NiSource signs Microsoft to 1,100 MW of Indiana data center power
NiSource signed a 20-year deal on 16 October to power Microsoft's Indiana data center campus from 2028, adding about 1,100 MW to a shared pool Microsoft pays for. The only named plant is a 600 MW battery that is not binding until two contracts are signed by 31 January.
WIRE · HYPERSCALERS · US · Data as at 17 Oct 2026
NiSource said on 16 October 2026 that it has signed a 20-year energy agreement with Microsoft for its northwest Indiana data center campus, adding about 1,100 MW to the power pool its generation arm runs for big data center customers. Service starts in 2028 and Microsoft pays for all the generation and transmission it needs. The only plant named so far is a 600 MW battery that a developer signed for the day before, and it does not take effect until two more contracts are in place. On the hyperscalers layer, the price is agreed. What is still open is what actually stands behind the 1,100 MW.
What happened
16 October 2026 · NiSource release
Microsoft signs for 20 years from 2028; the pool grows by about 1,100 MW
Signed through NiSource Generation Company (GenCo). Microsoft fully funds the generation and transmission needed to serve its load. Inside Indiana Business places the campus in La Porte
15 October 2026 · Form 8-K
A 600 MW, 2,400 MWh battery on a 20.5-year toll, about $2.2 billion of payments
AGP Group builds, owns and runs it on the MISO grid. GenCo pays a fixed storage rate, buys the power that charges it, and keeps the market revenue. First phase expected by 1 December 2027
The condition
No construction contract and grid hookup by 31 January 2027, no toll
AGP Group must sign an engineering and construction contract and an interconnection agreement it is satisfied with. NiSource also lists regulatory approval as a risk
The savings claim
Expected savings for existing customers rise from $1.4 billion to about $1.75 billion
Over the life of all its data center contracts, or up to $140 per customer a year. More detail is promised on the third-quarter call on 28 October
Why cash cares
This is the third big data center customer on the same machine. Amazon came first. In June the Indiana regulator signed off on Amazon's contract for up to 2,400 MW of load by 2032 and on the plants GenCo is building for it: two 1,300 MW gas plants at the Schahfer station and a 400 MW battery, 3,000 MW in all. An Alphabet subsidiary's contract was approved in July. Microsoft now joins a shared pool rather than getting plants of its own.
That pool changes who decides what gets built. NiSource's filings describe a portfolio that NIPSCO, the local utility, picks and dispatches for all the big customers together, made up of plants GenCo builds, batteries it rents and capacity it buys. Amazon got named plants. Microsoft, so far, has one named battery.
The battery terms show what that kind of power costs. Our arithmetic, not a NiSource figure: $2.2 billion over 20.5 years on 600 MW is about $107 million a year, or roughly $15 per kW a month, before the adjustments the contract allows. NiSource expects to book it as a finance lease, so it counts as a debt-like obligation, and GenCo has an option to buy the battery outright along the way.
Figure: Amazon got plants. Microsoft gets a pool. Named resources for each contract and the dates the Microsoft supply depends on.
The second-order read
Who gets paid. AGP Group, which collects the fixed storage payments for two decades whether the battery is busy or not. GenCo, which earns on the pool it runs; Blackstone Infrastructure holds 19.9% of GenCo's parent, issued for $35.2 million in cash in October 2025. NIPSCO, whose transmission system gets upgraded on Microsoft's money. Then whoever supplies the cells, inverters and transformers, not yet named.
Who carries the risk. Microsoft, on paper, since it funds everything it needs. GenCo in practice: it signs the toll, pays for the electricity that charges the battery and owns the gap if the pool runs short.
Who waits. Microsoft's campus. Service starts in 2028, but the one named resource does not exist yet and its contract is not binding.
Stuck step. The battery's construction contract and its interconnection agreement with MISO, both due by 31 January 2027, about 106 days from today (our arithmetic). Behind that sits a Microsoft special contract the Indiana regulator still has to approve. The release gives no filing date for it.
Two cautions
The 1,100 MW is pool capacity, not load. Amazon needed 3,000 MW of plants for 2,400 MW of load under MISO's reserve rules, a ratio of 1.25. If the same ratio held, 1,100 MW would back about 880 MW of Microsoft load. That is our arithmetic as an illustration only; NiSource has not given a load figure.
NiSource has not said whether the battery counts toward the 1,100 MW. If it does, it is about 55% of it, and a four-hour battery cannot carry a campus that runs all day on its own. The rest has to be gas, other plants or capacity bought in the market, and none of it is named.
What would change the view
- A NIPSCO filing at the Indiana regulator with the Microsoft special contract and a list of the plants behind it.
- AGP Group signing its construction contract and interconnection agreement before 31 January, which makes the toll binding.
- A FERC filing to cover NIPSCO and GenCo serving Microsoft, like the ones filed in August for Amazon and Alphabet.
What to watch
- NiSource's third-quarter call on 28 October, where it promised operational and financial details on the deal.
- Gas turbine or capacity purchases by GenCo that would fill the unnamed part of the pool.
- Microsoft's next quarterly results, for its capital spending and lease commitments.
Read: What does Microsoft do?, Indiana approves AES plan to power Google's 390 MW Monrovia data center, and Meta named behind $10B Kentucky data center needing 2.2 GW of power
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Not investment advice. Do your own research. The yearly and per-kW battery cost, the 106 days, the 1.25 ratio, the 880 MW illustration and the 55% share are our arithmetic from the documents and reports below.
References
- NiSource, "NiSource announces long-term agreement with Microsoft expected to increase customer savings and support Indiana's economic growth", 16 Oct 2026. The 20-year term from 2028, about 1,100 MW, Microsoft funding, the 600 MW battery and the $1.75 billion savings.
- NiSource Inc., Form 8-K, Item 2.03, Battery Storage System Tolling Agreement with Atlas Storage 1 LLC, filed 16 Oct 2026. The 600 MW / 2,400 MWh toll, $2.2 billion, 20.5 years, 1 Dec 2027, the 31 Jan 2027 conditions and the purchase option.
- Indiana Utility Regulatory Commission, Order in Cause No. 46362, 17 Jun 2026. Amazon's 2,400 MW by 2032, the 3,000 MW of plants and the Schahfer and Mitchell sites.
- NiSource Inc., Form 10-Q for the quarter ended 30 June 2026, Aug 2026. Alphabet contract approval, the pool structure, the August FERC filings and the 19.9% Blackstone stake.
- NiSource, "NiSource to release third quarter 2026 financial results and host conference call on October 28", Oct 2026. The 28 October call date.
- Inside Indiana Business, "NiSource, Microsoft ink deal to power La Porte data center campus", 16 Oct 2026. The La Porte campus location.
- The Duck Curve, "NiSource tolls a 600 MW, 2,400 MWh battery alongside Microsoft deal", 16 Oct 2026. Context on the pool and on what the release leaves unnamed.
