# AC transmission: Value chain

Who makes the transformers, who owns the wires, who pays

Source page: https://www.materialinsights.org/energy/e_hvac/valuechain/

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

Equipment makers supply transformers, switchgear and conductors; developers and transmission owners build and own the lines; system operators run them; regulators approve plans and set the allowed revenue that customers pay.

#### The chain
 Transformer and substation equipment makers Transmission owners and developers System operators and planners Regulators End users

| Stage | What happens | Leading companies |
|---|---|---|
| **Transformer and substation equipment makers** | Make power transformers, reactors, switchgear and grid-control systems. Hitachi Energy describes itself as the world's largest transformer maker; Hyosung supplies nearly half of US 765 kV transformers; brokers name China XD Electric and TBEA among China's leading UHV equipment suppliers. | Hitachi Energy (Switzerland/Japan) Siemens Energy (Germany) Hyosung Heavy Industries (South Korea) China XD Electric (China) TBEA (China)^[21](https://hitachienergy.com/news-and-events/press-releases/2025/03/hitachi-energy-invests-additional-250-million-usd-to-address-global-transformer-shortage)^[22](https://www.tdworld.com/21282724)^[23](https://www.koreajoongangdaily.com/business/hyosung-heavy-industries-secures-540-million-ultra-high-voltage-transformer-contract-in-us/12240917)^[24](https://www.webull.com/news/15256874082313216) |
| **Transmission owners and developers** | Finance, build and own lines, earning a regulated return | State Grid Corporation of China (China) Ameren Transmission Company of Illinois (United States) GridLiance Heartland, part of NextEra Energy Transmission (United States) Dairyland Power Cooperative (United States)^[8](https://www.publicpower.org/node/31550)^[10](https://www.enerdata.net/publications/daily-energy-news/china-plans-15-new-ultra-high-voltage-transmission-lines-2030.html) |
| **System operators and planners** | Balance supply and demand second by second, plan the network and run wholesale markets | ERCOT (United States) MISO (United States) Red Eléctrica (Spain) RTE (France)^[5](https://www.ercot.com/files/docs/2023/06/27/2_ERCOT%20Discussion%20of%20EHV%20and%20HVDC_MISO_Tackett_20230626.pdf)^[6](https://www.ercot.com/files/docs/2025/01/27/2024-regional-transmission-plan-rtp-345-kv-plan-and-texas-765-kv-strategic-transmission-expans.pdf)^[25](https://www.ree.es/en/activities/unique-projects/submarine-interconnection-with-france) |
| **Regulators** | Approve plans and costs, set planning rules and decide who pays | FERC (United States) Public Utility Commission of Texas (United States)^[11](https://www.publicpower.org/periodical/article/ferc-addresses-long-term-planning-regional-transmission-cost-allocation)^[15](https://interchange.puc.texas.gov/Documents/55249_7_1414447.PDF) |
| **End users** | Households, businesses and distribution companies, who pay transmission charges in their bills | ^[4](https://www.eia.gov/tools/faqs/faq.php?id=105) |

Transmission is a natural monopoly: parallel competing lines make no sense, so owners are regulated and earn a set return on what they invest. Global transmission investment grew 10% to USD 140 billion in 2023. Labour is tight too: about 8 million people work on grids worldwide, and the IEA says at least 1.5 million more are needed by 2030.

#### Sources

1. [How much electricity is lost in electricity transmission and distribution in the United States? (FAQ)](https://www.eia.gov/tools/faqs/faq.php?id=105) US EIA, 2023
2. [Discussion of EHV and HVDC (M. Tackett, MISO, presentation to ERCOT)](https://www.ercot.com/files/docs/2023/06/27/2_ERCOT%20Discussion%20of%20EHV%20and%20HVDC_MISO_Tackett_20230626.pdf) MISO / ERCOT, 2023
3. [2024 Regional Transmission Plan: 345 kV Plan and Texas 765 kV Strategic Transmission Expansion Plan](https://www.ercot.com/files/docs/2025/01/27/2024-regional-transmission-plan-rtp-345-kv-plan-and-texas-765-kv-strategic-transmission-expans.pdf) ERCOT, 2025
4. [MISO selects Ameren, GridLiance and Dairyland consortium for EASL 765 kV project (reporting MISO's cost estimate)](https://www.publicpower.org/node/31550) American Public Power Association, 2026
5. [China plans 15 new ultra-high-voltage transmission lines by 2030](https://www.enerdata.net/publications/daily-energy-news/china-plans-15-new-ultra-high-voltage-transmission-lines-2030.html) Enerdata, 2026
6. [FERC addresses long-term planning, regional transmission cost allocation](https://www.publicpower.org/periodical/article/ferc-addresses-long-term-planning-regional-transmission-cost-allocation) American Public Power Association, 2024
7. [AEP Companies' comments about extra high voltage transmission lines to the ERCOT region (Project 55249, citing MISO 2024 Transmission Cost Estimation Guide)](https://interchange.puc.texas.gov/Documents/55249_7_1414447.PDF) Public Utility Commission of Texas, 2024
8. [Hitachi Energy invests additional USD 250 million to address global transformer shortage](https://hitachienergy.com/news-and-events/press-releases/2025/03/hitachi-energy-invests-additional-250-million-usd-to-address-global-transformer-shortage) Hitachi Energy, 2025
9. [Transformer shortage: Siemens Energy to expand manufacturing in Charlotte, North Carolina](https://www.tdworld.com/21282724) T&D World, 2024
10. [Hyosung Heavy Industries secures USD 540 million ultra-high-voltage transformer contract in US](https://www.koreajoongangdaily.com/business/hyosung-heavy-industries-secures-540-million-ultra-high-voltage-transformer-contract-in-us/12240917) Korea JoongAng Daily, 2026
11. [CITIC Securities: focus on power equipment leaders released by UHV demand](https://www.webull.com/news/15256874082313216) CITIC Securities via Webull News, 2026
12. [Spain-France submarine interconnection](https://www.ree.es/en/activities/unique-projects/submarine-interconnection-with-france) Red Eléctrica, 2025

## Other sections

- [Summary](https://www.materialinsights.org/energy/e_hvac/index.md)
- [Overview](https://www.materialinsights.org/energy/e_hvac/overview/index.md)
- [Correlation](https://www.materialinsights.org/energy/e_hvac/correlation/index.md)
- [How it works](https://www.materialinsights.org/energy/e_hvac/explain/index.md)
- [Efficiency and losses](https://www.materialinsights.org/energy/e_hvac/efficiency/index.md)
- [Technology advances](https://www.materialinsights.org/energy/e_hvac/advances/index.md)
- [Geopolitics and regulation](https://www.materialinsights.org/energy/e_hvac/geopolitics/index.md)
- [Unit economics](https://www.materialinsights.org/energy/e_hvac/economics/index.md)
- [Impact on the biosphere](https://www.materialinsights.org/energy/e_hvac/biosphere/index.md)
- [Relationships](https://www.materialinsights.org/energy/e_hvac/links/index.md)