Avista Corporation · NYSE:AVA
Avista — 2027 Electric and Natural Gas IRP Technical Advisory Committee Meeting No. 10
77 slides from Avista's conference presentation, May 27, 2026
Slide 1: 2027 Electric and Natural Gas Integrated Resource Plans TAC Meeting No. 10 Agenda
DRAFT 2027 Electric and Natural Gas Integrated Resource Plans Technical Advisory Committee Meeting No. 10 Agenda Wednesday, May 27, 2026 Virtual Meeting – 9:00 am to 12:00 pm Pacific Time Topic State Audience • Introduction and Questions from TAC 9 o Proposed Idaho Natural Gas Energy Efficiency • CE
Slide 2: Introductions 2027 Electric & Gas Integrated Resource Planning
DRAFT Introductions 2027 Electric & Gas Integrated Resource Planning TAC 10 – May 22, 2026 John Lyons, Ph.D. – Senior Resource Policy Analyst
Slide 3: TAC 10 Agenda
DRAFT TAC 10 Agenda • Introduction and Questions from TAC 9 • Proposed Idaho Natural Gas Energy Efficiency • CEIP Update • CETA Interim Energy Compliance Report • Building Electrification Impact on T&D System • Load Forecast Update (Energy & Peak) • New Resource QCC Forecast 2
Slide 4: Meeting Guidelines
DRAFT Meeting Guidelines • IRP team is in office Monday – Wednesday; also available by email, phone and Teams for questions and comments • Stakeholder feedback responses shared with TAC at meetings, in Teams and in Appendix • Working IRP data posted to Teams • All TAC meetings will be virtual on Tea
Slide 5: Virtual TAC Meeting Reminders
DRAFT Virtual TAC Meeting Reminders • Please mute mics unless speaking or asking a question • Raise hand or use the chat box for questions or comments • Respect the pause • Please try not to speak over the presenter or a speaker • Please state your name before commenting for the note taker • This is
Slide 6: Idaho Natural Gas Energy Efficiency
DRAFT Idaho Natural Gas Energy Efficiency TAC 10 – May 27, 2026 James Gall, Manager of Resource Analysis
Slide 7: Background and Proposal
DRAFT Background and Proposal • On June 1, 2026, Avista plans to file a request to discontinue natural gas energy efficiency (EE) programs in Idaho due to lack of cost effectiveness, with an effective date of September 1, 2026. • Due to this, it raises the question of whether the IRP should include
Slide 8: Idaho Energy Efficiency Supply Curve
DRAFT Idaho Energy Efficiency Supply Curve Supply Curve (UCT) $100 $90 Load Impact with Energy Efficiency • 2029 Load Change is -0.4% $80 • 2047 Load Change is -1.8% $70 $60 $ per Dekatherm 2 yr $50 20 yr $40 Avoided Cost $30 225,500 Dth $20 38,000 Dth $10 $0 0 500,000 1,000,000 1,500,000 2,000,000
Slide 9: TAC 11 Technical Modeling Workshop – Rescheduling, TBD
DRAFT TAC 11 Technical Modeling Workshop – Rescheduling, TBD Topic State Audience PRiSM Model Tour All E&G Aurora Resource Adequacy Model Tour WA/ID Electric New Resource Cost Model All E&G TAC 12 Wednesday, July 15, 2026 (13:00 – 16:00 PDT) Topic State Audience Load & Resource Balance Methodology W
Slide 10: TAC 13 – Monday, August 17, 2026
DRAFT TAC 13 – Monday, August 17, 2026 (13:00 – 16:00 PDT) Topic State Audience ETO Energy Savings OR Gas Preferred Resource Strategy Results All E&G Oregon Non-Pipe Alternatives OR Gas IRP/Progress Report Outlines All E&G Next Steps All E&G 9
Slide 11: TAC 14 – Thursday, September 17, 2026
DRAFT TAC 14 – Thursday, September 17, 2026 (13:00 – 16:00 PDT) Topic State Audience Portfolio Scenario Analysis All E&G Avoided Cost All Electric Resource Adequacy Results WA/ID Electric CBI Forecast and Results/Energy Burden WA/OR E&G Final Report Overview and Comment Plan All E&G Action Items All
