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The World Has Changed. The West Has Changed. Our Approaches Must Change.

image credit: WECC
Amanda Sargent's picture
Senior Resource Adequacy Analyst Western Electricity Coordinating Council (WECC)

Experienced with electric and natural gas utilities, specializing on integrated resource planning, cost-effectiveness testing and energy efficiency program management and design. Am passionate...

  • Member since 2018
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  • Jan 25, 2022

This item is part of the Power Industry 2022 Trends & Predictions - January 2022 SPECIAL ISSUE, click here for more

Throughout the West’s diverse energy resource portfolio, in recent years there has been a shift away from large baseload resources (e.g., coal, nuclear) toward more renewable and largely variable resources. This transition requires new methods of resource planning. In response, the Western Electricity Coordinating Council (WECC) developed a probabilistic tool for performing resource adequacy assessments and an interconnection-wide assessment of resource adequacy over the next 10 years, called the Western Assessment of Resource Adequacy, or Western Assessment.

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The 2021 Western Assessment concludes resource adequacy risks to reliability are likely to increase over the next 10 years. WECC recommends entities take immediate action to mitigate near-term risks and prevent long-term risks. Approaches to evaluating and planning for resource adequacy must adapt to changes affecting the system and evolve to ensure future reliability. The world has changed. The West has changed. These changes appear not only destined to continue, but to accelerate. If reliability and resilience are to be maintained, our planning, analyses, and ideas about resource adequacy must also change.

Based on current projections, by 2025 each region and the interconnection will be unable to meet a 99.98% one-day-in-ten-year (ODITY) reliability threshold because they will be unable to eliminate the hours at risk for loss of load even if all planned resource additions are built and power is imported.

The assessment relies on data collected from BAs describing their demand and resource projections. It evaluates resource adequacy across the entire interconnection and each of the five subregions.

The assessment uses two approaches to evaluate resource adequacy. The first is an energy-based probabilistic approach that evaluates potential demand and resource availability for each hour over the 10-year study period (2022–2031) to identify instances in which there is a risk of load loss. The second approach combines information from the probabilistic analysis with a deterministic model to examine how the system reacts to specific system conditions. The deterministic approach highlights risks associated with a few extreme scenarios.

Several conditions create the backdrop for this assessment, including a shift in the diversity of the interconnection, changes in demand and resource variability, the rapid pace of change, and the fact that resource adequacy must be analyzed and addressed across multiple time frames.

WECC’s analysis of resource adequacy over the next 10 years reveals the following takeaways:

  • Both demand and resource availability variability are increasing and the challenges they present appear worse now than they did in the 2020 Western Assessment of Resource Adequacy.
  • Under current planning reserve margins (PRM), all regions in the West show many hours at risk of load loss over the next 10 years.
  • To mitigate resource adequacy risks over the near-term (1 to 4 years) and long-term (5 to 10 years), PRMs need to be increased - in some cases significantly - or other actions taken to reduce the probability that demand exceeds resource availability.
  • Resource adequacy risks could get worse before they get better if action is not taken immediately to mitigate near-term risks and prevent long-term risks.

Findings show historical approaches to resource planning, if unchanged, will result in a significant degradation of resource adequacy. The typical deterministic approach to resource planning finds the peak demand hour, applies a flat, fixed planning reserve margin, and compares this information to the expected generation capacity. This approach assumes when the highest demand hour is resource adequate, all other periods are as well. Previously, this approach has been successful because system variability was low, so entities could rely on consistent resource availability. However, system variability is growing, reducing the consistency and predictability of resource availability.

Looking ahead, as resource availability variability increases with the growing portions of renewables, the certainty of previous levels of imports decreases, leading to reliance on imports becoming more precarious. Reduced availability of excess generation, coupled with increased demand for imports, can result in several entities relying on the same resource for imports to be available.

WECC encourages planners adopt energy resource adequacy planning regimens, rather than capacity based, with a focus on times of highest constraint, rather than peak demand. WECC also recommends planning entities and their regulatory authorities consider moving away from a fixed planning reserve margin to a probabilistically determined margin. As variability grows, a dynamic planning reserve margin will better ensure resource adequacy for all hours. Further, WECC recommends planning entities regularly recalibrate PRMs when there are significant changes to resources or demand that may increase the variability on the system.

The 2021 Western Assessment includes additional analysis as well as in-depth findings for each of the five subregions. WECC is looking forward to working with stakeholders on resource adequacy through future Resource Adequacy stakeholder engagement events, expanding to meet the needs of the West’s ever-evolving bulk power system.

Bob Meinetz's picture
Bob Meinetz on Jan 26, 2022

"Looking ahead, as resource availability variability increases with the growing portions of renewables, the certainty of previous levels of imports decreases, leading to reliance on imports becoming more precarious."

Amanda, you're right - that's exactly what's happening. But it seems you're making a simple problem far more complicated than necessary. Get rid of renewables, and the problem goes away - they're more trouble than they're worth.

More, and more, I'm realizing the WECC will have to collapse before decisionmakers will understand why adopting intermittent, renewable energy is a transition to failure, a problem with no answer. And for the sake of slowing climate change I hope it happens soon.

Amanda Sargent's picture
Amanda Sargent on Jan 28, 2022

Thank you for the comment, Bob!

