Preparing the Power System for a Changing Climate

EPRI Launches the Climate READi Initiative

By Chris Warren

Chronicling extreme weather these days can be an exercise in the use of superlatives. The past seven years, for instance, have been the hottest in recorded history.

The extreme weather in 2021 included an extraordinary cold spell in Texas, known as Winter Storm Uri, which led to power outages that impacted 10 million people and contributed to over 200 deaths. Although not presently attributed to climate change, events like Winter Storm Uri demonstrate the need to consider and plan for the full range of climate conditions that could affect the electricity system in different locations.

Another example—more closely linked to climate change—was the heat dome that descended on the Pacific Northwest and broke records for all-time high temperatures in Seattle and Portland. The so-called whiplash effect of some weather extremes was also evident in 2021. In one instance, intense drought and wildfires spread across the western United States, even after California was hit by heavy rains and flooding in early 2021.

Overall, 2021 was a year of record-setting extreme weather events across the United States. According to the National Oceanic and Atmospheric Administration (NOAA), there were 20 individual weather and climate disasters whose overall losses exceeded $1 billion. In total, extreme weather across the country caused nearly 700 deaths and close to $150 billion in damages.

What were once accurately referred to as 1-in-50 or 1-in-100-year floods, droughts, or heatwaves may now occur more regularly or be more intense. Although many factors contribute to changing weather extremes, including natural climate variability, it is clear that the electric power system is increasingly exposed to multiple extreme weather and climate-related hazards that can produce severe consequences for customers if not adequately planned for.

This need is only exacerbated by society’s growing dependence on electricity as a final energy source, driven in large part by decarbonization efforts. As a result, the industry needs to focus on proactively preparing the power system for the climate conditions of today and the future.

Acute and Chronic Climate-related Impacts on the Power System

Increasingly frequent and severe extreme weather has been accompanied by more extensive power outages, underlining the need to examine power system preparedness in relation to current and future climate conditions. A recent Associated Press analysis of utility data submitted to the U.S. Department of Energy (DOE) found that the number of severe weather-related outages more than doubled from about 50 each year in the early 2000s to over 100 in each of the past five years. On average, U.S. customers experienced about eight hours of power outages in 2020.

The physical impacts of climate on the power system, and the potential changes associated with climate change, aren’t limited to intense heatwaves, wildfires, and other extreme events—also known as acute climate impacts. More incremental, chronic climate impacts also pose challenges. For example, over the past few decades, unusually hot summer days have become more common across the contiguous 48 states, according to data from the U.S. Environmental Protection Agency (EPA).

Both acute and chronic climate impacts can have significant implications for the operation of a resilient and reliable electric power system. In fact, the challenges posed by a changing climate are increasingly apparent in all aspects of the power system, from generation to delivery to customer utilization, as well as power company operations, including planning, operations, and response to outages.

A Collaborative Approach to Power System Resilience and Adaptation

In response to the need to prepare the power system against the effects of climate change, EPRI launched the Climate Resilience and Adaptation Initiative (Climate READiTM) in April. The initiative is built on the understanding that the resilience of the electric power system requires unprecedented collaboration among utilities, regulators, policymakers, climate scientists, communities, and other stakeholders. It’s also driven by the belief that adaptation and resilience investments must be responsive to unique local conditions and guided by technically rigorous and scientifically-informed insights that consider everything from worker health and safety to nature-based solutions.

“The motivation for this work is that we have observed changes in climate and understand that more change may be coming in the future,” said Laura Fischer, a technical leader for climate resilience analysis at EPRI and technical lead for the Climate READi Workstream, Physical Climate Data, and Guidance. “The power system is affected by climate change and climate generally because it’s a physical system exposed to weather-related hazards. The way the system is planned, designed, and operated has to be influenced by our understanding of current and changing weather and climate conditions.”

Climate READi will leverage decades of research by EPRI, U.S. National Research Laboratories, the DOE, academic institutions, and others to create a comprehensive, industry-accepted framework to guide electricity system adaptation and resilience decisions and investments. Working collaboratively is a way to avoid duplicating research efforts and enhance transparency and confidence in the common framework.