Slide 12: Other Key 2027 IRP Dates
DRAFT Other Key 2027 IRP Dates • Oct 15, 2026 – Draft Electric IRP Released to TAC • Nov TBD 2026 – Virtual Public Meeting • Noon-1pm • 6-7pm • Jan 1, 2027 – Final Electric IRP Filed • Feb 15, 2027 – Draft Gas IRP Released to TAC • Apr 1, 2027 – Final Gas IRP Filed 11
Slide 13: Clean Energy Transformation Act Update
DRAFT Clean Energy Transformation Act Update Integrated TAC Meeting #10 May 27, 2026 Kelly Dengel | Clean Energy Policy & Implementation Manager
Slide 14: 2026 Clean Energy Compliance Report & 2025 Clean Energy Implementation Plan
DRAFT 2026 Clean Energy Compliance Report (2021 CEIP) & 2025 Clean Energy Implementation Plan 2
Slide 15: 2026 Clean Energy Compliance Report
DRAFT 2026 Clean Energy Compliance Report 2021 CEIP’s 2022 – 2025 Implementation Period DRAFT – DATA IS NOT FINAL 3
Slide 16: 2021 CEIP Timeline
DRAFT 2021 CEIP Timeline CEIP Approval BCEIP Approval 38 Conditions File 2 Conditions File File 2021 CEIP 2023 BCEIP 2026 Compliance Report 2023 Progress 2024 Progress 2025 Progress 2026 Progress Report Report Report Report June 23, 2022 Nov. 1, 2023 March 22, 2024 Nov. 1, 2021 July 1, 2023 July 1,
Slide 17: Compliance Report Requirement Summary
DRAFT Compliance Report Requirement Summary ▪ Demonstrate “whether & how” meet interim in & specific targets ▪ Demonstrate specific actions contributed the clean energy standards, provided customer benefit & were cost effective ▪ Demonstrate equitable transition through Customer Benefit Indicators (
Slide 18: Renewable Energy Targets & Specific Actions
DRAFT Renewable Energy Targets & Specific Actions Approved Interim Targets Specific Actions 2022 – 40% ▪ Retire sufficient RECs to comply with annual targets 2023 – 47.5% 2024 – 55% 2025 – 62.5% 6
Slide 19: Renewable Energy Targets & Availability (MWh)
DRAFT Renewable Energy Targets & Availability (MWh) Available (MWh) 2022 2023 2024 2025 Average Renewable Energy MWh 3,502,810 3,263,436 3,493,661 3,931,342 3,547,812 Renewable Energy % 59.4% 59.1% 61.9% 67.0% 62.5% Target (MWh) 2022 2023 2024 2025 Average Renewable Energy Target MWh 2,275,197 2,624
Slide 20: Renewable Energy Additional Specific Actions
DRAFT Renewable Energy Additional Specific Actions Specific Actions Status ▪ Secure 48 aMW from the 2020 Chelan PUD PPA’s: Renewable RFP or 2022 All Source RFP ▪ 10-year for 51 aMW thru 2033 ▪ 20-year for 51 aMW for 2026-2030, increasing to 102 aMW for 2031-2045 ▪ Issue 2022 All Source RFP for 48 aM
Slide 21: Energy Efficiency Targets & Specific Actions
DRAFT Energy Efficiency Targets & Specific Actions Approved Targets Specific Actions Year Biennium Actual ▪ Existing Programs (9) Target MWh* MWh 2022-2023 107,260 60,409 ▪ New Programs (8) ▪ Equity Advisory Group Identified Projects 2024-2025 66,543 85,207 ▪ Wood Stove Replacement Incentive Total 1
Slide 22: Energy Efficiency Targets
DRAFT Energy Efficiency Targets Energy Efficiency (MWh) 2022 2023 2024 2025 Total Energy Efficiency Target* 53,322 53,322 33,272 33,272 173,188 Energy Efficiency Achieved** 23,020 37,389 45,018 40,189 145,616 “Although Avista failed to meet its conservation targets, we find that there existed suffic
Slide 23: Demand Response Targets & Specific Actions
