Northwest Natural Holding Co

NATURAL GAS DISTRIBUTION (NGD) SEGMENT

Both NW Holdings and NW Natural have one reportable segment, the NGD segment, which is operated by NW Natural. NGD provides natural gas service through approximately 806,000 meters in Oregon and southwest Washington. Approximately 88% of customers are located in Oregon and 12% are located in southwest Washington.

NW Natural has been allocated an exclusive service territory by the Oregon Public Utility Commission (OPUC) and Washington Utilities and Transportation Commission (WUTC), which includes the major population centers in western Oregon, including the Portland metropolitan area, most of the Willamette Valley, the Coastal area from Astoria to Coos Bay, and portions of Washington along the Columbia River. Major businesses located in NW Natural's service territory include retail, manufacturing, and high-technology industries.

Customers

The NGD business serves residential, commercial, and industrial customers with no individual customer accounting for more than 10% of NW Natural's or NW Holdings' revenues. On an annual basis, residential and commercial customers typically account for approximately 60% of NGD volumes delivered and approximately 90% of NGD margin. Industrial customers largely account for the remaining volumes and margin.

The following table presents summary meter information for the NGD segment as of December 31, 2024:

(1)NGD margin is also affected by other items, including miscellaneous revenues, gains or losses from NW Natural's gas cost incentive sharing mechanism, other margin adjustments, and other regulated services.

Generally, residential and commercial customers purchase both their natural gas commodity (gas sales) and natural gas delivery services from the NGD business. Industrial and some large commercial customers also purchase the gas commodity either from NW Natural or directly from a third-party gas marketer or supplier. Gas commodity cost is primarily a pass-through cost to customers; therefore, profit margins are not significantly affected by an industrial customer's decision to purchase gas from NW Natural or from third parties. Industrial and large commercial customers may also select between firm and interruptible service levels, with firm services generally providing higher profit margins compared to interruptible services.

To help manage gas supplies, tariffs are designed to provide some certainty regarding industrial and commercial customers' volumes by requiring an annual service election, special rates or possible restrictions for changes between elections.

We estimate natural gas was in approximately 63% of single-family residential homes in NW Natural's service territory in 2024. Customer growth in our region comes mainly from the following sources: single-family housing, both new construction and conversions; multifamily housing new construction; and commercial buildings, both new construction and conversions. Single-family new construction has consistently been our largest source of growth. Continued customer growth is closely tied to consumer preference for natural gas, the comparative price of natural gas to electricity and fuel oil, regulations and building codes permitting the use of natural gas in new construction and conversions, and the economic health of our service territory.

Competitive Conditions

In its service areas, the NGD business has no direct competition from other natural gas distributors. However, it competes with other forms of energy in each customer class. This competition among energy suppliers is based on price, efficiency, reliability, performance, preference, perceptions, market conditions, building codes, technology, federal, state, and local energy policy, and environmental impacts.

For residential and small to mid-size commercial customers, the NGD business competes primarily with providers of electricity, fuel oil, and propane.

In the industrial and large commercial markets, the NGD business competes with all forms of energy, including competition from wholesale natural gas marketers. In addition, large industrial customers could bypass NW Natural's natural gas distribution system by installing their own direct pipeline connection to the interstate pipeline system. NW Natural has designed custom transportation service agreements with several large industrial customers to provide transportation service rates that are competitive with the customer’s costs of installing their own pipeline.

Seasonality of Business

The NGD business is seasonal in nature due to higher gas usage by residential and commercial customers during the cold winter heating months. Other categories of customers experience similar seasonality in their usage but to a lesser extent.

Regulation and Rates

The NGD business is subject to regulation by the OPUC and WUTC. These regulatory agencies authorize rates and allow recovery mechanisms to provide the opportunity to recover prudently incurred capital and operating costs from customers, while also earning a reasonable return on investment for investors. In addition, the OPUC and WUTC also regulate the system of accounts and issuance of securities by NW Natural.

NW Natural files general rate cases and rate tariff requests periodically with the OPUC and WUTC to establish approved rates, an authorized return on equity (ROE), an overall rate of return (ROR) on rate base, an authorized capital structure, and other revenue/cost deferral and recovery mechanisms.

NW Natural is also regulated by the Federal Energy Regulatory Commission (FERC). Under NW Natural's Mist interstate storage certificate with FERC, NW Natural is required to file either a petition for rate approval or a cost and revenue study every five years to change or justify maintaining the existing rates for the interstate storage service.