The initiative currently has 18 members, including AES, Alliant Energy Corporation, Ameren Corporation, American Electric Power, Consolidated Edison Co. of New York, Exelon Corporation, National Grid PLC, New York Power Authority, Pacific Gas & Electric, Portland General Electric, PPL Corporation, Puget Sound Energy, Seattle City Light, Southern California Edison, Southern Company, Southwest Power Pool, Vistra, and WEC Energy Group.

The initiative will ultimately result in the creation of a series of Climate READi Power Guidebooks and other decision-support tools that will provide detailed guidance about how to implement different aspects of the framework.

For example, the Climate READi framework will:

• Provide guidance on the specific climate and secondary physical data, datasets, variables, specifications, and interpretation needed to facilitate the assessment of a full range of power system-related applications. This includes characterizing how to treat the inherent uncertainty of climate and ecosystem modeling in power system applications.
• Deliver a consistent approach that power system stakeholders can use to apply climate-related information, including data about extreme weather and locationally specific climate data trends. This information can be used to analyze the potential vulnerability to chronic and acute climate impacts of individual assets and the system as a whole.
• Develop a common risk-based approach to prioritizing electricity system resilience and adaptation investments and decisions. It’s impractical to expect that all new and existing electricity system assets can be made invulnerable to all climate impacts. The framework aims to build a cost-benefit analysis to evaluate and identify the adaptation investments that should be made to deliver an acceptable level of climate resiliency while also achieving other electricity system objectives, such as decarbonization, affordability, and equity.
• Provide stakeholders with confidence that the methods and approaches used in the framework are science-informed, technically rigorous, well-vetted, and consistently applied across the industry while still being flexible enough to account for regional differences in future climate trends and system configurations. At the same time, the framework seeks to understand the inherent uncertainty and limitations of methods and approaches so that the users of the guidebooks can be well informed when considering and prioritizing investments.

While Climate READi is focused on bolstering the resilience of the electricity system, the imperative of achieving that goal has much broader societal implications, as electricity is projected to meet greater energy demand in the future. Many states, for instance, have identified electrification as a key strategy for achieving emissions reduction goals.

According to the Clean Energy States Alliance, states from New York and Connecticut to New Mexico and California have set goals to achieve 100 percent carbon-free electricity by 2050 or sooner.

At the federal level, the Biden administration set a goal of decarbonizing the electric power sector by 2035 as part of a larger effort to reduce greenhouse gas emissions by 50 to 52% across the entire economy by 2030 and achieve net-zero emissions by 2050. As transportation, heating and cooling, industry and other sectors increasingly rely on electricity, society depends on the entire electricity system being prepared to withstand the impacts of a changing climate.

Three Climate READi Work Streams

To develop a common and consistent framework to inform power system planning, operations, and investments, Climate READi includes three work streams. They are:

Physical climate data and guidance. Utilities have long made data-driven decisions to plan and operate their assets to maximize efficiency for their local conditions. Design choices for substations, power plants, and transmission and distribution lines have typically been based on a historical understanding of the local climate, including the occurrence of weather extremes. But as the understanding of trends in future climate variables and weather events improves, there is an opportunity for decisions to reflect that improvement. “We are focused on understanding the climate data requirements to make informed decisions about the physical risk to electricity systems or to make better investment decisions in the future,” said Fischer.

Data on historical and current climate comes from both information collected at surface stations worldwide and reanalysis that combines observation data, including satellite measurements, with weather forecasting models to produce a more coherent picture of the past.

Forward-looking weather and climate data can be produced from near-term weather forecasting models or statistical extrapolations, as well as global climate models that simulate future decades to make projections about longer-term changes in variables such as temperature, precipitation, and wind speeds. Outputs from climate models can serve as inputs to secondary models to project future trends in other climate-related events like wildfire or drought.

Determining which data should be used in power system applications – and identifying data gaps—is not straightforward. This work stream seeks to identify relevant data that can be used to understand individual asset and power system vulnerabilities; it also will provide guidance about using the data in specific analysis contexts.

