Tesla Solar (SolarCity) Supply Chain in 2026: Who Actually Makes the Panels?

Tesla assembles its TSP-415 and TSP-420 solar panels at Gigafactory New York in Buffalo — but it does not make the solar cells inside them, and it has not disclosed who does. That single gap defines the entire Tesla solar supply chain in 2026, and it has a direct financial consequence for buyers using lease financing. Here is the full chain, from the SolarCity acquisition to the 100 GW Texas plan.

Who Makes Tesla Solar Panels in 2026?

Tesla’s TSP-420 datasheet states the modules are "assembled in Buffalo, New York" — wording that points to cells being produced by someone outside the United States, with Tesla performing module assembly at Gigafactory New York (Electrek on the TSP-420 launch).

This is still a meaningful change. For several years Tesla white-labelled panels from third-party manufacturers including Q Cells. The TSP series is a proprietary Tesla design, with 18 independent power zones per module — roughly three times the zoning of a conventional panel — derived from the cascading cell technology developed for Solar Roof (pv magazine USA).

The FEOC gap most reviews skip

Tesla has not publicly claimed Foreign Entity of Concern compliance for the TSP-420, and cell sourcing remains undisclosed. FEOC compliance requires that cells and critical minerals are not sourced from entities connected to China, Russia, Iran or North Korea.

The practical consequence: under Sections 48/48E, a third-party system owner in a lease arrangement can claim the domestic-content bonus only with FEOC-compliant panels. Without that confirmation, homeowners using certain lease financing paths lose access to a meaningful federal incentive (installer analysis of TSP-420 FEOC status).

From SolarCity to 2026: How This Supply Chain Got Here

The Solar Roof Retreat

Solar Roof, unveiled in October 2016 as the cornerstone of Tesla’s energy vision, never reached meaningful volume. Tesla did not achieve even small-scale production until 2020, three years behind schedule, and coverage in 2026 describes the product as effectively shelved after missing production targets by a wide margin (analysis of the Solar Roof pivot).

The technical irony is instructive. Solar Roof’s string-inverter architecture handled shading poorly, and its tile format made that worse. The TSP panel replacing it uses an 18-zone layout that directly addresses shading — the flaw the original product never solved.

Tesla Energy’s own framing of the new panel was that "this panel completes the full package of the residential energy ecosystem" — language that quietly reassigns the role Solar Roof was supposed to play (pv magazine interview).

The Brookshire Bet: Real Vertical Integration

At Davos in January 2026, Musk announced that Tesla and SpaceX would each independently build 100 GW per year of US solar manufacturing capacity by 2028, "integrating across the entire supply chain from raw materials" through to finished panels (coverage of the 100 GW plan).

The site is Brookshire, Texas, at Empire West Business Park roughly 35 miles west of Houston, co-located with Tesla’s Megapack Megafactory. Tesla leases Buildings 9 and 10 totalling 1.65 million square feet, with a further 600,000 square feet planned, and the operation is designed to span ingot growth, wafer slicing, cell production and module assembly (Electrek on the Brookshire facility).

The paradox at the heart of the plan

To build American solar independence, Tesla is buying Chinese equipment. CNBC reported negotiations for $2.9 billion of Chinese solar manufacturing tooling, with Suzhou Maxwell Technologies — the world’s largest producer of screen-printing equipment for solar cells — among the leading suppliers, alongside Shenzhen S.C New Energy and Laplace (Electrek on the equipment deal).

China’s Ministry of Commerce approved Maxwell’s export of HJT turnkey lines and screen-printing equipment to Tesla and SpaceX on March 31, 2026 — the milestone that made the plan credible rather than aspirational.

Three Dependencies Tesla Cannot Escape Yet

• The cell itself. Until Brookshire produces cells at volume, every Tesla panel contains someone else’s cell. That is the difference between a manufacturer and an assembler, and it is why the FEOC question stays unanswered.
• The tooling. The equipment required to make cells at scale is overwhelmingly Chinese. Beijing has made export controls a stated priority, and approval is granted case by case — leverage that persists after the equipment ships.
• The policy window. Solar manufacturing equipment was excluded from Section 301 tariffs in 2024 at the request of US panel makers, and that exemption runs through November 2026. Equipment landing after that window may face very different economics.

The Policy Shock Nobody Priced In

The One Big Beautiful Bill Act ended federal solar tax credit funding for residential systems after December 31, 2025. Conventional wisdom said that would crater demand.

It did not, at least initially. Tesla reported a surge in US residential solar demand and launched a solar lease product designed to make adoption affordable without the upfront credit, while expanding its solar team for the first time in five years (Tesla energy commentary on the demand surge).

That is the strategically interesting move: when the purchase incentive disappeared, Tesla shifted the ownership model rather than the price. Leases and PPAs move the tax benefit to the system owner — which is precisely why the FEOC question above became financially material.

Why Storage, Not Solar, Pays the Bills

Context that reframes everything above: Tesla deployed a record 46.7 GWh of energy storage in 2025, up 48% year over year, generating $12.8 billion in revenue at a 29.8% gross margin — roughly double what Tesla earns selling cars. Storage now accounts for around 13% of total revenue and 23% of gross profit (Electrek on Tesla energy economics).

Solar is not the profit centre. It is the demand generator that makes Powerwall and Megapack more valuable, and increasingly the electricity source for Tesla’s own AI compute build-out. Judge the solar supply chain by what it enables, not by its standalone margin.

Checklist: What to Verify Before Buying Tesla Solar in 2026

• Ask for the cell country of origin in writing. "Assembled in Buffalo" describes module assembly only.
• Confirm FEOC status and whether the domestic-content bonus applies to your specific financing structure.
• Compare efficiency honestly. The TSP-420 sits at 20.5%, below leading REC, Qcells and Maxeon modules — the trade is shade tolerance and aesthetics, not peak output.
• Check the warranty term. Tesla moved from a 10-year product warranty on older series to 25 years on the TSP — make sure your quote is the new series.
• If you have an existing Solar Roof, get service commitments documented. The product line has been deprioritized.
• Price the ecosystem, not the panel. The 18-zone design is tuned for the Tesla string inverter; mixing brands erodes the main advantage.
• Verify installer status. Tesla now sells substantially through third-party certified installers rather than internal crews.

FAQ

The Bottom Line

Tesla’s solar supply chain in 2026 is one step deep and three steps short. Module assembly is real and domestic. Cells, wafers and ingots are not — and until Brookshire runs, Tesla is a solar assembler with a strong brand, not a solar manufacturer.

The Texas plan is the first genuinely credible attempt to close that gap in a decade of trying, and it depends on Chinese equipment, a tariff exemption expiring in November 2026, and an execution timeline that would be unprecedented in the industry.

For buyers, the actionable takeaway is smaller and sharper: get cell origin and FEOC status in writing before you sign anything, because the label on the datasheet does not tell you what you are actually buying.

Sources: Electrek, pv magazine USA, Teslarati, Carbon Credits, energiesmedia, NuWatt Energy, EnergySage. Cell sourcing and supplier relationships are reported by third parties and not confirmed by Tesla. Last fact-check: August 5, 2026.