For further discussion on our most recent general rate cases, see Part II, Item 7, "Results of Operations—Regulatory Matters—Regulation and Rates."

Gas Supply

NW Natural strives to secure sufficient, reliable supplies of natural gas to meet the needs of customers at the lowest reasonable cost, while maintaining price stability, managing gas purchase costs prudently and supporting our core value of environmental stewardship. This is accomplished through a comprehensive strategy focused on the following items:

•Reliability - ensuring gas resource portfolios are sufficient to satisfy customer requirements under extreme cold weather conditions;

•Diverse Supply - providing diversity of supply sources;

•Diverse Contracts - maintaining a variety of contract durations, types, and counterparties;

•Cost Management and Recovery- employing prudent gas cost management strategies; and

•Environmental Stewardship - striving to reduce the carbon content and environmental impacts of the energy we deliver.

Reliability

To support system reliability, the NGD business has developed a risk-based methodology in which it uses a planning standard to serve the highest firm sales demand day in any year with 99% certainty.

The projected maximum design day firm NGD customer sales is approximately 10 million therms. Of this total, the NGD business is currently capable of meeting approximately 55% of the requirements with gas from storage located within or adjacent to its service territory, while the remaining supply requirements would come from gas purchases under firm gas purchase contracts and recall agreements.

NW Natural segments transportation capacity, which is a natural gas transportation mechanism under which a shipper can leverage its firm pipeline transportation capacity by separating it into multiple segments with alternate delivery routes. The reliability of service on these alternate routes will vary depending on the constraints of the pipeline system. For those segments with acceptable reliability, segmentation provides a shipper with increased flexibility and potential cost savings compared to traditional pipeline service. The NGD business relies on segmentation of firm pipeline transportation capacity that flows from Stanfield, Oregon to various points south of Molalla, Oregon.

We believe gas supplies would be sufficient to meet existing NGD firm customer demand in the event of maximum design day weather conditions.

The following table shows the sources of supply projected to be used to satisfy the design day sales for the 2024-25 winter heating season:

The OPUC and WUTC have Integrated Resource Planning (IRP) processes in which utilities define different future scenarios and corresponding resource and compliance strategies in an effort to evaluate supply and demand resource and compliance requirements, consider uncertainties in the planning process and the need for flexibility to respond to changes, and establish a plan for providing reliable service while meeting carbon compliance obligations within frameworks that emphasize least cost and risk.

NW Natural generally files a full IRP biennially for Oregon and Washington with the OPUC and the WUTC, respectively, and files updates in Oregon between filings. The OPUC acknowledges NW Natural's action plan, whereas the WUTC provides notice that the IRP has met the requirements of the Washington Administrative Code. OPUC acknowledgment of the IRP does not constitute ratemaking approval of any specific resource acquisition strategy or expenditure. For additional information see Part II, Item 7, "Results of Operations—Regulatory Matters."

Diversity of Supply Sources

NW Natural purchases gas supplies primarily from the Alberta and British Columbia provinces of Canada and multiple receipt points in the U.S. Rocky Mountains to protect against regional supply disruptions and to take advantage of price differentials. For 2024, 60% of gas supply came from Canada, with the balance primarily coming from the U.S. Rocky Mountain region. We believe gas supplies available in the western United States and Canada are adequate to serve NGD customer requirements for the foreseeable future. NW Natural continues to evaluate the long-term supply mix based on projections of gas production and pricing in the U.S. Rocky Mountain region as well as other regions in North America.

NW Natural supplements firm gas supply purchases with gas withdrawals from gas storage facilities, including underground reservoirs and LNG storage facilities. Storage facilities are generally injected with natural gas during the off-peak months in the spring and summer, and the gas is withdrawn for use during peak demand months in the winter.

The following table presents the storage facilities available for NGD business supply:

(1)The Mist gas storage facility has a total maximum daily deliverability of 5.3 million therms and a total designed storage capacity of about 17.5 Bcf, of which 3.3 million therms of daily deliverability and 12.8 Bcf of storage capacity are reserved for NGD business customers.

(2)The North Mist facility is contracted to exclusively serve Portland General Electric, a local electric utility, and may not be used to serve other NGD customers. See "North Mist Gas Storage Facility" below for more information.

(3)The storage facility is located near Chehalis, Washington and is contracted from Northwest Pipeline, a subsidiary of The Williams Companies.