DRAFT Demand Response Targets & Specific Actions Approved Targets Specific Actions 30 MW of DR savings ▪ 30 MW Large Industrial DR Contract 2022-2031 ▪ Time of Use & Peak Time Rebate Pilot Demand Response MW 2022 2023 2024 2025 Total Demand Response Target 30 MW 30 MW Demand Response Achieved 30 MW
Slide 24: Demand Response Additional Specific Actions
DRAFT Demand Response Additional Specific Actions Specific Actions Status ▪ Commercial EV Time of Use Rate Implemented Commercial TOU in 2021 Design phase started in 2025. Estimated ▪ Spokane Tribe Microgrid Partnership construction completion in January 2028. ▪ Connected Communities Project Reduced
Slide 25: Incremental Costs
DRAFT Incremental Costs Cost Cap 2022 2023 2024 2025 Total Incremental Cost Cap Estimate $44.4 $36.0 $24.9 $13.0 $118.3 Incremental Cost 2022 2023 2024 2025 Total Incremental Cost Estimate* $2.8 $3.2 $10.2 $25.4 $41.6 Incremental Cost Actual $3.3 $6.9 $16.6 $22.1 $49.0 *Based on proposed renewable t
Slide 26: Discussion & Questions
DRAFT Discussion & Questions 14
Slide 27: 2025 Clean Energy Implementation Plan
DRAFT 2025 Clean Energy Implementation Plan 2025’s CEIP’s 2026 – 2029 Implementation Period 15
Slide 28: 2025 CEIP Planning with Advisory Group Collaboration
DRAFT 2025 CEIP Planning with Advisory Group Collaboration Incorporated UTC Meeting 2025 2025 CEIP Publish comments & filed All-Party & Approval IRP & CEAP Advisory Group 2025 Draft CEIP 2025 CEIP Discussions March 9 Sept. 2023 – January July October Nov. 2025 March Dec. 2024 – July 2025 2025 2025 –
Slide 29: 2025 Clean Energy Implementation Plan
DRAFT 2025 Clean Energy Implementation Plan Interim & Specific Targets | Specific Actions | Additional Actions & Goals Public Named Communities & Participation Customer Benefit Indicators Plan Renewable Energy Demand Company Energy Efficiency Response Initiatives 17
Slide 30: 2025 – 2027 Public Participation Plan
DRAFT 2025 – 2027 Public Participation Plan Participation Strategies ▪ Virtual public meetings ▪ CEIP webpage improvements ▪ Quarterly email newsletter ▪ Increase multi-language access ▪ Equity Advisory Group ▪ Educational, testimonial videos ▪ Community events ▪ Targeted paid social media ▪ Biennia
Slide 31: Named Communities
DRAFT Named Communities Condition: Identify Deepest Need Avista Electric Residential Households (as of Q4 2024) 245,564 2021 CEIP 2025 CEIP Washington State Department of Health (DOH) V1 2019 V2 2022 Highly Impacted & Vulnerable Populations* 105,867 134,720 Federal Climate & Economic Justice 40 Map
Slide 32: 2025 Customer Benefit Indicators
DRAFT 6 Equity Areas | 13 CBIs | 54 Metrics 2025 Customer Benefit Indicators Condition: Data Normalization Energy Energy Environmental Public Affordability Accessibility Health Resilience Security Affects Participation in Outreach & Energy Availability Generation Outdoor Air Employee Diversity Compa
Slide 33: Renewable Energy Targets
DRAFT Renewable Energy Targets 100.0% Approved 2026 – 2029 CEIP 90.0% 80.0% Approved 2022 – 2025 CEIP Percent of Washington 70.0% Retail Load 60.0% 50.0% 80.0% 76.5% 40.0% 73.0% 69.5% 66.0% 62.5% 55.0% 30.0% 47.5% 40.0% 20.0% 10.0% 0.0% 2022 2023 2024 2025 2026 2027 2028 2029 2030 21
Slide 34: Renewable Energy Interim Targets & Specific Actions
DRAFT Renewable Energy Interim Targets & Specific Actions Interim Targets Specific Actions 2026 – 66.0% ▪ Retire sufficient RECs to comply with annual targets 2027 – 69.5% 2028 – 73.0% Status 2029 – 76.5% ▪ Ongoing 22
Slide 35: Renewable Energy Additional Actions
