Reliability and Resiliency Report 2025 (2025 Resiliency and Reliability Report)

GROWTH

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Resiliency and Reliability Report

DRIVING RESILIENCY AND RELIABILITY

Reliable energy is the backbone of our nation's economy and infrastructure, and Ameren plays a critical role for customers in the Midwest. The steps we are taking now are designed to enable the communities we serve to benefit from significant economic development opportunities that require that reliable energy. In the years ahead, we are prepared to capitalize

on those opportunities for the benefit of our customers, communities and shareholders.

Our country faces growing challenges from the increasing frequency of extreme weather events and aging infrastructure, while also preparing for rapidly rising energy demand. Recent events across Missouri and Illinois - including the May 2025 tornado outbreak, prolonged extreme heat during June and July 2025 that placed sustained stress on electric systems, and severe winter cold events such as the February 2021 polar vortex - demonstrate how extreme weather events challenge

grid performance and reliability, reinforcing the critical need for resilient, grid-hardened infrastructure.

To address these challenges, Ameren has planned $31.8 billion in regulated infrastructure investments from 2026-2030

to modernize electric and gas infrastructure, enhance grid intelligence, and improve reliability and resilience, while advancing efforts to prepare for increasing demand.

Missouri's Smart Energy Plan and Ameren Illinois' Multi-

Year Integrated Grid Plan focus on upgrading generation and delivery infrastructure to expand capacity, support reliability and reduce congestion. Initiatives include targeted investments

and process improvements to harden the system, minimize service disruptions and enhance restoration response.

To avoid significant impacts from physical hazards, we implement infrastructure-hardening measures, such as the following:

• Storm-hardening efforts include installing a composite pole at approximately every fifth position, with more than 7,000 multi-layer composite poles deployed to enhance strength, flexibility and resiliency in high-risk areas.

• Lines in high-risk areas are being buried, and aging underground cables are upgraded with protective conduit to reduce outages from severe weather and enhance long-term system reliability.

• Aging wires are replaced with steel-reinforced aluminum conductors to increase strength and capacity for modern energy demands.

• Smart technology is integrated into new and upgraded substations to rapidly detect and isolate damage, speeding restoration.

• Animal guards and ruggedized equipment are installed to reduce outages caused by wildlife and environmental hazards.

• Advanced LineVue® ground-based inspection technology delivers a complete, high-precision view of subtransmission line conditions-up to 15 times more accurate than traditional methods-reducing outages and enabling precise, cost-effective decisions for line upgrades.

• Nearly 300 miles of overhead lines have been storm-hardened since 2019, and we continue to see them perform as expected and prevent cascading damage to the system.

  Disruption Minimization

  To reduce the severity of impacts from outage-inducing events, the following measures are implemented:

• Over 3,800 smart switches automatically reroute power during outages-preventing disruptions for over 750,000 customers and avoiding 120 million outage minutes since 2021.

• Voltage optimization equipment-including technologies such as voltage regulators, capacitor banks and automation

  systems-is deployed to ensure efficientpower delivery, reduce energy waste and support grid stability during disruptions.

• Added six static synchronous compensators (STATCOMs) in the St. Louis metro area since 2021 to enhance voltage stability and strengthen overall grid reliability.

  The strategic installation of composite poles, which are stronger than wood poles, help harden the grid by preventing cascading damage.

• Automated underground switchgear in high-risk areas enables faster fault location and restoration after cable failures.

• Proactively cleared vegetation along more than 13,375 miles of subtransmission and distribution lines-about 25% of the system-in 2025 to reduce outage risks from falling trees and branches.

• Drone teams inspect miles of power lines and equipment, enabling rapid identification of areas needing attention before and after storms, helping minimize outages and speeding restoration.

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Every three years, Ameren Missouri submits an Integrated Resource Plan (IRP) to the MoPSC, detailing strategies to meet projected customer demand over the next 20 years.

In February 2025, we updated our Preferred Resource Plan (PRP) originally set forth in the 2023 IRP. The PRP reflects the generation resource strategy for the IRP term, balancing

costs, risks, and environmental, customer and community impacts while ensuring reliability.

The PRP includes a diverse mix of natural gas, renewables, energy storage and infrastructure upgrades to strengthen grid resilience and meet anticipated demand growth. The PRP contemplates an additional 1.5 GW of new electric demand by 2032 and 2.5 GW by

2040, driven by business expansion and new large-load customers, including data centers. Meeting this demand with resilient, reliable energy requires dispatchable resources that can be called upon at any time to maintain system stability. Accordingly, Ameren plans to add two 800 MW natural gas simple-cycle energy centers by 2028 and 2,100 MW of

combined-cycle generation by 2031. Battery storage will also expand significantly, reaching 1,000 MW by 2030 and 1,800 MW by 2042,

enhancing flexibility and supporting a cleaner, more reliable energy future.

Ameren utilizes risk management measures to mitigate extreme weather impacts.

Spare transformers, switchgear and other critical equipment are stored at strategic locations. We also participate in transformer-sharing agreements and collaborate in the Midcontinent Independent System Operator's (MISO) transmission planning process.