The Mist facility serves NGD segment customers and is also used for non-NGD purposes, primarily for contracts with gas storage customers, including utilities, third-party marketers, and electric generators. Under regulatory agreements with the OPUC and WUTC, gas storage at Mist can be developed in advance of NGD customer needs but is subject to recall when needed to serve such customers as their demand increases. When storage capacity is recalled for NGD purposes it becomes part of the NGD segment. As of May 1, 2024, 0.2 million therms per day of deliverability and 1.15 Bcf of associated non-utility Mist gas storage capacity was recalled to serve core customers. Customer rate increases related to this recall began on November 1, 2024. The North Mist facility is contracted for the exclusive use of Portland General Electric, a local electric utility, and may not be used to serve other NGD customers. See "North Mist Gas Storage Facility" below.

Diverse Contract Durations and Types

NW Natural has a diverse portfolio of short-, medium-, and long-term firm gas supply contracts and a variety of contract types including firm and interruptible supplies as well as supplemental supplies from gas storage facilities.

The majority of our gas supply contracts include year-round, winter-only, summer-only, and monthly baseload supplies, and daily spot purchases. We also maintain options to call on additional daily supplies during the winter heating season.

During 2024, a total of 822 million therms were purchased under contracts with durations as follows:

During 2024, there was one supplier that provided 10% or more of the NGD business gas supply requirements. No other individual supplier provided 10% or more of the NGD business gas supply requirements.

Gas Cost Management

The cost of gas sold to NGD customers primarily consists of the following items, which are included in annual Purchased Gas Adjustment (PGA) rates: gas purchases from suppliers; charges from pipeline companies to transport gas to our distribution system; gas storage costs; gas reserves costs; gas commodity derivative contracts; and renewable natural gas and its attributes, including renewable thermal certificates. Costs to comply with Washington's Climate Commitment Act (CCA) are included in the cost of gas for Washington customers. We expect that costs to comply with Oregon's Climate Protection Program (CPP) and any similar program that may be enacted in our service territory will also be included in the cost of gas.

The NGD business employs a number of strategies to mitigate the cost of gas sold to customers. The primary strategies for managing gas commodity price risk include:

•negotiating fixed prices directly with gas suppliers;

•negotiating financial derivative contracts that: (1) effectively convert floating index prices in physical gas supply contracts to fixed prices (referred to as commodity price swaps); or (2) effectively set a ceiling or floor price, or both, on floating index priced physical supply contracts (referred to as commodity price options such as calls, puts, and collars); and

•buying physical gas supplies at a set price and injecting the gas into storage for price stability and to minimize pipeline capacity demand costs.

NW Natural also contracts with an independent energy marketing company to capture opportunities regarding storage and pipeline capacity when those assets are not serving the needs of NGD business customers. Asset management activities provide opportunities for cost of gas savings for customers and incremental revenues for NW Natural through regulatory incentive-sharing mechanisms. These activities, net of the amount shared, are included in other for segment reporting purposes.

Gas Cost Recovery

Mechanisms for gas cost recovery are designed to be fair and reasonable, with an appropriate balance between the interests of customers and NW Natural. In general, natural gas distribution rates are designed to recover the costs of, but not to earn a return on, the gas commodity sold. Risks associated with gas cost recovery are minimized by resetting customer rates annually through the PGA and aligning customer and shareholder interests through the use of sharing, weather normalization, and conservation mechanisms in Oregon. See Part II, Item 7, "Results of Operations—Regulatory Matters" and "Results of Operations—Business Segment—Natural Gas Distribution Operations—Cost of Gas".

Environmental Stewardship

Part of our gas supply strategy is working to reduce the carbon content and the environmental impacts of the energy we deliver. To that end, NW Natural developed and implemented an emissions screening tool that uses Environmental Protection Agency (EPA) data to calculate the relative emissions intensity of gas producer operations and prioritize purchases from lower emitting producers. In 2019, we began using this emissions intensity screening tool alongside other purchasing criteria such as price, credit worthiness and geographic diversity. We view this as a cost-neutral way to reduce carbon emissions associated with our natural gas supply.

NW Natural is focused on taking steps to lower its emissions on behalf of customers by purchasing environmental attributes that are generated by the production of renewable natural gas (RNG). Under Oregon Senate Bill 98, NW Natural can purchase RNG or invest in RNG facilities, which generate these environmental attributes known as Renewable Thermal Certificates (RTCs). In 2019, the Washington State legislature also passed a bill supporting RNG procurement, House Bill 1257. The RTCs work like renewable energy certificates, or RECs, used in electricity markets. RTCs are verified and certifiedby the Midwest Renewable Energy Tracking System (M-RETS). The M-RETS Renewable Thermal Tracking System issues one RTC for every dekatherm of RNG injected into the gas system. NW Natural enters into contracts for the purchase of RNG and RTCs either through periodic request for proposals or through formal offerings or informal requests. See Part II, Item 7, "Results of Operations—Regulatory Matters".