DRAFT Renewable Energy Additional Actions Additional Actions Status ▪ Issue 2025 All Source RFP ▪ RFP contract negotiations ▪ 75 – 375 MW of winter qualifying capacity ▪ Battery Energy Storage System – 100 MW ▪ 50 – 350 MW of summer qualifying capacity ▪ Natural Gas CT – Efficiency upgrade & 14 MW ▪
Slide 36: Energy Efficiency Specific Targets & Specific Actions
DRAFT Energy Efficiency Specific Targets & Specific Actions Specific Target Specific Actions 155,712 MWhs* savings by 2029 ▪ Continue existing cost-effective measures/programs ▪ Pursue CPA identified cost-effective measures/programs Condition: EE Target Status ▪ Ongoing *Subject to 2025 CPA & 2026-2
Slide 37: Demand Response Specific Targets & Specific Actions
DRAFT Demand Response Specific Targets & Specific Actions Specific Targets Specific Actions Cumulative 55 MW of DR savings ▪ Continue 30 MW industrial demand response contract during a single peak hour by 2029 ▪ Pursue cost-effective solutions from All-Source RFP Condition: DR RFP Filing Status ▪ RF
Slide 38: Demand Response Additional Actions
DRAFT Demand Response Additional Actions Additional Actions Status Time of Use Rate & Peak Time Rebate Pilot ▪ Pilots end Q2 2026, with filing due December 1, 2026 EV Time of Use Rate ▪ Will conduct demand response potential assessment NEEA End-Use Load Flex Project ▪ Phase 2 study approved with reg
Slide 39: Named Communities Investment Fund
DRAFT Named Communities Investment Fund Additional Action $5M Annually $2M $3M Energy Efficiency Community Watch NCIF Stories https://www.youtube.com/playlist?list=PLhTj-kwTtfCBVRQSDNyVLNfhvui9u8dI_ 27
Slide 40: Conditions & Status
DRAFT Conditions & Status Conditions | 12 Status Named Communities | 2 Conditions ▪ Identify “Deepest Need” ▪ In progress, subcommittee created ▪ Identify programs and allocation amount for "Deepest Need" ▪ Contract with Empower Dataworks Customer Benefit Indicators | 4 Conditions ▪ Co-develop CBI d
Slide 41: Conditions & Status
DRAFT Conditions & Status Conditions | 12 Status Specific Targets/Actions & Incremental Cost | 6 Conditions ▪ Update DR target & specific actions after RFP contracts signed ▪ Contracts in negotiation ▪ 2027 IRP accelerated clean energy scenario & issue RFP ▪ In progress ▪ Update incremental cost in
Slide 42: Discussion & Questions
DRAFT Discussion & Questions 30
Slide 43: T&D Costs of Building Electrification
DRAFT T&D Costs of Building Electrification TAC 9 – May 27, 2026 Robert Hughes Resource Planning Analyst
Slide 44: What makes up this cost?
DRAFT What makes up this cost? Incremental increases in demand due to building electrification will require additional investments in the transmission and distribution system beyond traditional load growth. Estimated to be $304 per kW-yr (compared to $316 kW-yr in the 2025 IRP). Costs (2025$) includ
Slide 45: Load Forecast Update
DRAFT Load Forecast Update TAC 10 – May 27, 2026 Mike Hermanson – Power Supply Analyst
Slide 46: Transition End Use Model to Load Forecast
DRAFT Transition End Use Model to Load Forecast Energy Forecast Peak Forecast • Starts with Avista’s medium term (5-year) • Estimate 2025 weather adjusted peak load forecast. using regression analysis built on historical temperatures and loads. • Continues past five years using growth • Estimate of
Slide 47: Energy Forecast
DRAFT Energy Forecast 2045 2025 IRP – 1,349 aMW 2027 IRP w/EE – 1,493 aMW 2027 IRP w/o EE – 1,588 aMW 2025 IRP AAGR – 0.88% 2027 IRP AAGR (w/ EE) – 1.34% 2027 IRP AAGR (w/o EE) – 1.62% *adjusted for industrial customer that is no longer a customer 3
