores. Threshold descriptions are provided as guides that can help in assigning scores. The score represents the degree to which an affected process, system, or population could be adversely affected as a result of a disruptive event (e.g., flooding, a large storm, or attack). In scoring each vulnerability, the following categories are considered:

  • Effect on delivery of power—the percentage of service disrupted, effects on power quality, etc.
  • Effect on capital and operating costs—additional costs for the reliable operation of the power system
  • Extent of health and safety impacts to the population—number of people and severity of potential impact on the health and safety of the population
  • Extent of environmental effects—metrics of the release of toxic materials, effects on biodiversity, changes to an area’s ecosystem, impacts on historical sites, and others.


Table 5. Qualitative and Quantitative Vulnerability Severity Scores and Threshold Descriptions

Vulnerability Severity Score

Threshold Descriptions





Highest magnitude of consequence. Entire power system would be impacted. Extreme financial impacts would exist.



Significant consequences to the organization. Majority of population served would be impacted. Staff tasks would be switched to emergency/critical operations. Significant financial impacts would exist.



Medium magnitude of consequence. The organization would be somewhat affected. Specific systems or functions would be substantially interrupted, but not all. Financial impacts would be expected to change budgeting plans or require reallocation of funds.



Slightly elevated consequence to the organization. The power sector may need to temporarily transition operations to backup systems to resolve failure. Limited financial impacts may become apparent.



Lowest magnitude (or severity) of consequence to the organization. The power sector would experience little to no affect or an in-place backup system would resolve the failure.




Developing Vulnerability Statements and Assigning Vulnerability Severity Scores
In this activity, you will identify vulnerabilities that your power sector may face from possible threats, form vulnerability statements, and assign a severity score to each.

Training Materials

Introduction to Vulnerabilities
These slides are intended to provide additional background information and examples of power system vulnerabilities. They can serve simply as a reference or can be used in local power sector resilience assessment workshops. 

Data and Tools

Publications and Case Studies

Planning a Resilient Power Sector

The provision of reliable, secure, and affordable electricity is essential to power economic growth and development. The power system is at risk from an array of natural, technological, and man-made threats that can cause everything from power interruption to chronic undersupply. It is critical for policymakers, planners, and system operators to safeguard their systems and plan for and invest in the improved resilience of the power sector in their countries. Through holistic resilience planning, actors can anticipate, prepare for, and adapt to the threats and stresses on the power system. Resilience planning identifies the threats, impacts, and vulnerabilities to the power system, and devises strategies to mitigate them.

Enhancing Power Sector Resilience: Emerging Practices to Manage Weather and Geological Risks

Over the past 20 years, natural disasters have become more frequent, and the costs of associated damages and losses are rising. In 2012 alone, the 357 natural disasters recorded worldwide resulted in 9,655 fatalities, 125 million victims, and US$157 billion in associated damages and losses. Far‐flung power infrastructure from upstream generation plants and transmission lines to downstream distribution networks and operational systems is particularly vulnerable to weather and geological events. Building a resilient power sector is likely to be particularly challenging in countries where the power supply system is weak or aging, which is the case in many developing countries.

Climate Change and the Electricity Sector: Guide for Climate Change Resilience Planning

This Guide provides a broad framework for assessing the vulnerability of electric utility assets and operations to climate change and extreme weather and developing appropriate resilience solutions. Vulnerability assessments help utilities to determine where and under what conditions their systems may be vulnerable to rising temperatures and sea levels, changing precipitation patterns, or more frequent and severe episodes of extreme weather. Resilience plans, which are informed by the findings of the vulnerability assessments, identify solutions and prioritize climate resilience actions and investments. By completing the key steps in this Guide (Figure ES.1), utilities will develop planning-level documents that identify specific actions for managing or mitigating climate change risks.

Vulnerability Assessment Methodologies: A Review of the Literature

This literature review provides an overview of the tools and methods used to measure vulnerability, as pertains to development interventions focused on economic strengthening, at the population level as well as the household and individual level.

Climate Change Vulnerability Mapping for Southeast Asia

This paper provides information on the sub-national areas (regions/districts/provinces) most vulnerable to climate change impacts in Southeast Asia. This assessment was carried out by overlaying climate hazard maps, sensitivity maps, and adaptive capacity maps following the vulnerability assessment framework of the United Nations’ Inter-governmental Panel on Climate Change (IPCC). The study used data on the spatial distribution of various climate-related hazards in 530 sub-national areas of Indonesia, Thailand, Vietnam, Lao PDR, Cambodia, Malaysia, and the Philippines. Based on this mapping assessment, all the regions of the Philippines; the Mekong River Delta in Vietnam; almost all the regions of Cambodia; North and East Lao PDR; the Bangkok region of Thailand; and West Sumatra, South Sumatra, West Java, and East Java of Indonesia are among the most vulnerable regions in Southeast Asia.

Climate Vulnerability Assessment: An Annex to the USAID Climate-Resilient Development Framework

A climate vulnerability analysis can identify the what, where, when, and why of vulnerability, considering the social, economic, and environmental systems upon which people depend. In this way, climate vulnerability assessments (VAs) offer valuable information to help reduce risk.

A Review of Climate Change Vulnerability Assessments: Current Practices and Lessons Learned from DOE's Partnership for Energy Sector Climate Resilience

Changes in climate and extreme weather, including increasing temperatures, decreasing water availability, more intense storm events, and sea level rise have already damaged or disrupted electricity services. In the absence of concerted action to improve resilience, the ability of electric utilities to produce and transmit electricity, adjust to changes in population and the economy, and meet consumer energy demands are vulnerable. An assessment of potential impacts and vulnerabilities can help utilities to better prepare for and be resilient to changing climate and extreme weather.

Examples of various approaches are highlighted throughout the report in order to demonstrate the current practices and begin to identify best practices in vulnerability assessments. This report also identifies common data gaps and resource limitations in an effort to inform areas of future research and investment that can help energy companies prepare for future climate change impacts.

U.S. Energy Sector Vulnerabilities to Climate Change and Extreme Weather

This report examines current and potential future impacts of climate trends on the U.S. energy sector. It identifies activities underway to address these challenges and discusses potential opportunities to enhance energy technologies that are more climate-resilient, as well as information, stakeholder engagement, and policies and strategies to further enable their deployment.