“It gets tricky because interpreting and consuming this vast world of climate data requires its own set of literacy skills,” Fischer said. “One of the goals of this work is to provide guidance about how to apply the right climate data to specific circumstances. In the absence of uniform guidance that can be tailored to local conditions, companies are left to find their own way. That ends up being a heterogeneous approach where everyone has their own piecemeal solution.”

Energy system and asset vulnerability assessment. The power system is made up of a vast collection of assets, from power plants and transmission lines to substations, feeders, and distribution lines. This work stream will apply the guidance on selecting and applying climate data produced in the first work stream to assets across the power system. The aim is to determine whether exposure to changes in chronic and acute climate hazards poses a substantial concern to their reliable operation.

“We are trying to build the tools and processes to assess the risks to assets based on their location and the climate data and modeling,” said Brandon Delis, an EPRI director leading work stream two, along with colleague Jeffrey Thomas. This work stream will produce a probabilistic risk analysis methodology for analyzing asset vulnerability. This comprehensive approach for gauging risk includes an evaluation of what could go wrong, how likely it is that a specific problem could arise, and what the consequences would be.

Climate change can negatively impact power system assets in many potential ways. For example, a report by the DOE’s Oak Ridge National Laboratory found that high ambient air temperatures can reduce the efficiency of thermal power plants and lower their overall generation capacity. Hydropower plants have reduced generation in the drought conditions that have settled over much of the western United States—in fact, every one-foot decline in Lake Mead results in a five- to six-megawatt loss of capacity at Hoover Dam.

The location and design criteria of individual plant assets also play an important role in their resilience to climate change. “In the power industry, climate models generally project a decrease in extreme cold events. But they don’t project that they will disappear altogether,” Delis said. “This is challenging for the power sector, particularly in places that historically don’t experience much extreme cold. Even if these events happen less often, you still need to be prepared for them because their consequences can be catastrophic.”

Delis says the first task of the work stream will be to collaboratively figure out what is already known about asset vulnerability and what still needs to be researched to close knowledge gaps.

Resilience/adaptation planning and prioritization. Improving the power system’s resilience to weather extremes and more chronic impacts of climate change requires investment. But the reality is that budgets for those adaptation and mitigation investments are limited and must be targeted in ways that deliver the biggest and most equitable benefits to both the power system and society.

The aim of work stream three is to build on the climate data and asset vulnerability efforts to develop a framework to prioritize investments. “That framework will look at impacts across generation, transmission, distribution, and the customer to develop consistent ways to compare risk mitigation options and consider investments,” said Anish Gaikwad, a program manager at EPRI who is heading up work stream three. “In addition to the power system, we will also look at societal impacts since you will have extreme climate events that will impact the health and safety of people, and we want to make sure the risk mitigation options are equitable.”

Put another way, the framework to be developed will provide a cost-benefit analysis to guide investments to address the most concerning risks to both the power system and society. Many factors go into that prioritization. For example, imagine that climate modeling projects that the average number of extreme heat days in a certain location will increase. That increase could lead to a reduction in both generator output and transmission line capacity, reducing the amount of electricity that could be delivered to a community. At the same time, demand for air conditioning could spike.

Working through all those complex factors with a consistent framework is essential. It will help inform the work of the long-term system, resource, and transmission and distribution planners as well as utility decision makers and regulators.

The framework developed will also be useful in preparing for non-climate impacts. “The aim is to be able to also consider non-climate extreme events, like earthquakes, because at the end of the day, we want to be able to assess the range of impacts on the power system,” Gaikwad said. “It also will consider other utility objectives around long-term reliability and decarbonization pathways. Climate change can’t just be thought of in isolation from other utility objectives.”

As Climate READi launched in April, many utilities have already signed up to participate, indicating the industry-wide recognition that action should be fast and collaborative. “It’s incredible to see the momentum with which Climate READi is already moving. Proactively strengthening grid resilience against potential climate and weather impacts, now and in the future, will require unprecedented collaboration among the power sector and its stakeholders,” said Arshad Mansoor, president and CEO of EPRI. “For years, utilities have done a great job of responding to extreme events—raising substations, installing concrete poles—but this framework will provide a consistent way to evaluate and prioritize proactive investments that can mitigate the risks of extreme weather and chronic climate change for the power system.”

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