Steam and Air-Conditioning Supply (District Energy) — NAICS 221330

An investor primer for both public-market and private investors. Core industry figures are U.S. federal statistics; company- and system-level facts come from company filings and industry sources, labeled throughout. Reported facts are separated from forward-looking judgments in the wording.

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1. Overview

This is the district energy business. Instead of every building running its own boiler and chiller, a central plant makes steam, hot water, or chilled water and pipes it underground to many buildings — a downtown, a university, a hospital campus, a military base. The customer buys heating and cooling as a metered utility service and skips the capital and upkeep of on-site equipment.

Two things make it interesting to investors. First, each system is a local natural monopoly: once the pipes are in the street, no one builds a second competing grid, so cash flows are stable, contracted, and often inflation-linked. Second, the industry is in a decarbonization capital cycle — old fossil-fired plants are being swapped for electric boilers, heat pumps, and thermal storage, and new "thermal energy network" laws let utilities build networked-geothermal systems and earn a regulated return. The catch for stock pickers: there is no pure U.S. public-equity play. Public investors get only diluted exposure through a diversified utility; the real owners are infrastructure funds, universities, hospitals, and municipalities. This primer covers both routes in.

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2. What it is and how it's structured

NAICS 221330 — Steam and Air-Conditioning Supply covers establishments that provide steam, heated air, or cooled air, including steam distributed through mains [1]. It sits inside Industry Group 2213 ("Water, Sewage and Other Systems") in Sector 22 ("Utilities") of the North American Industry Classification System (NAICS). Mapped activities include district heating (steam distribution), chilled-water and cooled-air distribution, and geothermal steam produced for heating [1].

What the code excludes (and where those activities live instead):

• Electric power generation — 221111 through 221118 (hydro, fossil, nuclear, solar, wind, geothermal-for-electricity, biomass, other) and electric power distribution — 221121/221122. If a plant's primary product is electricity, it is coded to electric power even when it also sells steam [1]. This is the single biggest reason the measured industry looks small (see §3).
• Natural gas distribution — 221210 (piped gas to customers) [1].
• Water supply — 221310 and sewage treatment — 221320, the sibling codes in the same group [1].
• Plumbing, Heating, and Air-Conditioning Contractors — 238220, and HVAC equipment wholesalers and makers (423730, 333415, 333414) — firms that install, sell, or build equipment inside one building rather than supply thermal energy over a network [1]. This is the most-confused boundary: 221330 is a utility that sells the heat, not a contractor that installs a furnace.

A classification key: NAICS follows an establishment's primary production process. A university or hospital central plant is usually counted with its parent institution (education, 611310; hospitals, 622110), and most government-owned systems are excluded from the business statistics entirely [1]. That is why the statistical industry is far smaller than the installed physical base.

Ownership mix. The sector splits four ways:

• One rate-regulated investor-owned utility (IOU) of scale: Consolidated Edison runs the largest U.S. district-steam utility — the only meaningful listed exposure.
• Private "merchant" platforms owned by infrastructure funds: Vicinity Energy, Cordia, and CenTrio.
• Universities and hospitals that own their own campus plants — the largest group by number of systems, and the least captured in the official statistics.
• Municipal, cooperative, and federal/military city and base systems make up the rest [7][20][21].

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3. How big it is

Lead with our authoritative federal statistics for NAICS 221330. These capture the separately organized thermal-utility industry — mostly private, stand-alone systems.

The 2022 Economic Census itself counted a close 122 establishments, 1,980 employees, and $225.3 million of payroll [2]. Either way this is a tiny, capital-intensive utility niche: roughly $21 million of revenue per firm and ~$11 million per establishment (calculated) [2][3]. Pay is high — on the order of $115,000 on average (2023 payroll divided by employment), consistent with a skilled utility-operations workforce [3].

Read these numbers as an undercount. Federal business statistics understate district energy for two structural reasons. (1) Integrated utilities code steam to their primary line. The entire state of New York shows only about $28 million of 221330 revenue in the 2022 Economic Census [2] — because Con Edison's combined electric/steam operation is classified under electric power, not 221330. For scale, Con Edison's steam operation alone booked $703 million of revenue in 2025 [9]. (2) Campus and institutional systems at universities, hospitals, and military bases are coded to education, health care, or government [1].

