What KMW does

KMW (Kraftwerke Mainz-Wiesbaden AG) is a municipal utility company headquartered in Mainz, Germany, supplying electricity, district heating, natural gas, and waste incineration services to the Greater Mainz-Wiesbaden metropolitan area since 1930. Its core operations span a diversified generation portfolio including a 100 MW electrical / 90 MW thermal Blockheizkraftwerk (combined heat and power plant commissioned 2021), a gas-and-steam turbine plant, a waste-to-energy plant, wind parks, and a 9.53 million kWh/year solar park at Kirchheimbolanden. The company is also building a 60 MWh / 22 MW battery storage system and a 54 MW hydrogen-ready peaking gas motor plant for commissioning in 2027, alongside a planned Zukunftskraftwerk (~250 MW) and industrial Großwärmepumpe.

Through the 2023 50/50 joint venture Green Mountain KMW Data Center GmbH with the Norwegian operator Green Mountain (an Azrieli Group company), KMW is expanding into sustainable data center colocation via the Green Rocks campus on its Ingelheimer Aue industrial site, targeting up to 54 MW IT load across three buildings with Rhine water cooling delivering PUE below 1.3 and waste-heat recovery feeding Mainz's district heating network. The integrated energy hub combines power generation, battery storage, gas network operation, hydrogen-ready infrastructure, data center operations, and district heating — drawing synergies from co-located assets that competing operators cannot easily replicate. Revenue mechanics are multi-stream: regulated electricity and district heating tariff supply to municipalities and regional customers, capacity payments and usage-based revenues from German balancing power markets, subscription-like municipal waste incineration services, and emerging enterprise colocation revenue. Ownership is split 50/50 between Mainzer Stadtwerke AG and ESWE Versorgungs AG (Wiesbaden), with supervisory board leadership from the two cities' mayors confirming its character as a kommunaler Stadtwerke utility rather than a private or publicly listed entity.

Name

KMW

Legal name

Kraftwerke Mainz-Wiesbaden AG

Website

https://kmw-ag.de

Company type

Private

Founded year

1930

Operating status

Operating

Headcount range

251–500 employees

Short description

KMW (Kraftwerke Mainz-Wiesbaden AG) is a Mainz-based municipal utility supplying electricity, district heating, natural gas, and waste-to-energy services to the Greater Mainz-Wiesbaden region, with growing operations in hydrogen-ready power generation, battery storage, and sustainable data center colocation via its Green Mountain joint venture.

Ownership category

akta.pro rank

Product category

Municipal Energy and District Heating Utility

NAICS

Steam and Air-Conditioning Supply (221330), Steam and Air-Conditioning Supply (22133), Pipeline Transportation of Natural Gas (486210)

SIC

Cogeneration Services & Small Power Producers (4991), Natural Gas Transmisison & Distribution (4923), Engines & Turbines (3510), Sanitary Services (4950)

akta.pro primary industry

District Energy & Community CHP (District Heating/Cooling Networks) (EUACAKAH)

akta.pro secondary industries

Natural Gas CHP (Industrial & Utility-Scale) (EUACAKAA), Waste-to-Energy CHP (Municipal/Industrial Waste Incineration) (EUACAKAC), Hydrogen CHP (Fuel Cell & H2-Ready Turbines) (EUACAKAF), District Energy & CHP-Based Microgrids (Thermal Networks + Power) (EUACALAL), Onsite Low-Carbon Heat & CHP (Electrified CHP, Fuel Cells, Renewable CHP) (EUABAJAI)

Keywords

• Municipal power generation
• District heating supply
• Waste-to-energy operations
• Energy data center colocation
• Renewable energy infrastructure

Headquarters

HQ city

Mainz

HQ country

Germany

HQ region

Europe

Offices2 records

Markets served

GTM type

B2B

Offering type

Services

Cost components

Personnel, Operations, Infrastructure, Supply Chain, Technology or R&D, Marketing or Sales

