Generators and alternators: Value chain

Who builds the giant machines that feed the grid

What this tab covers Who does what, from equipment makers to builders, owners, operators, traders and users, with the leading companies at each step.

Large generators are made by the same groups that make turbines, and are usually sold as part of the turbine-generator set. Smaller alternators are built into gensets by engine packagers.

The chain

Materials and components Large turbo-generator makers Hydro and smaller generator makers Genset alternator packagers Owners and service

Stage	What happens	Leading companies
Materials and components	Copper conductor, laminated electrical steel for the core, large steel rotor forgings, insulation systems and, for wind machines, rare-earth permanent magnets.	¹
Large turbo-generator makers	Design and build generators for steam, gas and nuclear turbines, usually sold inside the turbine-generator package. In 2025 Dongfang Electric produced about 58 GW of steam turbine generators and Harbin Electric about 28 GW.	GE Vernova (United States) Siemens Energy (Germany) Arabelle Solutions (France) Toshiba (Japan) Dongfang Electric (China) Harbin Electric (China) Shanghai Electric (China) Bharat Heavy Electricals (India)¹²³⁴⁵⁸⁹¹¹¹⁰
Hydro and smaller generator makers	Supply generators for hydro, industrial turbines and wind. Dongfang and Harbin each made about 8 GW of hydro generating units in 2025.	Dongfang Electric (China) Harbin Electric (China) Siemens Energy (Germany, wind generators up to 10 MW)³⁸⁹
Genset alternator packagers	Pair engines with alternators for backup and prime power.	Caterpillar (United States) Cummins (United States, also makes alternators) Generac (United States) Rehlko, formerly Kohler Energy (United States) Rolls-Royce Power Systems, mtu (Germany) Volvo Penta (Sweden)⁶¹²¹³¹⁴
Owners and service	Plant owners run generators for decades; makers rewind stators, re-wedge rotors and upgrade insulation during outages. GE Vernova reports an installed fleet of over 6,700 air-cooled units.	GE Vernova (United States) Siemens Energy (Germany) Arabelle Solutions (France)¹²³

Sources

GIGATOP generators Arabelle Solutions, 2025
Air-cooled generators (GEN-A) GE Vernova, 2025
Generators for power generation (product overview and references) Siemens Energy, 2025
Harbin Electric wins bids for two 2 GW coal-fired power projects in China Enerdata, 2024
GE HA Turbine Snags Another World Record for CCGT Efficiency POWER Magazine, 2018
Engine Power Plants Surge as Data Centers Drive Unprecedented Demand POWER Magazine, 2026
Dongfang Electric Corporation Limited: Annual results announcement for the year 2025 Dongfang Electric (HKEX filing), 2026
Harbin Electric Company Limited: Annual results announcement for the year ended 31 December 2025 Harbin Electric (HKEX filing), 2026
BHEL: order for 1x800 MW Anuppur thermal power project (stock exchange disclosure) Bharat Heavy Electricals Ltd (NSE filing), 2025
Shanghai Electric Power Generation Group (company profile) Shanghai Electric, 2025
Generac reports fourth quarter and full-year 2025 results Generac Holdings, 2026
Kohler Energy changes name to Rehlko Equipment World, 2024
Cummins Inc. Form 10-K for fiscal year 2025 Cummins / US SEC, 2026