The real footprint is better seen physically. The measures below are broader, older, and non-Census — keep them separate from the $1.26 billion figure above:

• ~660 operating U.S. district-energy systems serving 5.45 billion square feet (ft²) of heating and 1.88 billion ft² of cooling floorspace, on a fuel mix ~74% natural gas — U.S. Energy Information Administration (EIA), published 2018 using 2012 data [6].
• 281 of those systems (43%) include combined heat and power (CHP) — plants that make electricity and capture the waste heat — totaling more than 6,700 megawatts (MW) of electric capacity and roughly 30 million megawatt-hours (MWh) a year, per the U.S. Department of Energy (DOE) [7].
• On the customer side, about 86,000 commercial buildings (6.75 billion ft²) used district heat in 2018 and spent $4.303 billion on it — EIA Commercial Buildings Energy Consumption Survey (CBECS). Because this includes captive campus plants, it is not comparable to the $1.26 billion Census figure [8].

Con Edison's NYC steam network — the largest in the world, operating since 1882 — moves about 27 billion pounds of steam a year through roughly 106 miles of mains to about 1,490 customers in Manhattan [9][12].

Honest gap: no single current federal dataset gives total active U.S. systems, capacity, ownership split, and fuel mix at once. The 2012 EIA/DOE inventory is the best physical baseline and should be read as dated.

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4. The investable universe

There are essentially no pure public plays. The table shows the listed names with any exposure; the meaningful ownership is private.

Public / listed exposure (all indirect except ConEd's steam segment):

¹ Approximate: ~$112 share price × shares outstanding, mid-2026 [29]. For KKR, Antin, and ENGIE, district energy is a look-through sliver, not ownership of the cash flows. No U.S.-listed exchange-traded or closed-end fund offers meaningful pure-play exposure.

Major private / institutional owners (where the value actually sits):

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5. How the money works

District energy earns money three ways, depending on regulation.

A. Rate-regulated model (Con Edison steam). A state-regulated utility earns an allowed return on equity (ROE) on its rate base (its net invested capital). The playbook is simple: grow the rate base by investing in plant and pipes, and earn the authorized ROE on it. For Con Edison steam, the New York Public Service Commission (NY PSC) set the authorized ROE at 9.25%, but the segment actually earned only 6.65% in the 12 months to December 2025 — it under-earns its allowed return [10][11]. Net steam plant (a proxy for rate base) was about $2.0 billion, and steam capital spending is rising from roughly $105–113 million a year today toward a forecast $200 million+ later this decade [9][10]. Fuel costs are largely passed through; the 2025 average price was about $41.53 per thousand pounds (Mlb) of steam [9]. Rate cases are contested: in its November 2025 filing ConEd asked for a 9.90% ROE, and state staff countered at 9.3% — regulators routinely cut requests [11].

B. Merchant / contract model (Vicinity, Cordia, CenTrio, campus P3s). These operators are generally not price-regulated. They sell under long-term (often 20–50-year) energy-service agreements, typically structured as a fixed capacity/demand charge (which recovers plant and network capital) plus a commodity charge (which passes through fuel and electricity). For example, nonprofit District Energy St. Paul's 2025 heating tariff charged $6.44 per kilowatt per month for demand plus $28.73 per MWh for energy; cooling was $34.19 per ton per month plus $0.093 per ton-hour [19]. Contracts often add take-or-pay minimums, inflation escalators, and connection charges. The best assets pair long tenor, full commodity pass-through, and creditworthy anchors (hospitals, universities) with room to add nearby customers cheaply.

C. Campus concession / public-private partnership (P3). A private operator pays a large upfront sum to finance, modernize, and run an institution's utilities under a 40–50-year deal, earning an availability-style fee for meeting performance targets [17].

CHP and power markets. Where a plant has CHP, it can sell electricity behind the meter, under a power purchase agreement (PPA), to a utility as a Public Utility Regulatory Policies Act (PURPA) qualifying facility (QF), or into a capacity market — capturing the "spark spread" while reusing waste heat [23]. EPA puts CHP whole-system efficiency at 60–80% [28]. A thermal-only plant has no inherent power-market revenue.

Tax credits. The Inflation Reduction Act (IRA) makes CHP, geothermal, and thermal-storage property eligible for the federal investment tax credit (ITC) under Section 48/48E — a 6% base rate rising to 30% with prevailing-wage and apprenticeship compliance [22]. Crucially, tax-exempt owners (universities, hospitals, municipalities) can monetize the credit via elective ("direct") pay — a cash refund — which materially improves campus and public decarbonization economics [22]. The production tax credit (PTC) under Section 45Y rewards clean electricity, not thermal sales, so fossil CHP should not be modeled as broadly PTC-eligible [22].

