Alliant Energy (LNT) FY2025 results: revenue $4.4 billion, up 9.6% on the year

Alliant Energy is a regulated investor-owned public utility holding company with its principal executive offices in Madison, Wisconsin. Its primary focus is providing regulated electric and natural gas service to approximately 1,010,000 electric and approximately 435,000 natural gas customers in the Midwest, through two public utility subsidiaries that are also its two reportable segments: IPL in Iowa and WPL in Wisconsin. It had 2,948 full- and part-time employees at the end of 2025, 1,705 of them in bargaining units, 1,003 at IPL and 992 at WPL.

IPL generates and distributes electricity and distributes and transports natural gas to retail customers in Iowa, supplying approximately 505,000 electric and 230,000 gas retail customers at the end of 2025, and it also sells electricity to wholesale customers in Illinois and Iowa. It provides utility services to incorporated communities as directed by the Iowa regulator, using non-exclusive franchises covering the use of public right-of-ways for a maximum term of 25 years. It had been generating and distributing steam for two customers in Cedar Rapids under contracts running through 2025, and exited the steam business after the year ended.

WPL does the same work in Wisconsin, supplying approximately 505,000 electric and 205,000 gas retail customers and selling electricity to wholesale customers in the state. It operates in municipalities under permits of indefinite duration and state statutes authorising utility operation in areas a municipality annexes.

What the utilities sell

Retail electricity sales were 25,122 thousand MWh in 2025, made up of 11,237 thousand MWh industrial, 7,393 thousand MWh residential and 6,492 thousand MWh commercial, with a further 2,565 thousand MWh sold wholesale and 5,386 thousand MWh in bulk power and other, for 33,129 thousand MWh in total. Retail customers numbered 1,009,387 at the end of the year. Maximum summer peak hour demand was 5,465 MW and maximum winter peak hour demand 4,433 MW.

Retail gas sales were 49,363 thousand dekatherms, with transportation and other volumes of 123,141 thousand, and 433,344 retail gas customers at year end.

The retail base spans several industries, with the largest concentrations in farming, agriculture, industrial manufacturing, chemicals including ethanol, pipeline transportation, packaging and food, and data centres. Wholesale customers are primarily municipalities and rural electric cooperatives. Electric sales are seasonal, with the annual peak normally in the summer months because of air conditioning, and a lesser effect in winter from heating.

Where the electricity comes from

The two utilities own a portfolio of generating units in Iowa, Wisconsin and Minnesota running on natural gas, renewable resources and coal. Of the 33,822 thousand MWh supplied in 2025, gas generation provided 12,440, coal 7,724, purchased wind 4,165 and other purchased power 1,121, with owned wind at 5,370 and solar at 2,811.

Retail electric customers in Iowa and Wisconsin cannot choose their electric supplier, and both utilities have an obligation to serve every retail customer in their territories. The filing says they nevertheless face competition from self-generation by large industrial customers, customer- and third party-owned generation such as solar panels, alternative energy sources, petitions to municipalise in Iowa and service territory expansions by municipal utilities through annexations in Wisconsin, and that the wholesale market is competitive against independent power producers, other utilities and MISO market purchases.

Both utilities must hold a planning reserve margin above their load at the time of the MISO-wide peak in each of four seasons. Required installed capacity reserve margins run from 15.0 percent for June to August 2026 up to 42.2 percent for December 2026 to February 2027. The filing says that from the planning period beginning 1 June 2028, MISO will implement a Direct Loss of Load methodology for capacity accreditation, incorporating forward-looking analysis and each resource's historical performance during periods of high system risk over the previous three years.

The filing says the mix of electric supply is expected to keep evolving with new renewable generation, energy storage facilities, new natural gas resources, refurbishing of existing wind farms, improvements at existing gas-fired units and the conversion of certain coal-fired units to natural gas. One project it names is a compressed carbon dioxide long-duration energy storage system of approximately 20 MW at WPL's Columbia Energy Center site, awarded up to approximately $30 million of Department of Energy grant funding in July 2024.

Outside the utilities

Non-utility holdings sit under AEF. They include a 16 percent ownership interest in ATC, an independent for-profit transmission-only company, held with a 20 percent interest in a related holding company; minority interests in regional and national venture funds; a 50 percent cash equity interest in a 225 MW wind farm in Oklahoma; the Sheboygan Falls Energy Facility, a 347 MW simple-cycle gas-fired unit near Sheboygan Falls, Wisconsin that is leased to WPL through 2044; Travero, a supply chain solutions company running a short-line rail freight service in Iowa, a Mississippi River barge, rail and truck freight terminal in Illinois, freight brokerage and a rail-served warehouse in Iowa; and various rail-served, ready-to-build manufacturing and industrial sites across the service territories.

From Alliant Energy's annual report on Form 10-K for the year ended 31 December 2025. The filing

Written from the 10-K filed 20 February 2026: read the full 10-K.