Northwestern Energy Group, Inc. · NASDAQ:NWE

Northwestern Energy — Form Energy — Investor Presentation (June 2025)

28 slides from Northwestern Energy's investor presentation, Jun 25, 2025

1. Slide 1: Breakthrough Low-Cost, Multi-Day Energy Storage

   BREAKTHROUGH LOW-COST, MULTI-DAY ENERGY STORAGE NorthWestern Energy ETAC June 25, 2025 Energy Storage For A Better World

2. Slide 2: Intro to Form Energy

   Intro to Form Energy © 2024 Form Energy CONFIDENTIAL 2

3. Slide 3: Form Energy Overview

   Form Energy Overview 150k ft^2 Somerville, MA LED BY ENERGY STORAGE VETERANS Decades of cumulative experience in energy storage 900+ ■ 100’s of MW of storage deployed Employees 87k ft^2 55 acres Bay Area, CA Weirton, WV OUR INVESTORS: LONG-TERM AND IMPACT-FOCUSED $1.2B+ in venture capital from top i

4. Slide 4: Rechargeable iron-air is the best technology for multi-day storage

   Rechargeable iron-air is the best technology for multi-day storage Form’s 100-Hour Reversible Rust Battery COST Lowest cost rechargeable battery chemistry. Chemistry entitlement <$1.00/kWh SAFETY No thermal runaway (unlike li-ion) Non-flammable aqueous electrolyte SCALE Iron is the most globally abun

5. Slide 5: What makes up a Form Energy system

   What makes up a Form Energy system Modular design enables easy scaling to GWh systems Cell Battery Module Enclosure Power Block System ~0.15 kW / 15 kWh ~4.5 kW / 450 kWh ~45 kW / 4,500 kWh ~2.9 MW / 290 MWh 10+ MW / 1000+ MWh ~1.37m x 0.94m x 70mm ~1.8m x 1m x 2.5m ~9.5’ x 8’ x 40’ <2 acres 5+ acre

6. Slide 6: Deployed enclosure / Battery module assembly

   Deployed enclosure Battery module assembly © 2024 Form Energy 6

7. Slide 7: Form Factory 1: U.S. Based Commercial-Scale Manufacturing

   Form Factory 1: U.S. Based Commercial-Scale Manufacturing Transforming Weirton Steel Land for Battery Manufacturing in West Virginia ■ Production Capacity: 500 MW / 50 GWh annually by 2028 ■ Trial Production Start: September 2024 ■ Commercial Production Start: 2025 Form Factory 1 site, June 2023 ■ T

8. Slide 8: Form Factory 1 commercial battery production has started

   Form Factory 1 commercial battery production has started Ramping to 50 GWh/yr manufacturing capacity by 2028 in Weirton, WV Summer 2024: new 500,000+ sq.ft facility built Fall 2024: Battery Manufacturing Started ■ <18 months from breaking ground to battery production ■ Semi-to-fully automated assemb

9. Slide 9: Over 13 GWh of announced multi-day storage projects

   Over 13 GWh of announced multi-day storage projects Broke ground Summer 2024 1.5 MW / 150 MWh 85 MW / 8500 MWh 1.5 MW / 150 MWh 10 MW / 1,000 MWh CO regulatory approval ✅ 5 MW / 500 MWh 10 MW / 1,000 MWh VA regulatory 10 MW / 1,000 MWh 15 MW / 1,500 MWh approval ✅ © 2024 Form Energy MN regulatory CO

10. Slide 10: Utilities and state agencies are calling for gigawatts of Multi-Day Storage

    Utilities and state agencies are calling for gigawatts of Multi-Day Storage in their future resource plans(1) PUC approves 10 MW project; IL developing 7.5 GW storage MI first to define Multi-Day Storage in ME collaborating on project Avista IRP selects 110 MW of State funds iron supply study programs

11. Slide 11: Multi-day Storage in NorthWestern's portfolio

    Multi-day Storage in NorthWestern’s portfolio © 2024 Form Energy CONFIDENTIAL 11

12. Slide 12: The Northwest region is vulnerable to multi-day reliability risks driven by weather

    The Northwest region is vulnerable to multi-day reliability risks driven by weather Example: January 2024, MLK Weekend Winter Storm Surge in wholesale market prices for 5 continuous days Emergency conditions declared for 48+ hours Western US Wholesale Energy Prices Energy emergencies declared by 4 B

13. Slide 13: NorthWestern Energy's 2023 IRP identifies a near-term need for long-duration resources

    NorthWestern Energy’s 2023 IRP identifies a near-term need for long-duration resources in the face of tightening grid conditions ■ 2023 IRP performs a “duration analysis” of grid Long-duration resources hedge WECC market scarcity and stress periods over 5 years of historical data, which gas supply ri