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6. What drives demand

1. Decarbonization mandates. New York City's Local Law 97 (LL97) caps carbon on large buildings [25], and Boston's Building Emissions Reduction and Disclosure Ordinance (BERDO) charges $234 per metric ton of excess CO₂-equivalent [26]. These push building owners toward clean thermal supply — a tailwind for decarbonized district energy, a headwind for fossil systems that don't clean up.
2. Urban density and campus growth — district energy is most economic where thermal load is dense: downtowns, universities, medical centers [6].
3. Reliability and resilience — central plants with redundancy and the ability to "island" during a grid outage appeal to hospitals, data centers, and critical facilities [7].
4. Cooling growth — hotter summers, data centers, and labs raise chilled-water demand; thermal storage shifts electric peaks (Austin Energy shifted 169 MW off-peak in fiscal 2025) [20].
5. Waste-heat reuse — recovering heat from data centers, sewers, and industry feeds next-generation low-temperature networks [31].
6. Avoided in-building capital — customers offload boiler/chiller capital and maintenance to the operator [6].

Headwind: Con Edison projects its steam peak demand to fall ~0.9% per year over five years as buildings get more efficient [9]. Warm winters, office vacancy, and on-site heat pumps all erode legacy heating volume.

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7. Regulation

• State public utility commissions (PUCs) regulate rates and service for steam/thermal utilities where they are treated as public utilities — most visibly the NY PSC over Con Edison steam (Case 22-S-0659), and the Missouri PSC over Vicinity's Kansas City steam tariff [11][32]. Merchant/contract systems are largely not price-regulated; they run on negotiated contracts and franchises but remain subject to safety and environmental rules.
• Federal Energy Regulatory Commission (FERC) matters only when a CHP plant sells electricity for resale, interconnects to the grid, or takes QF status (Form 556). Thermal service itself is not a FERC-regulated product [23].
• U.S. Environmental Protection Agency (EPA) — Clean Air Act rules drive fuel-switching and emissions-control spending on fossil plants: New Source Review (NSR), Title V operating permits, Boiler MACT (maximum achievable control technology), and greenhouse-gas reporting for facilities above 25,000 metric tons of CO₂-equivalent [24].
• Nuclear Regulatory Commission (NRC) — not applicable today; nuclear generation is out of scope (NAICS 221113), and U.S. nuclear district heating is negligible. NRC would matter only if a future project drew heat from a licensed reactor [30].
• New "thermal energy network (TEN)" laws — a regulated growth avenue. New York's Utility Thermal Energy Network and Jobs Act (UTENJA, 2022) requires large gas utilities to pilot networked geothermal; roughly 12 pilots totaling ~$880 million are in development [27]. Washington, Maryland, and Vermont passed enabling laws in 2024, and Eversource's Framingham, Massachusetts pilot is live [27]. These let utilities rate-base thermal networks — a structural expansion of the regulated version of this industry.

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8. Competitive dynamics and consolidation

Local monopoly, national fragmentation. The measured industry is highly concentrated: the top 4 firms hold 69.4% of revenue, the top 8 hold 82.4%, the top 20 hold 94.6%, and the top 50 hold 99.9% (2022 Economic Census; the concentration index is suppressed) [4]. With only 59 firms nationally, it is effectively an oligopoly of local monopolies — each system a natural monopoly in its service area [2][4]. Competition happens in three places, not under the same street: at initial connection (district service versus a building's own equipment), at contract renewal (stay connected versus pay to bypass), and for the market (funds bidding to buy a system or win a concession).

Infrastructure capital is driving consolidation. Long-life, inflation-linked, contracted cash flows make district energy a favored infrastructure asset class. Recent deals (valuations reported; not clean earnings multiples, because portfolios often span assets outside 221330):

• Antin bought Veolia's U.S. district-energy business for a $1.25 billion enterprise value (EV) in 2019 (~3.1× the ~$400M revenue), rebranded it Vicinity, and ran a sale process in 2025 [14].
• KKR bought Clearway's thermal business for ~$1.9 billion in 2021, relaunching it as Cordia [15].
• Brookfield sold its North American district-energy platform for ~$4.1 billion aggregate EV (Canadian and U.S. assets, separate buyers) in 2021 [18].
• Campus P3s: Ohio State ($1.015 billion upfront plus a $150M academic commitment, 2017), University of Iowa ($1.165 billion upfront, 2020), Syracuse (CenTrio, $245 million plus $118M modernization), Duquesne ($102M plant plus $50M distribution) [17]. These are politically sensitive but transfer decarbonization risk and capital to specialist owners.

