Power Moves: Data center growth pushes four utilities toward a larger grid buildout

Power companies have been scrambling to meet data center demand across the U.S., and a series of utility reports last week paint a picture of how shovels in the ground on projects have reshaped their buildout of electric capacity. 

Data center demand is moving into construction sites, electric service agreements and multibillion-dollar power plans across four regulated utility companies, extending the infrastructure buildout from Pennsylvania and Wisconsin to Arizona and Montana.

November disclosures from PPL Corp., WEC Energy Group, Pinnacle West Capital Corp. and NorthWestern Energy Group Inc. report data center projects at stages ranging from preliminary studies to operating facilities, along with plans for additional generation and transmission.

“This represents a significant milestone for Invitium Energy and an important step toward converting strong customer demand into tangible generation projects,” PPL President and CEO Vincent Sorgi said in the company’s Nov. 6 earnings release. Invitium, PPL’s joint venture with Blackstone Infrastructure, is proposing generation for a Pennsylvania data center.

• NorthWestern Energy’s Montana opportunities include Atlas Power, with a study load starting at 75 megawatts and ramping to 150 MW, and Quantica Infrastructure, starting at 25 MW and ramping to 1,100 MW. Targeted starts are late 2027 and early 2029, respectively. Both remain under development agreements. NorthWestern says large-load customers in Montana would be served from its overall utility portfolio, which has surplus capacity beginning in 2026. Utilities Avista and Puget Sound Energy transferred their stakes in Units 3 and 4 of the Colstrip coal plant to NorthWestern, adding 592 MW at no acquisition cost, effective Dec. 31, 2025. NorthWestern says the Avista interests advance its regulated portfolio to resource adequacy, while the combined interests support large-load integration. It also reports significant interest in South Dakota. Customers requiring new generation in either state would be expected to provide credit support during construction.

• Pinnacle West’s utility subsidiary, Arizona Public Service, reports 5.8 gigawatts of committed load across customer categories, including more than 15 data center sites. About 4.9 GW remains unserved. More than 90 percent of committed load in the manufacturing and data center segments is in various construction phases, including planning. APS separately identifies roughly 20 GW of uncommitted opportunity. Its resource plan projects annual electricity needs more than doubling by 2041, with manufacturing and data centers driving most incremental growth, and identifies roughly 15 GW of new resources and 2.6 GW of transmission capacity.

• WEC Energy Group’s Wisconsin segment expects 4.9 GW of additional electric demand from 2026 through 2031, about a 60 percent increase. That includes 3.2 GW associated with Microsoft and southeastern Wisconsin, 1.3 GW with Oracle and 400 MW of other growth. Microsoft’s first site began operations in April. At Port Washington, Vantage Data Centers has four buildings under construction for the OpenAI and Oracle Stargate expansion. WEC says Oracle has met required financial security obligations. The campus has potential for up to 3.5 GW over time, above the 1.3 GW forecast through 2031.

• PPL’s Pennsylvania data center pipeline reached 35.3 GW in advanced planning, including 11.4 GW under signed electric service agreements and 8.5 GW under construction. In Kentucky, its utilities report 14.7 GW of economic development opportunities through 2032, including 12.8 GW from data centers. About 2.3 GW of the 14.7 GW Kentucky economic development pipeline is covered by signed reimbursement agreements, up 1 GW from the prior quarter. PPL assigns projects representing about 4 GW of additional Kentucky peak demand through 2032 a probability of success of at least 50 percent.

PPL’s Pennsylvania growth directly affects PJM, while WEC’s Wisconsin expansion falls within MISO’s regional system. NorthWestern’s South Dakota development process includes Southwest Power Pool screening and network studies.

PJM said in September that it had begun reviewing large-load requests for its 2027 forecast under updated guidelines intended to better assess whether projects will materialize. PJM retained Charles River Associates as an independent consultant. The firm presented its data center forecast to PJM’s Load Analysis Subcommittee on Nov. 2. CRA’s scenarios tested assumptions about AI adoption, efficiency, power availability, infrastructure and supply-chain constraints.

PJM says its generation and transmission planning depends on forecasts that account for the scale and timing of new customer demand.

MISO identifies rising large loads as a reason to coordinate transmission, generation and resource adequacy planning. It has accelerated generation interconnection through its Expedited Resource Addition Study and transmission reviews through the MISO Transmission Expansion Plan’s Expedited Project Review.

MISO’s large-load integration framework calls for real-time telemetry, the ability to curtail demand and coordination of resource adequacy as large customers expand. It lists non-firm service and a step-up to firm service as solutions under its objective of scaling loads with network upgrades. At its Aug. 12 Large Load Working Group meeting, MISO requested stakeholder feedback on its Flexible Large-Load Interconnections and Transmission Service proposal.

Invitium, in which PPL holds a 51 percent ownership share, has agreed to key commercial terms for approximately 2 GW of generation supporting QTS’s Salem Township project. Invitium’s term sheet is nonbinding and subject to conditions. Fuel cells and batteries could arrive as early as 2029; combined-cycle gas units are expected in 2032 and 2033.

The generation venture sits outside PPL’s regulated utility investment plan. Its proposed 20-year initial arrangement would include a fixed monthly payment, with annual escalation, covering return of and on invested capital and fixed operating costs. Variable payments would be made when the plants operate, covering fuel and other variable operating costs. PPL describes the structure as providing a “regulated-like risk profile.”

WEC cites Oracle’s security obligations, NorthWestern expects construction credit support for new generation, and PPL says its approved large-load tariffs are designed to make customers causing incremental infrastructure needs bear the associated costs. APS’s rate case proposes direct assignment of generation costs to extra-high-load-factor customers. Under WEC’s very large customer tariff, a customer terminating service early pays the remaining net book value of assets to the extent they cannot be repurposed.

WEC’s $47.5 billion capital plan for 2027-2031 is $10 billion larger than its 2026-2030 plan, including an $8.4 billion increase in generation investment. APS says transmission expansion could drive more than $6 billion of cumulative investment through 2035. PPL’s $25 billion plan for 2027-2030 includes another combined-cycle unit supporting Kentucky large-load growth.

The filings support a continuing, geographically broad buildout, with the clearest evidence in projects already operating, under construction or backed by service agreements. NorthWestern’s development agreements and APS’s uncommitted opportunities remain less certain than PPL’s construction figures or Microsoft’s operating site.

Further evidence of the buildout’s strength will come as additional customers secure service, post financial support, break ground and take electricity. The four companies’ investment plans prepare for that demand over several years. Generation and transmission delivery dates will help determine how quickly the campuses behind those plans can expand.