In addition to purchases of RNG, NW Natural has piloted a hydrogen blend in pipelines serving its Sherwood Operations and Training Center. NW Natural has successfully tested a blend of up to 20% hydrogen. The tests met the safety protocols established by PHMSA Part 192. Additionally, NW Natural is focused on developing several hydrogen pilots for industrial and commercial customers to support their decarbonization goals.

NW Natural is subject to the requirements of the Washington CCA cap-and-invest program, and will be subject to Oregon's CPP. NW Natural has modeled pathways to compliance with the CCA and CPP in its most recent IRP. While costs associated with each possible compliance pathway differ, we intend to pursue recovery of the costs associated with these programs in rates.

Transportation of Gas Supplies

NW Natural's gas distribution system is reliant on a single, bi-directional interstate transmission pipeline to bring gas supplies into the natural gas distribution system. Although dependent on a single pipeline, the pipeline’s gas flows into the Portland metropolitan market from two directions: (1) the north, which brings supplies from the British Columbia and Alberta supply basins; and (2) the east, which brings supplies from Alberta as well as the U.S. Rocky Mountain supply basins.

NW Natural incurs monthly demand charges related to firm pipeline transportation contracts. These contracts have expiration dates ranging from 2025 to 2061. The largest pipeline agreements are with Northwest Pipeline. NW Natural actively works with Northwest Pipeline and others to renew contracts in advance of expiration to ensure gas transportation capacity is sufficient to meet customer needs.

Rates for interstate pipeline transportation services are established by FERC within the U.S. and by Canadian authorities for services on Canadian pipelines.

Gas Distribution

Safety and the protection of employees, customers, and our communities are, and will remain, top priorities. NW Natural constructs, operates, and maintains its pipeline distribution system and storage operations with the goal of ensuring natural gas is delivered and stored safely, reliably, and efficiently.

NW Natural has one of the most modern distribution systems in the country with no identified cast iron pipe or bare steel main. Since the 1980s, NW Natural has taken a proactive approach to replacement programs and partnered with the OPUC and WUTC on progressive regulation to further safety and reliability efforts for the distribution system. In the past, NW Natural had a cost recovery program in Oregon that encompassed programs for cast iron replacement, bare steel replacement, transmission integrity management, and distribution integrity management programs as appropriate.

Natural gas distribution businesses are likely to be subject to greater federal and state regulation in the future. Additional operating and safety regulations from the U.S. Department of Transportation’s Pipeline and Hazardous Materials Safety Administration (PHMSA) are currently under development. In January 2025, PHMSA released the final rulemaking: Gas Pipeline Leak Detection and Repair. The rulemaking includes congressional mandates from the PIPES (Protecting our Infrastructure of Pipelines and Enhancing Safety) Act of 2020 to reduce methane emissions from new and existing gas transmission, distribution, gathering, underground storage, and LNG facilities. The unpublished rulemaking was placed on a regulatory freeze by the new presidential administration and is expected to undergo additional review and amendment. In September 2023, PHMSA issued a notice of proposed rulemaking: Safety of Gas Distribution Pipelines and Other Pipeline Safety Initiatives. The proposed rulemaking requires operators to update distribution integrity management programs, emergency response plans, operations and maintenance manuals, and other safety practices. NW Natural does not foresee a significant impact of these rulemakings on our business given the modern materials used in our system.

North Mist Gas Storage Facility

The North Mist gas storage facility began operations in 2019. The North Mist facility provides long-term, no-notice underground gas storage service and is dedicated solely to Portland General Electric (PGE) under a 30-year contract with options to extend up to an additional 50 years upon mutual agreement of the parties. PGE uses the facility to fuel its gas-fired electric power generation facilities.

North Mist includes a reservoir providing 4.1 Bcf of available storage, a compressor station with a contractual capacity of 120,000 dekatherms of gas deliverability per day, no-notice service that can be drawn on rapidly, and a 13-mile pipeline to connect to PGE's Port Westward gas plants in Clatskanie, Oregon.

The facility is included in rate base under an established tariff schedule with revenues recognized consistent with the schedule. Billing rates are updated annually to the forecasted depreciable asset level and forecasted operating expenses.

There are additional expansion opportunities in the Mist storage field. Any expansion would be based on market demand, cost effectiveness, available financing, receipt of future permits, and other rights.