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9. Risks

• Decarbonization capital and stranded-asset risk. Fossil-fired steam plants face mandatory conversion to electric boilers, heat pumps, and storage. Con Edison's steam segment already under-earns its allowed return (6.65% actual vs. 9.25% authorized), showing the earnings strain of a capital-heavy, price-sensitive service [10].
• Customer bypass and volume decline. Cheaper building-level heat pumps let customers leave, spreading fixed costs over fewer units — the classic "fixed-cost spiral." Efficiency, office vacancy, and warm winters compound it [9].
• Rate and contract risk. PUCs can cut requested returns and capex; merchant systems face renewal and franchise risk [11].
• Interest-rate and leverage sensitivity. Infrastructure owners run high leverage against long-dated cash flows; higher rates compress valuations and refinancing capacity.
• Aging infrastructure. Century-old mains (NYC's system dates to 1882) carry maintenance, safety, and reliability liabilities [12].
• Customer concentration. One university, hospital, or a few landlords can represent most of a system's load.
• Execution risk on new models. Networked-geothermal and TEN pilots are early-stage, capital-intensive, and unproven at scale [27].

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10. How to invest, and the outlook

Two ways in.

Public-market investors have only diluted, indirect options. Consolidated Edison (NYSE: ED) is the closest listed exposure to regulated district steam, but steam is only ~4% of a diversified electric-and-gas utility. At the $112.37 close on July 17, 2026, on 2025 earnings per share of $5.66 and a $3.55 annual dividend, ED traded at about 19.9× trailing earnings (price-to-earnings, P/E) and a 3.16% dividend yield (calculated); its value tracks allowed ROE, rate-base growth, and interest rates — not steam per se [9][29]. KKR, Antin, and ENGIE give only manager/sponsor exposure, not the asset cash flows [14][15][17]. Bottom line: no pure public play exists.

Private-market investors are the natural owners. Infrastructure funds — Antin, KKR, QIC, Ullico, Meridiam, Axium — buy platforms for stable, contracted, inflation-linked cash flows, typically at high multiples of earnings before interest, taxes, depreciation and amortization (EBITDA); Vicinity's 2019 EV was $1.25 billion [14]. Other routes: direct ownership/operation of a city or campus system; campus P3 concessions (50-year leases with large upfront payments, e.g. ~$1.165 billion at the University of Iowa) [17]; municipal or project bonds for a fixed-income route; and the emerging regulated TEN channel (~$880 million of New York pilots) as a future avenue for utility investors [27]. Underwrite each asset on its own contract tenor, take-or-pay terms, fuel pass-through, customer credit and concentration, pipe age and deferred maintenance, decarbonization capex, and terminal value under declining fossil-heat demand — not as a generic utility.

Outlook (judgment). Expect a slow-growing core with a decarbonization capital supercycle. Underlying thermal volumes are roughly flat to slightly declining, but capital intensity per system is rising sharply as operators replace fossil boilers with electric boilers, river/sewer heat pumps, and thermal storage. Con Edison targets net-zero-aligned steam by 2050 and has cut direct steam emissions ~60% since 2005 [12]; Vicinity's 42-MW "eSteam" electric boiler went live in 2024, with a 35-MW river heat pump due ~2028 and storage by 2031 [13]. The upside optionality is real — building-performance mandates (LL97, BERDO), IRA tax credits with direct pay for tax-exempt owners, thermal-energy-network rate-basing, and data-center waste-heat reuse [22][25][26][27]. So are the risks — stranded fossil assets, customer bypass, rate compression, and rate-sensitive valuations. Either way, M&A will stay active, because infrastructure capital views decarbonizing district energy as an attractive, if niche, long-duration asset [14][15].

Note on the industry-size figure: the ~$53 billion global district-heating market often quoted in trade press is a broader, worldwide measure dominated by Europe, China, and the Nordics [31]; the U.S. is a small share of it, and the authoritative U.S. figure remains the 2022 Economic Census receipts of ~$1.26 billion [2].