Revenue model

1. Electricity Generation and Sales: KMW generates electricity through diverse power plants (gas motors, combined cycle, waste-to-energy, wind, solar) and sells to the German grid and regional customers. The company participates in balancing power markets and provides grid stabilization services.
2. District Heating Sales: Combined heat and power generation provides district heating to Mainz city, supplying approximately 20% of Mainz's building heating needs, including large customers like universities and sports stadiums.
3. Waste Incineration Services: Municipal waste-to-energy plant processes waste to generate electricity and district heating, providing essential public waste management services.
4. Gas Network Operations: KMW operates natural gas distribution network serving industrial and commercial customers in the region.
5. Data Center Services: Joint venture with Green Mountain operates the Green Rocks data center, providing co-location services with up to 54 MW capacity to international enterprise customers.
6. Balancing and Reserve Power Markets: Flexible generation assets participate in German balancing power and reserve energy markets, providing grid stabilization services and earning capacity payments.

Go-to-market motion1 record

Distribution channels4 records

Marketing channels7 records

Core offering

KMW is a municipal energy utility that generates electricity and district heating through a diversified portfolio of gas motor combined heat and power (CHP) plants, combined-cycle gas turbines, a waste-to-energy incineration plant, wind parks, and solar parks. It operates a natural gas distribution network, provides grid stabilization and balancing power services, supplies district heating to roughly 20% of Mainz's building heating needs, and (via a 50/50 JV with Green Mountain) is co-developing the 54 MW Green Rocks sustainable data center on the Ingelheimer Aue site. The company is investing in hydrogen-ready generation, battery storage, and CO2-to-methanol conversion to support the energy transition.

Differentiator

Problem solved

Functional benefit

Brands

• Green Rocks: A sustainable data center brand developed by the joint venture between KMW and Green Mountain, featuring renewable energy power supply, efficient cooling via Rhine water, and waste heat utilization for district heating.

Products and services

• Green Rocks Data Center Colocation Sustainable colocation data center service on Ingelheimer Aue, developed and operated via the 50/50 KMW-Green Mountain JV (Green Mountain KMW Data Center GmbH). Up to 54 MW IT load across three buildings on a 25,000 sqm site, powered by renewable KMW energy with Rhine River water cooling (PUE under 1.3), aviation-grade backup power from the planned 54 MW motor power plant, and waste-heat recovery into Mainz district heating. Targeted at international enterprise data center customers requiring high-availability infrastructure for AI and cloud workloads.
• District Heating Supply (Fernwärme) District heating service supplied to the city of Mainz from the Blockheizkraftwerk (BHKW) on Ingelheimer Aue, covering approximately 20% of Mainz's building heating needs. Customers include large institutional users such as universities and the MEWA Arena stadium, plus up to 20,000 additional households once data-center waste-heat recovery via large-scale heat pumps comes online.
• Combined Heat and Power Generation (BHKW) Blockheizkraftwerk (BHKW) combined heat and power generation service on Ingelheimer Aue, delivering 100 MW electrical and 90 MW thermal capacity with a heat-utilization rate exceeding 85%. Electricity feeds the German grid and balancing power markets, while heat is supplied via the Fernwärme network to Mainz.
• Battery Storage and Grid Stabilization Service Grid-scale battery energy storage service (60 MWh / 22 MW) on Ingelheimer Aue, supplied by INTILION GmbH, providing flexibility services, renewable integration, and grid stabilization in the German balancing power markets. Equivalent to daily electricity needs of about 2,700 households.
• Motor Power Plant Peaking and Backup Service (54 MW, H2-Ready) Peaking power and backup supply service from a planned 54-MW motor power plant on Ingelheimer Aue, using twelve Jenbacher gas engines from INNIO Group. Hydrogen-ready design, fast-start (2.5-minute) capability, and primary function of stabilizing the grid and backing up the Green Rocks data center.
• Waste-to-Energy / Municipal Waste Incineration Service Municipal waste-to-energy (Müllheizkraftwerk) service processing municipal waste to generate electricity and district heating, providing essential public waste management for regional municipalities under direct contracts. By-product CO2 is captured for the CO2-to-methanol conversion system.
• Natural Gas Distribution Network Service Operation of a regional natural gas distribution network serving industrial and commercial customers in the Mainz-Wiesbaden region. TSM-reviewed for gas-supply technical safety management (DVGW).
• Solarpark Kirchheimbolanden (Solar Power Generation) Grid-scale solar power generation service from the Solarpark Kirchheimbolanden, operated by KMW subsidiary ALTUS renewables GmbH. 14,094 PV modules generate about 9.53 million kWh annually, saving approximately 7,174 tonnes of CO2 per year.
• Wind Park Electricity Generation Electricity generation from KMW's wind parks equipped with demand-controlled night marking (BNK) systems that activate aviation warning lights only when low-flying aircraft are detected. Power feeds the German grid alongside other KMW generation assets.
• Balancing and Reserve Power Market Service Participation by KMW's flexible generation assets in German balancing power and reserve energy markets, providing grid stabilization services to transmission system operators such as Amprion and earning capacity payments.
• CO2-to-Methanol Conversion and Hydrogen Supply Service CO2 captured from waste-to-energy exhaust is combined with hydrogen from a 25 MW electrolyzer to produce approximately 16,000 tonnes of methanol per year. A 5 km dedicated hydrogen pipeline connects the Ingelheimer Aue industrial area to Mainz main train station to supply industrial customers and public transport.