14. Slide 14: Multi-day storage is a low-cost energy reservoir

    Multi-day storage (MDS) is a low-cost energy reservoir – delivering firm capacity by shifting energy across days, months, and seasons Simulated annual operations of storage on NorthWestern Energy system Comparing stored energy in different 50 MW battery systems MDS can hold >10x the stored Deep disch

15. Slide 15: MDS delivers firm capacity across 100% of high grid stress hours

    Multi-day storage (MDS) delivers firm capacity across 100% of high grid stress hours in a way that other resources cannot Deliverability during NWE’s top 5% grid stress hours Example operations during NWE’s top 5% grid stress hours 2021 weather 43 hours 13 hours 4-10 hour storage is depleted during p

16. Slide 16: MDS protects NorthWestern from volatility in gas and power markets

    MDS protects NorthWestern from volatility in gas and power markets MDS hedges against price shocks at CIG gas hub MDS hedges against scarcity pricing at Mid-C power hub Example: Price Shock during Winter Storm Uri Mid-C Hub Scarcity Pricing Events, 2021-20242 Simulated operations of current portfoli

17. Slide 17: MDS enables NorthWestern to serve gas to more homes and businesses

    MDS enables NorthWestern to serve gas to more homes and businesses, by offsetting power sector gas consumption during periods of tight supply Gas supplies made available during peak usage days (3-day max of each month)1 from 50 MW storage projects on Northwestern Energy’s 2028 system During the cold

18. Slide 18: Iron-air wins on reliability, cost, safety, and speed to deploy

    Of all options to meet NorthWestern’s growing capacity needs, iron-air wins on reliability, cost, safety, and speed to deploy 100-hour Iron-air 4-hour Li-ion 8-hour Li-ion 10-hour Pumped Natural Gas Battery Battery Battery Hydro Storage CT Deliverability during grid 100%, subject to 100% 61% 78% 80%

19. Slide 19: Key considerations for utilities in planning and procurement

    Key considerations for utilities in planning and procurement © 2024 Form Energy CONFIDENTIAL 19

20. Slide 20: Utilities should facilitate fair consideration of long-duration / multi-day energy storage

    Utilities should facilitate fair consideration of long-duration / multi-day energy storage resources PLANNING Include MDS / LDES resources as options in utility modeling; model them correctly Consider extended time frames of grid stress events in Resource Adequacy RELIABILITY constructs, and conside

21. Slide 21: IRP modeling approaches must capture grid volatility and weather-driven risks

    IRP modeling approaches must capture grid volatility and weather-driven risks How does this benefit Best practices for capturing grid volatility How does this better grid customers? represent MDS? Model 8760 hour grid operations in capacity 1 expansion and production cost simulation Select least-cos

22. Slide 22: IRP modeling should recognize capacity accreditation benefits of multi-day storage

    IRP modeling should recognize the capacity accreditation benefits of multi-day storage relative to shorter duration resources Storage technologies with longer durations will keep a higher capacity accreditation, even while their penetrations increase © 2024 Form Energy CONFIDENTIAL 22 Source: Reserve

23. Slide 23: IRP tools must be configured to accurately simulate multi-day storage

    IRP tools must be configured to accurately simulate multi-day storage Simulated operations of 100-hour storage asset Aurora (default simulation settings) State of Charge Default simulation settings with 2-7 day look-ahead period result in little to no cycling of multi-day storage Conventional simulat

24. Slide 24: RFPs should be designed to recognize high-value deployments of long-duration storage

    RFPs should be designed to recognize high-value deployments of long-duration / multi-day storage Include fit-for-purpose bankability requirements that allow providers to demonstrate commercial track record, corporate, and technology backing. Consider all technology benefits, such as reliability, resil

25. Slide 25: RFP valuation frameworks should capture system-wide cost and benefits

    RFP valuation frameworks should capture the full spectrum of system-wide cost and benefits from deployment of MDS/LDES Holistic assessment of system-wide value Incomplete metrics which neglect system-wide value Avoided revenue requirement from 10 MW LCOS comparison between MDS and MDS project on PNW

26. Slide 26: Thank you!

    Thank you! Mark Thompson Kailash Raman Senior Director, State Affairs Commercial Analytics Manager mthompson@formenergy.com kraman@formenergy.com 30 Dane St. Somerville, MA 02143 1 (844) 367-6462 info@formenergy.com www.formenergy.com © 2023 Form Energy CONFIDENTIAL 26

27. Slide 27: Appendix

    Appendix © 2024 Form Energy CONFIDENTIAL 27

28. Slide 28: Assessing the value of MDS via Formware modeling of NWE system

    Assessing the value of MDS via Formware modeling of NWE system Key Data Inputs Modeling Framework ■ Most system assumptions aligned with NWE 2023 IRP: ■ Modeled of NWE’s 2028 planned portfolio – Candidate resource types and costs in Formware1 – Existing and planned resource attributes ■ Simulated po

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