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Sources

1. U.S. Census Bureau / OMB, North American Industry Classification System — 221330 Steam and Air-Conditioning Supply (2022) (definition, scope, adjacent codes 221111–221122, 221210, 221310, 221320, 238220, 423730, 333415, 333414; classification by primary process). https://www.census.gov/naics/?input=221330&year=2022&details=221330
2. U.S. Census Bureau, 2022 Economic Census — Utilities Summary Statistics (EC2222BASIC), NAICS 221330, United States (receipts $1,263,307k; 59 firms; 122 establishments; 1,980 employees; $225,293k payroll; state detail). https://data.census.gov/table/ECNBASIC2022.EC2222BASIC
3. U.S. Census Bureau, County Business Patterns 2023, NAICS 221330 (118 establishments; 1,957 employees; $229,998k annual payroll). https://www.census.gov/programs-surveys/cbp.html
4. U.S. Census Bureau, 2022 Economic Census — Concentration Ratios, NAICS 221330 (CR4 69.4%, CR8 82.4%, CR20 94.6%, CR50 99.9%; HHI suppressed; 59 firms). https://www.census.gov/programs-surveys/economic-census.html
5. U.S. Small Business Administration, Table of Small Business Size Standards (NAICS 221330 = $30.0M average annual receipts). https://www.sba.gov/document/support-table-size-standards
6. U.S. Energy Information Administration / ICF / IDEA, U.S. District Energy Services Market Characterization, 2018 (2012 data: 660 systems; 5.451B ft² heating, 1.878B ft² cooling; ~74% natural gas). https://www.eia.gov/analysis/studies/buildings/districtservices/pdf/districtservices.pdf
7. U.S. Department of Energy, CHP Technology Fact Sheet: District Energy Systems, 2020 (281 systems with CHP; 6,700+ MW; ~30M MWh). https://www.energy.gov/sites/default/files/2021/03/f83/District_Energy_Fact_Sheet.pdf
8. U.S. Energy Information Administration, 2018 Commercial Buildings Energy Consumption Survey (CBECS) (~86,000 buildings / 6.745B ft² used district heat; $4.303B expenditure; ~55,000 buildings used district chilled water). https://www.eia.gov/consumption/commercial/data/2018/
9. Consolidated Edison, Inc., Form 10-K FY2025 (steam revenue $703M; operating income $5M; 16.975B lb delivered; $41.53/Mlb; ~106 miles of mains; ~1,490 customers; net steam plant $2,009M; steam ≈4.2% of $16.918B consolidated revenue; steam peak demand ~-0.9%/yr). https://www.sec.gov/cgi-bin/browse-edgar?action=getcompany&CIK=0001047862&type=10-K
10. Consolidated Edison, Inc., Form 10-K FY2024–FY2025 (steam authorized ROE 9.25%, actual 6.65% for 12 months ended 12/31/2025; steam capex rising from ~$105–113M toward $200M+). https://www.sec.gov/cgi-bin/browse-edgar?action=getcompany&CIK=0001047862&type=10-K
11. New York State Public Service Commission, Con Edison Steam Rate Plan, Case 22-S-0659 (9.25% ROE, 48% equity ratio); 2025 steam rate filing (9.90% requested vs. 9.3% DPS staff). https://dps.ny.gov/pending-and-recent-electric-rate-cases
12. Con Edison / International District Energy Association (IDEA) and Wikipedia, New York City steam system (largest system; since 1882; ~106 miles of mains; ~27B lb/yr; direct emissions down ~60% since 2005; net-zero-aligned 2050 target). https://en.wikipedia.org/wiki/New_York_City_steam_system
13. Vicinity Energy, Company overview / eSteam™ launch (~19 systems, 12 cities; 200M+ ft²; 400+ MW CHP; 42-MW electric boiler online 2024; 35-MW river heat pump ~2028; storage 2031). https://www.vicinityenergy.us/
14. Antin Infrastructure Partners / ION Analytics, Acquisition of Veolia's U.S. district energy (2019, $1.25B EV; ~$400M revenue; ~3.1× revenue) and 2025 Vicinity sale process. https://en.wikipedia.org/wiki/Vicinity_Energy
15. KKR / Clearway Energy / Cordia, KKR acquires Clearway thermal business (~$1.9B, 2021), relaunched as Cordia; ~17 systems, 700+ customers; $165M Essential Utilities bolt-on (2026). https://cordiaenergy.com/about-us/