Quantifiable outcome

• Up to 95% lower NOx emissions compared to traditional diesel generators for peaking power plant
• +7 more outcomes

Named customers1 record

Segments4 records

Ideal customer profiles4 records

Technology focussed No

API detail

Has API

No

API docs

API detail

Core technology

AI maturity

App detail

Integration1 record

Feature7 records

Partnerships

Eleven partnerships are on record, tiered core, supporting and strategic.

• INNIO GroupcoreTechnology or Integration · 7 November 2025Contract signed for 54-MW peaking power plant featuring twelve Jenbacher modular energy systems for grid stabilization. INNIO provides gas engine technology with up to 95% lower NOx emissions than diesel generators and hydrogen-ready capability. Scheduled for commissioning by end of 2027.
• Karrié Bau GmbHsupportingImplementation/ SI/ Consulting Partner · 1 May 2025Regional Mainz-based construction company contracted as general contractor for KMW's new workshop and office building. Note: Insolvency proceedings announced October 2025, construction currently suspended.
• Rh2ein-Main Connect ConsortiumcoreStrategic or Co-development Partner · 20 March 2024Regional hydrogen network consortium including ENTEGA AG, Mainova AG, ESWE Versorgungs AG, Open Grid Europe GmbH (OGE), e-netz Südhessen AG, and NRM Netzdienste Rhein-Main GmbH developing a 300 km hydrogen distribution network for the Frankfurt/Rhein-Main region from 2028.
• INTILION GmbH (HOPPECKE Group)coreTechnology or Integration · 1 January 2024INTILION provides modular battery storage systems for the 60 MWh / 22 MW battery storage project on Ingelheimer Aue. INTILION is a leading provider of modular battery storage solutions and part of the owner-managed HOPPECKE Group based in Paderborn.
• ESWE BioEnergie GmbHsupportingGTM or Marketing Partner · 1 January 2024Subsidiary of ESWE Versorgungs AG collaborated with KMW on joint procurement of 12 battery containers for the storage project, demonstrating efficient cross-company cooperation in technology procurement.
• Green Mountain (Azrieli Group)coreStrategic or Co-development Partner · 30 March 2023Joint venture Green Mountain KMW Data Center GmbH (50/50 ownership) developing and operating the Green Rocks sustainable data center on Ingelheimer Aue. Green Mountain provides data center expertise and customer acquisition while KMW provides integrated energy infrastructure including power supply and backup generation. Azrieli Group is the parent company of Green Mountain following 2021 acquisition.
• GP Con (Groß & Partner)strategicImplementation/ SI/ Consulting Partner · 1 January 2023GP Con, a subsidiary of Groß & Partner from Frankfurt, serves as the general contractor for constructing the Green Rocks data center buildings. Construction began September 2023 with first building scheduled for Q1 2026 completion.
• TTSP HWP Planungsgesellschaft mbHsupportingImplementation/ SI/ Consulting Partner · 1 January 2023Frankfurt-based specialized data center general planner providing technical planning services for the Green Rocks facility. Supported by GePlan Ingenieure GmbH & Co. KG from Hennef.
• Kölling ArchitektensupportingImplementation/ SI/ Consulting Partner · 1 January 2023Architecture firm from Bad Vilbel selected through facade competition to design the aesthetic exterior of the Green Rocks data center buildings.
• Mainzer Stadtwerke AGcoreStrategic or Co-development Partner · 18 March 2021Joint hydrogen infrastructure development including 25 MW electrolyzer for CO2-to-methanol conversion and shared hydrogen pipeline network. Both KMW and Mainzer Stadtwerke are pursuing IPCEI funding for hydrogen technologies.
• Wärtsilä Energy SolutionsstrategicTechnology or Integration · 1 January 2020Wärtsilä was the technology partner for the 100 MW gas motor power plant completed in 2020 on Ingelheimer Aue. The Finnish company provided ten gas-fired engines for the facility.