We agree there’s no desire for over-complication. Whether solutions to resource adequacy come in the form of renewables, microgrids, batteries, nuclear, coal or gas - WECC is fuel agnostic. WECC’s mission is to effectively and efficiently mitigate risks to the reliability and security of the Western Interconnection’s Bulk Power System (BPS).


WECC annually gathers information on the current state of the BPS as well as the balancing areas’ utility planners’ assumptions for the next ten years, usually based on their Integrated Resource Plans, their proposed acquisition and retirement strategies, and reflecting a diverse range of local, state and federal energy policies. WECC’s unique, international to local perspectives allow assessment of the potential reliability performance of the whole Western Interconnection, from the provinces of British Columbia and Alberta, down through 14 western states and the northern portion of Baja Mexico, rolling up results for public digestion into each of the five subregions presented above.


One of the values WECC brings to BPS reliability assessment stems from in its policy, technology and geographic neutrality.

Bob Meinetz's picture
Bob Meinetz on Jan 30, 2022

Amanda, WECC's dedication to system reliability is admirable and sorely needed, given California's current state of affairs.

My concern is that Berkshire-Hathaway subsidiary Pacificorp is building a vast transmission network, the Energy Gateway South, to bring power from other western states (primarily Wyoming) to California. Meanwhile, our state's PUC plans to import 4 gigawatts of electricity to replace clean electricity from Diablo Canyon Power Plant, a carbon-free nuclear plant, after its planned closure in 2024-25.

Now, you say WECC is "fuel agnostic", but that's a problem. If electricity is being imported from PacifiCorp's coal plants in Wyoming, it will increase California's carbon footprint by up to 9 million metric tonnes annually (that California CO2 is being emitted in Wyoming is irrelevant - CO2 has the same impact on climate no matter where it's emitted).

Furthermore, it would be illegal. CA Senate Bill 1090 requires Diablo Canyon's carbon-free electricity be replaced with electricity that will not result in an increase in carbon emissions. To bypass that requirement, CPUC is planning to import electricity under the generic category of "unspecified imports" - a blatant violation of California law. To prevent that from happening, environmental forces in California are already mobilizing to tie PacifiCorp's access to our state in litigation, for as long as necessary.

I can't believe it's impossible for WECC to specify the sources of various contributors to its interstate grid. After all, power purchase agreements will exist for those purchases, and as the only entity capable of tracking sources of electricity in real time it would behoove WECC to accept that responsibility - to ensure every state's imports are consistent with local laws, and to prevent costly legal delays from preventing access to California's lucrative electricity market. Would it not?

Amanda Sargent's picture
Amanda Sargent on Feb 1, 2022

Lots of good ideas. Note, some of what you suggest falls outside WECC’s delegated purview, such as resource selection. The purpose of the probability forecasting is to take what plans and decisions are made by the utilities and system operators, within their states’ or provinces’ laws, and see if that portfolio’s mix will be reliable across a range of potential futures and the whole region.

That said, I can point to our publicly posted list of generation resource assumptions, which reflect current and planned portfolios over the next ten years, provided by the balancing areas across the Western Interconnection, for future reference:

The WARA’s assumptions can be found here:

The assumptions used for the NERC long term reliability assessment (LTRA) are posted here:

Bob Meinetz's picture
Bob Meinetz on Feb 2, 2022

Thank you, Amanda. Very helpful!

Gene Nelson's picture
Gene Nelson on Feb 3, 2022

Amanda: Thank you for your informative web links. Any chance they could incorporate the entire Western Interconnection? For example, no resources for PACE (PacifiCorp East) are tabulated in the spreadsheets you provided.

Amanda Sargent's picture
Amanda Sargent on Feb 4, 2022

Thanks for the comment Gene! Through the link, you'll find PACE is divided into PAID, PAUT and PAWY ;)

Vladimir Vinogradov's picture
Vladimir Vinogradov on Feb 2, 2022

Amanda, you are right. Renewables are unstable. The risks of new energy crises will rise and people will suffer, unfortunately. This can be avoided by using powerful, stable and relatively clean energy sources such as natural gas and nuclear power.

Amanda Sargent's picture
Amanda Sargent on Feb 4, 2022

Indeed, there will be a need for both baseload and flexible resources, be they natural gas, nuclear, hydro, pumped storage, batteries, hydrogen, demand response programs, energy efficiency and conservation incentives, Time of Use rates, or a future, yet to be seen offering. Thank you for the comment Vladimir!

Michael Keller's picture
Michael Keller on Feb 2, 2022

Easy to point out problems. The hard part is finding solutions.

While probability analyses can be helpful, a deeper dive into the root causes of the problems is required if practical solutions are to occur.  The results of such analyses may be unpopular with some, including the political class. However, public power organizations are in a good position to take a hard look at solutions, unlike private utilities that are more or less subject to the whims of those currently in office. As I recall, municipal power in California is not subject to bureaucrats in Sacramento.

Amanda Sargent's picture
Amanda Sargent on Feb 4, 2022

Interesting points - thank you, Michael!

Leo St. Hilaire's picture
Leo St. Hilaire on Feb 3, 2022

Thanks Amanda,

I definitely agree that there is a need for utilities to change how they plan their systems with the transition to renewables. It will require a different mindset going forward.



Amanda Sargent's picture
Amanda Sargent on Feb 4, 2022

Thank you, Leo!! The future is wide open and I look forward to seeing what other new methodologies will be invented to assess resource adequacy as the industry continues to evolve.

Amanda Sargent's picture
Thank Amanda for the Post!
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