Slide 48: Energy Forecast
DRAFT Energy Forecast EV AAGR – 17.9% Native Load AAGR – 0.59% • EV load contributes significantly to load growth 4
Slide 49: Energy Forecast
DRAFT Energy Forecast Washington Load AAGR – 1.63% 2050 Load Forecast (aMW) WA – 1,040 ID – 530 Idaho Load AAGR – 0.83% • Higher load growth in Washington is driven by EVs. 5
Slide 50: Peak Forecast
DRAFT Peak Forecast 3,094 MW 2,863 MW Winter Forecast AAGR – 1.59% Summer Forecast AAGR – 2.02% • Forecasted acceleration of peak growth from past trends 6
Slide 51: Peak Forecast
DRAFT Peak Forecast Winter Forecast AAGR – 1.59% Summer Forecast AAGR – 2.02% Winter Forecast w/o EVs AAGR – 0.79% Summer Forecast w/o EVs AAGR – 1.28% 7
Slide 52: Peak Forecast
DRAFT Peak Forecast Summer 2027 AAGR – 2.0% Winter 2027 AAGR – 1.6% Summer 2027 w/o EE AAGR – 1.79% Winter 2027 w/o EE AAGR – 2.14% Summer 2025 IRP* – 0.89% Winter 2025 IRP* – 0.87% *adjusted for industrial customer that is no longer a customer 8
Slide 53: 2025 IRP to 2027 IRP Load Forecast - Drivers of Growth
DRAFT 2025 IRP to 2027 IRP Load Forecast - Drivers of Growth • The peak baseline utilized in the forecast was established with a new methodology – a trend of the last 20 years rather than a rolling average of the last 20 years. This increased the summer baseline and was carried through the forecast.
Slide 54: Load Forecast Update
DRAFT Load Forecast Update TAC 10 – May 27, 2026 Michael Brutocao – Natural Gas Planning Manager
Slide 55: Transition End Use Model to Load Forecast
DRAFT Transition End Use Model to Load Forecast Year Load Forecast Peak Day Forecast Avista’s 2026 Peak 2026 Peak Day Forecast 2026 Day Forecast → YOY growth rate of For each of Avista’s service Avista’s medium-term, Avista’s medium-term territories, daily loads are 5-year forecast monthly load fore
Slide 56: Oregon – Load Forecast
DRAFT Oregon – Load Forecast Compound Annual Growth Rate 2028 - 2045 2028 - 2050 -0.52% -0.49% -1.66% -1.68% -1.40% Historical values are reflective of forecasted rate schedules only 3 2025 IRP EE trended for years beyond 2045
Slide 57: Klamath Falls – 2026 Peak Day Forecast
DRAFT Klamath Falls – 2026 Peak Day Forecast 4 Historical data since 2005
Slide 58: Klamath Falls – Peak Day Forecast
DRAFT Klamath Falls – Peak Day Forecast Compound Annual Growth Rate 2028 - 2045 2028 - 2050 -0.39% -0.36% -1.42% -1.46% -1.41% 5 2025 IRP EE trended for years beyond 2045
Slide 59: La Grande – 2026 Peak Day Forecast
DRAFT La Grande – 2026 Peak Day Forecast 6 Historical data since 2005
Slide 60: La Grande – Peak Day Forecast
DRAFT La Grande – Peak Day Forecast Compound Annual Growth Rate 2028 - 2045 2028 - 2050 -0.40% -0.37% -1.54% -1.56% -1.42% 7 2025 IRP EE trended for years beyond 2045
Slide 61: Medford – 2026 Peak Day Forecast
DRAFT Medford – 2026 Peak Day Forecast 8 Historical data since 2005
Slide 62: Medford – Peak Day Forecast
DRAFT Medford – Peak Day Forecast Compound Annual Growth Rate 2028 - 2045 2028 - 2050 -0.40% -0.38% -1.43% -1.46% -1.39% 9 2025 IRP EE trended for years beyond 2045
Slide 63: Roseburg – 2026 Peak Day Forecast
DRAFT Roseburg – 2026 Peak Day Forecast 10 Historical data since 2005
Slide 64: Roseburg – Peak Day Forecast
DRAFT Roseburg – Peak Day Forecast Compound Annual Growth Rate 2028 - 2045 2028 - 2050 -0.39% -0.36% -1.39% -1.41% -1.36% 11 2025 IRP EE trended for years beyond 2045
