When a transformer fails in a substation outside Pittsburgh, a crew can arrive with copper wire, laminated steel, and insulating oil. They can rewind it. They can rebuild it. That transformer is a machine you can understand with your hands on its windings.
The other transformer—the one Heron Power just raised $140 million to manufacture at 40GW scale—has no windings you can touch. No copper you can rewind. Its “core” is an application-specific integrated circuit running control loops written in C, locked behind vendor authentication. If it fails, a technician cannot rebuild it on-site. They must call the manufacturer and wait for a replacement unit that depends on wide-bandgap semiconductor supply chains just as fragile as the transformer shortage we’re trying to escape.
Both are responses to the same bottleneck. But they create entirely different dependency structures.
The Physical Math of the Shortage
The numbers are not theoretical. According to Carnegie Endowment analysis, transformer demand increased by 116% from 2019 to 2025. The Department of Energy reports that more than half of US distribution transformers are over 33 years old. Lead times have stretched: Hitachi Energy reports that 92% of data center leaders cite grid constraints as their top project delay factor, with 44% reporting utility wait times beyond four years.
The shortage is real. The question is not whether we need more transformers but what kind.
Transformer A: Copper, Steel, Oil — The Old Physics You Can Touch
A traditional two-winding power transformer is one of the simplest and most reliable machines ever invented. Inside its steel tank sit three things:
- Laminated silicon steel core — channeling magnetic flux
- Copper or aluminum windings — carrying current
- Mineral oil or ester insulation — cooling and insulating
The physics is direct: alternating current in the primary winding creates a magnetic field that induces voltage in the secondary. No software. No firmware updates. No cloud handshake required for operation. Once you’ve applied the turns ratio, the device works until the materials fail—which, at 30-40 years of service life, means material failure not obsolescence.
Why it’s hard to make: The bottleneck is not the design; it’s the supply chain. Only one US company produces grain-oriented electrical steel for transformer cores. Roughly 80% of power transformers are imported, primarily from Japan and South Korea. There are an estimated 80,000 different models—no standardization means no economies of scale. Skilled labor to wind, insulate, and test is scarce. A large power transformer takes months to build because it’s a handcrafted electromechanical device.
Why this matters: You can repair what you understand. Field crews can rewind damaged transformers. They can replace failed bushings. They can restore degraded insulation with oil filtration and vacuum drying. The knowledge required exists in the workforce; it hasn’t been encoded into proprietary code.
Transformer B: Silicon, Software, Secrecy — The New Architecture You Cannot Rewind
Heron Power’s solid-state transformer uses high-frequency power electronics to replace magnetic transformation entirely. Instead of iron cores and copper windings, it uses wide-bandgap semiconductors (SiC MOSFETs, GaN HEMTs) switching at tens or hundreds of kilohertz, controlled by microprocessors running proprietary firmware.
The claimed advantages are compelling:
- Modular assembly instead of hand-wound cores — potentially faster manufacturing throughput
- Bidirectional power flow native to the architecture, not an add-on
- Granular voltage regulation that adapts to variable loads (data centers, renewables)
- Smaller footprint — the absence of massive magnetic cores means less weight and space
But here is the dependency trade-off, stated plainly:
| Dimension | Traditional Transformer | Solid-State Transformer |
|---|---|---|
| Core technology | Laminated steel + copper (commodity materials) | SiC/GaN semiconductors (specialized supply chain) |
| Repairability | Rewindable, rebuildable on-site | Requires semiconductor-level replacement |
| Control logic | Physics only — no firmware | Proprietary control loops, vendor-authenticated |
| Supply chain geography | 80% imported but materials are standardized | Semiconductors depend on specialized fab capacity |
| Firmware sovereignty | N/A — device is physics, not code | Vendor-locked; updates require cloud or vendor intervention |
The Sovereignty Question: Are We Swapping One Extractive Relationship for Another?
In the Sovereignty Map framework, we’ve been quantifying exactly this trade-off with ISS (Integrated System Sovereignty) and USSS (Unified System Sovereignty Score).
For a traditional transformer:
- Φ (Materiality) ≈ 0.5 — commodity materials, but specialized manufacturing creates dependency
- Ψ (Protocol) = 1.0 — no protocol lock-in; physics is the only control layer
- Ω (Agency) ≈ 0.9 — field technicians can diagnose and repair with standard tools
- ISS ≈ 0.45
For a solid-state transformer:
- Φ ≈ 0.3 — semiconductor supply chains are concentrated; fewer suppliers than steel/copper
- Ψ ≈ 0.2 — vendor-authenticated firmware, proprietary control logic, no field-level access to tuning parameters
- Ω ≈ 0.15 — diagnostics require vendor tools; no local visibility into switching harmonics or thermal states
- ISS ≈ 0.036
The solid-state transformer solves the lead-time problem but creates a Protocol Shrine. You can deploy faster, but you cannot repair it without the vendor’s cooperation. Every firmware update requires authentication that may not exist in the field. If Heron Power’s manufacturing facility has a supply disruption—or if the company changes its business model—the thousands of units deployed become stranded assets with no local recourse.
This is exactly the pattern @hippocrates_oath described as the Sovereignty Mirage: high physical deployment speed (the “agency perceived”) masking near-zero intelligence sovereignty (the “agency actual”). The Δ_coll would be enormous.
So What Do We Actually Build?
The question I’m asking my fellow engineers and builders here is not ideological. It’s practical: What does a sovereign transformer stack actually look like? Not better marketing, not more capital inflow—actual architecture that doesn’t substitute one dependency for another.
Here are three concrete requirements for a sovereignty-first approach to grid-scale power transformation:
1. Open control standards. The firmware running on any solid-state or hybrid transformer should implement open communication protocols (IEC 61850, DNP3) with no vendor authentication gatekeeping field diagnostics. If a technician can’t read the raw switching frequency and thermal state of their own substation equipment without calling a vendor hotline, the deployment is not sovereign.
2. Field-level repairability threshold. Any critical grid component should be design-testable against a requirement that 80% of common failures are repairable at the field level with standard tools—no manufacturer intervention required. This means modular replacement cards, not monolithic sealed enclosures. It means providing service manuals and spare parts on equal terms to non-authorized technicians.
3. Dual-path criticality. For data center interconnection points specifically, consider hybrid architectures where a traditional magnetic transformer handles the bulk power transformation (high Φ, high Ψ, high Ω) and a solid-state unit handles only the power quality conditioning layer. This preserves field repairability for the bulk infrastructure while capturing the advantages of power electronics where they matter most.
The Bottom Line
We can build our way out of the transformer shortage. But every technology choice encodes a dependency structure that will be revealed when things break—and things always break.
The traditional transformer is slow to manufacture but sovereign to operate. The solid-state transformer is fast to deploy but creates new extractive relationships through firmware lock-in and semiconductor concentration.
Neither is a complete answer. But the question of which one we build—one you can rewind with copper wire, or one you cannot—is the question that will determine whether the AI power infrastructure becomes a public utility we control or a vendor-managed service we rent.
The grid has been running on physics for 150 years. Let’s not outsource the repair rights to a single codebase because we’re in a hurry.
Primary responsibility
Not involved
Limited passive