16. QIC / Ullico / CenTrio, QIC and Ullico Complete Acquisition of CenTrio (formerly Enwave USA; 400+ buildings; ~170 employees; Chicago, Houston, Los Angeles, New Orleans, Seattle, Portland, Denver, Syracuse). https://www.prnewswire.com/news-releases/qic-and-ullico-complete-acquisition-of-centrio-leading-us-district-energy-platform-301335780.html
17. ENGIE North America / Ohio State / University of Iowa / CenTrio / Duquesne, University energy public-private partnerships (Ohio State $1.015B upfront + $150M academic, 2017; Iowa $1.165B, 2020; Georgetown; Syracuse $245M + $118M modernization; Duquesne $102M + $50M). https://www.projectfinance.law/publications/2021/august/university-energy-partnerships/
18. Brookfield Infrastructure, Sale of North American District Energy Business (2021, ~$4.1B aggregate EV, Canadian + U.S.). https://bip.brookfield.com/press-releases
19. District Energy St. Paul, 2025 Annual Report and Heating/Cooling Rates (FY2025 $39.7M operating revenue; $6.44/kW/mo + $28.73/MWh heating; $34.19/ton/mo + $0.093/ton-hour cooling). https://www.districtenergy.com/
20. Austin Energy, FY2025 Annual Report (4 district energy/cooling areas; >28M ft²; 73 customers; 64,000+ tons cooling; 169 MW peak shift). https://austinenergy.com/about/reports-and-data
21. Architect of the Capitol, Capitol Power Plant (federal steam and chilled water to the Capitol and 22 facilities; stopped generating electricity in 1951). https://www.aoc.gov/explore-capitol-campus/buildings-grounds/capitol-power-plant
22. Internal Revenue Service / Treasury, Inflation Reduction Act — Section 48 / 48E Investment Tax Credit and Section 45Y Production Tax Credit (CHP, geothermal, thermal storage; 6%–30% ITC; elective/direct pay for tax-exempt owners; PTC rewards electricity, not thermal). https://www.irs.gov/credits-deductions/elective-pay-and-transferability
23. Federal Energy Regulatory Commission, PURPA Qualifying Facilities (cogeneration QF; Form 556). https://www.ferc.gov/qf
24. U.S. Environmental Protection Agency, Title V permits / New Source Review / Boiler MACT (40 CFR Part 63 Subpart DDDDD) / Greenhouse Gas Reporting Program (25,000 mt CO₂e threshold). https://www.epa.gov/nsr
25. New York City, Local Law 97 (Climate Mobilization Act, 2019) — building carbon caps with district-steam emission factors. https://www.nyc.gov/site/sustainablebuildings/ll97/local-law-97.page
26. City of Boston, Building Emissions Reduction and Disclosure Ordinance (BERDO) — $234/metric-ton alternative compliance payment. https://www.boston.gov/departments/environment/berdo
27. Building Decarbonization Coalition / NY Department of Public Service / Eversource, Thermal Energy Network legislation and pilots (NY UTENJA 2022; ~12 pilots ~$880M; WA/MD/VT laws 2024; Eversource Framingham networked geothermal). https://buildingdecarb.org/
28. U.S. Environmental Protection Agency, Methods for Calculating CHP Efficiency (typical 60%–80% total-system efficiency). https://www.epa.gov/chp/methods-calculating-chp-efficiency
29. Consolidated Edison, Historical stock price and dividend history ($112.37 close July 17, 2026; 2025 EPS $5.66; $3.55 annual dividend; ≈19.9× P/E; 3.16% yield — calculated). https://investor.conedison.com/stock-information
30. U.S. Nuclear Regulatory Commission, What NRC Regulates (commercial nuclear reactors; not applicable to NAICS 221330; nuclear generation is NAICS 221113). https://www.nrc.gov/reactors/operating
31. Mordor Intelligence / MarketsandMarkets, District Heating Market size and outlook (global ~$53B; ~1.5% CAGR; data-center waste-heat reuse) — broader global-scope context, not the U.S. figure. https://www.mordorintelligence.com/industry-reports/district-heating-market
32. Missouri Public Service Commission, Order approving Vicinity Energy Kansas City tariff (Production Adjustment Cost Clause fuel reconciliation, 2025). https://efis.psc.mo.gov/