These proactive steps strengthen resilience and enable rapid restoration.

Situational awareness is central to our approach. Our Watch Center tracks incidents and outages, supported by real-time weather data from independent providers, National Weather Service offices and a network of substation-based monitoring stations. The Transmission Operations Control Center (TOCC), opened in 2024, provides advanced monitoring and control during severe weather.

Ameren's Crisis Management Plan ensures a structured response. Using the Incident

Command System (ICS), a nationally recognized framework, we activate protocols during disruptive events, providing clear command and control. Readiness is reinforced through

orientations, workshops, tabletop exercises and full-scale drills involving all response teams and leadership.

To translate planning into action, Ameren deploys specialized resources and technologies that accelerate restoration and support community recovery, including:

• Mobile command center trailers equipped with high-speed internet, computer

  workstations, real-time communications and drone technology help coordinate large-scale restoration efforts.

• Participation in regional and national mutual assistance groups enables rapid mobilization of thousands of workers after major storms.

• Storm trailers stocked with restoration materials and mobile substations

  are maintained to quickly replace damaged infrastructure.

• An advanced outage management system provides real-time updates and prioritizes restoration for critical facilities, improving communication and efficiency.

• Partnerships with organizations like the United Way, the American Red Cross and local agencies deliver emergency repairs, housing and financial assistance after disasters.

Through these measures, Ameren demonstrates its commitment to resilience and reliability-ensuring that when outages occur, restoration is swift, coordinated and focused on supporting the communities we serve.

NOTE: Reductions are presented as of the end of the period indicated and based off 2005 levels. Wind and solar additions, energy center retirements by end of indicated year.

1. Ameren's goals encompass both Scope 1 and Scope 2 emissions, including other greenhouse gas emissions of methane, nitrous oxide and sulfur hexafluoride. This goal is dependent on a variety of factors, including cost-effective

advancements in innovative clean energy technologies, as well as constructive federal and state energy and economic policies. 4

STRENGTHENING RESILIENCE AND COMMUNITY RECOVERY: AMEREN'S STORM RESPONSE

Ameren's commitment to resilience was tested on May 16, 2025, when destructive EF-3 and EF-4 tornadoes struck the St. Louis metro area and parts of our Illinois service territory. The tornadoes and severe storms caused outages for nearly 280,000 customers, damaged approximately 1,000 poles and required replacement of more than 270 miles of distribution lines. Years of strategic investments in grid modernization, system hardening and emergency preparedness enabled Ameren to respond quickly and effectively, reducing

the impact on customers and communities. Purposeful upgrades-such as composite poles, smart switches and advanced monitoring-worked in tandem with rapid deployment strategies to speed restoration. Despite the unprecedented damage, Ameren's comprehensive storm response restored power to 60% of affected customers within 48 hours, and over 95% of impacted customers regained power within one week, underscoring the value

of proactive infrastructure investments in reducing outage duration and supporting community stability.

Ameren's response extended far beyond infrastructure. We immediately activated our comprehensive storm recovery initiative in partnership with local and national organizations, including United Way of Greater St. Louis, American Red Cross, The Salvation Army, Urban League of Metropolitan

St. Louis and the City of St. Louis Tornado Response Fund. By joining daily Community Organizations Active in Disaster (COAD) coordination calls, participating in biweekly Long-Term Recovery meetings, and shaping Disaster Case Management efforts with United Way, we ensured that support reached those most in need. The Metro St. Louis Community Voices Advisory Board, an engaged group of community representatives from multiple sectors, convened throughout the year to give voice to community priorities and inform how Ameren could best support these efforts. These alliances aligned resources to deliver critical services,

including relocation assistance, property cleanup, emergency repairs, temporary housing, food, clothing and transportation.

Ameren committed $1 million to relief efforts, including

$750,000 to community-based organizations and $250,000 for emergency assistance for impacted customers. This funding approach combined immediate support for established disaster-response agencies with competitive grants to

grassroots nonprofits addressing emerging needs such as mental health services, heirs' property issues and repairs for daycares and small businesses. Organizations like The Little Bit Foundation, College Hill Foundation, Gateway Children's Alliance, Forest ReLeaf and Legal Services of Eastern Missouri received targeted funding to meet these evolving challenges. Community engagement extended beyond financial aid. Ameren hosted three onsite bill assistance events in the hardest-hit zip codes, providing $306,000 in direct support and connecting more than 1,200 customers to additional programs, including weatherization services.

Ameren's collaborative approach demonstrates the importance of urgency, flexibility and sustained engagement. Ameren's holistic approach-combining infrastructure hardening, emergency preparedness, strategic partnerships, phased funding and community voice-offers a model

for resilience that prioritizes customer needs and ensures service continuity during severe weather events.

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Severe weather on May 16, 2025, swept through Ameren Missouri and Illinois service territories, bringing destructive tornadoes, strong winds and hail. In response, Ameren deployed 2,700 workers, including crews from neighboring states, to restore service to nearly 280,000 customers and rebuild infrastructure.

The Edison Electric Institute (EEI) honored Ameren with its Emergency Response Award for exceptional storm restoration efforts following the May 16 tornadoes.