Scale indicators9 records

Recent moves6 records

Expansion highlights6 records

Direct peers

• Mainova AG: Frankfurt-based municipal energy utility that is a core partner alongside KMW in the Rh2ein-Main Connect hydrogen network consortium. Directly comparable as a regional German Stadtwerke with district heating, gas distribution, and hydrogen-transition strategy in the same Rhein-Main market.
• ESWE Versorgungs AG: Wiesbaden municipal utility and 50% owner of KMW. Operates the same regional market with overlapping electricity, gas, and district-heating infrastructure; comparable municipal-utility governance and hydrogen ambitions.
• Mainzer Stadtwerke AG: Mainz municipal utility and 50% owner of KMW. Joint hydrogen infrastructure developer with KMW (electrolyzer and pipeline); comparable in scale, customer base, and decarbonization roadmap in the same city.
• ENTEGA AG: Darmstadt-based regional energy utility and Rh2ein-Main Connect consortium partner with KMW. Operates electricity, gas, district heating, and renewables with a comparable municipal-ownership profile and hydrogen transition strategy in the Rhein-Main region.
• Green Mountain: Norwegian data center operator (Azrieli Group) and KMW's 50/50 JV partner in Green Mountain KMW Data Center GmbH. Directly comparable as a sustainable colocation provider using hydropower and now co-developing Rhine-Main capacity with KMW.

Broad incumbents

• RheinEnergie AG: Cologne municipal utility of significantly larger scale with a comparable mixed portfolio of CHP, district heating, gas distribution, and renewable energy. Broadly relevant as a larger German Stadtwerke peer executing a similar energy-transition capex program.
• Stadtwerke München (SWM): Largest German municipal utility, operating CHP, district heating, renewable energy, and now data center infrastructure through its investment in Mainframe. Comparable end-markets (multi-utility, district heating, hydrogen, data centers) at a much larger scale, serving as a strategic benchmark for KMW's integrated energy-hub concept.
• Leipziger Stadtwerke: Major German municipal utility operating CHP, district heating, gas networks, and renewable generation. Comparable as a multi-vector Stadtwerke with active decarbonization and hydrogen pilots in eastern Germany.
• N-ERGIE Aktiengesellschaft: Nürnberg-based regional municipal utility operating electricity, gas, district heating, and renewable assets. Comparable mid-sized Stadtwerke with similar multi-utility structure and regulated municipal ownership.

Regional players

• NRM Netzdienste Rhein-Main GmbH: Frankfurt-based gas distribution network operator that is part of the Rh2ein-Main Connect hydrogen consortium with KMW. Comparable as a regional gas-network infrastructure player pivoting to hydrogen, though smaller in scope than KMW's integrated portfolio.

Market position

Strengths5 records

Weaknesses5 records

Competitive moat7 records

Key risks6 records

Key highlights6 records

Customer concentration

• LinkedInde.linkedin.com/company/kraftwerke-mainz-wiesbaden-ag

Revenue estimate

Valuation estimate

Number of profiles

Profiles4 records

Subsidiaries4 records

Funding overview

Funding rounds

Investors

Funding detail is available on the Subscription and Enterprise plan.Contact sales →

M&A

Investments

M&A and investment is available on the Subscription and Enterprise plan.Contact sales →

Frequently asked questions about KMW