Slide 65: Idaho – Load Forecast
DRAFT Idaho – Load Forecast Compound Annual Growth Rate 2028 - 2045 2028 - 2050 0.89% 0.94% 0.64% 0.70% 0.10% Historical values are reflective of forecasted rate schedules only 12 2025 IRP EE trended for years beyond 2045
Slide 66: Idaho – 2026 Peak Day Forecast
DRAFT Idaho – 2026 Peak Day Forecast 13 Historical data since 2012
Slide 67: Idaho – Peak Day Forecast
DRAFT Idaho – Peak Day Forecast Compound Annual Growth Rate 2028 - 2045 2028 - 2050 0.93% 0.96% 0.67% 0.74% 0.03% 14 2025 IRP EE trended for years beyond 2045
Slide 68: Washington – Load Forecast
DRAFT Washington – Load Forecast Compound Annual Growth Rate 2028 - 2045 2028 - 2050 -0.85% -0.80% -1.34% -1.31% -2.32% Historical values are reflective of forecasted rate schedules only 15 2025 IRP EE trended for years beyond 2045
Slide 69: Washington – 2026 Peak Day Forecast
DRAFT Washington – 2026 Peak Day Forecast 16 Historical data since 2012
Slide 70: Washington – Peak Day Forecast
DRAFT Washington – Peak Day Forecast Compound Annual Growth Rate 2028 - 2045 2028 - 2050 -0.83% -0.79% -1.32% -1.22% -2.00% 17 2025 IRP EE trended for years beyond 2045
Slide 71: New Resource QCC Forecast
DRAFT New Resource QCC Forecast TAC 10 – May 27, 2026 Jon Lee, Resource Planning Analyst
Slide 72: Avista's Qualified Capacity Credit Methodology
DRAFT Avista’s Qualified Capacity Credit Methodology • Avista utilizes the Western Power Pool’s WRAP assigned QCCs in developing our Load and Resources report, but we also conduct a separate validation process to accurately assess those values. • For new resources, Avista will use generic estimates
Slide 73: WRAP QCC Determination
DRAFT WRAP QCC Determination • Includes only binding participants and their associated load and resources • Loss of load events (LOLE) tabulated during seasonal hours • Pure capacity (no outages) added in all hours until the program footprint (or subregion) reached 0.1 LOLE • Monthly adjustments mad
Slide 74: Future Penetration of VERs
DRAFT Future Penetration of VERs Wind - Winter 20% 18% 16.4% 16.1% 15.0% • Future penetrations of 3 GW, 6 GW, and 15% 13.8% Seasonal QCC 9 GW studied for Wind, Solar and ESR 13% 8.7% VER Zones/Subregions 10% 8.5% 7.9% 7.3% 8% • 0.1 LOLE analysis performed again 5% ESR - Summer under each incremental
Slide 75: WRAP-Based QCC for Certain New Resources
DRAFT WRAP-Based QCC for Certain New Resources Winter (Jan) Summer (Aug) Resource 2028 2035 2045 2028 2035 2045 Geothermal/Nuclear 95.0% 95.0% 95.0% 95.0% 95.0% 95.0% Biomass 97.3% 97.3% 97.3% 97.3% 97.3% 97.3% CCCT 101.3% 101.3% 101.3% 88.0% 88.0% 88.0% Frame Machine 103.4% 103.4% 103.4% 89.8% 89.8
Slide 76: E3 Reliability Assessment
DRAFT E3 Reliability Assessment Reliability Contribution by Resource Type (2025) • Driven by loss of load events occurring Enhanced Geothermal 95% primarily during wintertime multi-day Small Modular Nuclear Reactor 94% low hydro conditions Gas + CCS 93% • Each resource was measured based on Natural
Slide 77: Impact of Increased VER Penetration
DRAFT Impact of Increased VER Penetration ELCCs come from E3’s 96% GHG Reduction Scenario includes 28 GW wind and 13 GW solar by 2035, 63 GW wind and 62 GW solar by 2045 7 Energy + Environment Economics (E3): Resource Adequacy and the Energy Transition in the Pacific Northwest – March 2026
Avista — 2027 Electric and Natural Gas IRP Technical Advisory Committee Meeting No. 10 on 6ix