TL;DR — CBAM officially begins levying in 2026, with the additional cost for aluminum at roughly 3.83% of the aluminum price. That seems low, but for “low-margin, high-turnover” commodity goods it’s a profit killer. Worse still, using default values incurs a punitive 10–30% mark-up, pushing costs to around 6% by 2028. The real damage isn’t in the numbers—it’s that if you can’t produce your own measured data, you can only let your competitor set your price. You can’t escape even if you don’t export to the EU, because the cost embedded in the final product gets pushed back down the supply chain onto every upstream player.

In a meeting with a client who makes aluminum extrusions, the general manager set down his teacup and asked me a question: “We don’t directly export to the EU—does CBAM have anything to do with us?”

I asked him in return: “Who are your customers? And who are their customers?”

He gave a small smile and said nothing more. Because the answer was clear to both of us—his customer is a Taiwanese vehicle component supplier, and that supplier’s customer is a German automaker. That supply chain wound around several times, but in the end it still circled back to Brussels.

This is the scene I’ve encountered most often over the past two years as an SSBTi circular economy partner: many people assume CBAM is something you only have to deal with if you export to the EU. In reality, CBAM isn’t a tariff schedule—it’s a regime that, following orders and contracts, seeps backward into the entire supply chain. It is quietly redefining one thing: what kind of company will still be allowed at the table of international trade in the future.

CBAM Isn’t a Calculation Problem—It’s a Supply Chain Management Problem

Many companies’ first reaction to CBAM is: “How do we fill out the form? Who do we hire to do verification? Which emission factor do we use?” These questions aren’t wrong, but they all remain at the level of “exam format.” What CBAM really tests is something else: whether your supply chain can become a verifiable, traceable, externally auditable system.

Put another way, CBAM is a “carbon ticket” for exporting to the EU. How much carbon tariff you pay depends on two things: the full-chain carbon emissions of your exported products, and whether you can produce EU-recognized evidence proving that this number is true, accurate, and traceable. MRV (monitoring, reporting, verification) isn’t three columns—it’s three institutional systems; it’s not a spreadsheet.

There’s a misconception here: carbon emission data isn’t “the lower the better,” it’s the more accurate and provable, the better.

If you report a beautiful low-emission figure but can’t produce actual records, documents, meter readings, or invoice trails, the EU not only won’t believe your number—it will go ahead and take the actual data from the 10 highest-emission-intensity countries that export to the EU, calculate their average, and use that as your default value. The result: what started as a small shortcut may end up costing you more in CBAM than you’d have paid otherwise.

The recoil is even more brutal: if a company is deemed to have filed false declarations, it may face penalties, and it may also lose its CBAM filing eligibility, affecting future imports. In the future, the first to be eliminated won’t necessarily be high-emission companies, but companies that can’t account for their own emissions. I hope every boss still hesitating over whether to build a carbon inventory system pins this sentence up in their office.

Default Values Aren’t a Shortcut—They’re Someone Else Setting Your Price

At the end of 2025, the EU released a CBAM default-value document running to as many as 2,400 pages. The first reaction of anyone who sees it is usually a sigh of relief: “Great, I don’t have to calculate it myself—I’ll just fill in according to this.”

That thought is precisely the trap.

Default values can save you the trouble of calculation, but they carry two costs you must be aware of. The first is on the surface: default values don’t necessarily match your company’s actual situation, and may even be higher than your real value. By not calculating it yourself, you’re voluntarily accepting a number that works against you.

The second cost is deeper, and it’s the one sentence I most want to leave with this article: the default value is itself a pricing weapon.

Take unwrought aluminum: according to the EU’s published default value for China, it’s 3.0 tCO₂/tonne of product (direct emissions only). Where does this 3.0 come from? Which countries, which years, which process routes does the data cover? The document may run to 2,400 pages, but its disclosure of certain data sources and calculation methods is still not necessarily enough for companies to fully judge its reasonableness.

For companies, the meaning is clear: if you can’t produce your own measured data, you can only accept an emissions level defined by someone else—and the definer’s institutional goals and industry interests may not be on your side.

This is the same structure I analyzed in my earlier piece on California’s SB 253: the real function of such laws isn’t to directly regulate emissions, but to turn carbon data into an institutional object that can be audited, compared, and held accountable. Whoever holds credible data holds the bargaining chips for pricing. Whoever doesn’t is left accepting the price someone else sets.

I call this “carbon data sovereignty.” Long-term reliance on EU default values or foreign background databases like Ecoinvent and GaBi is like measuring your own height with someone else’s ruler. In the short term it looks convenient; in the long term it locks you into a position where someone else has the final say. For Taiwanese industry to go global, it can’t merely be a downstream user of data—it must have its own foundation of local data that it can understand, afford, and account for clearly.

The Aluminum Case: 3.83% Looks Low, but It’s Enough to Strangle Margins

Apply this logic to a concrete number, and aluminum is the clearest example.

📊 Calculating CBAM’s Additional Cost for Aluminum

  • China’s unwrought aluminum default value: 3.0 tCO₂/t (per SSBTi analysis, EU document released end of 2025)
  • EU electrolytic aluminum ETS benchmark: 1.464 tCO₂/t (carrying over the 2021–2025 value, which CBAM adopts)
  • Q1 2026 CBAM price: €75.36/t (announced by the EU on 2026-04-07)
  • 2026 ETS free allocation ratio: 97.5%
  • Corresponding carbon price ≈ (3.0 − 1.464 × 97.5%) × 75.36 ≈ €118.5/t
  • Converted ≈ 947 RMB/tonne
  • International aluminum price (LME) ≈ 24,721 RMB/tonne
  • CBAM additional cost ≈ 3.83% of the aluminum price
  • The ETS free allocation ratio decreases annually from 2026 to 2034, raising CBAM’s corresponding cost year by year

3% to 4% may not look high at first glance. But aluminum is a textbook “low-margin, high-turnover” commodity—prices are transparent, competition is fierce, and companies have no room to “pass it on through price increases.” In the end, they usually just have to swallow it into their margins. On top of that, electricity, alumina, and anode carbon make up over 80% of electrolytic aluminum’s costs—all rigid costs with no room for compression. With 3.83% landing entirely on margins, for some players this could mean turning “razor-thin profits” into “all that work for nothing.”

Worse still, the calculation above hasn’t even factored in the default-value mark-up. The EU applies a punitive coefficient on top of the default value for importers who use default values: +10% in 2026, +20% in 2027, and +30% from 2028 onward. In other words, by 2028, if you’re still using default values to clear the same batch of aluminum, the 3.0 will be treated as 3.9 for carbon-price purposes, driving CBAM costs to over 6% of the aluminum price.

This mark-up design is where CBAM truly bares its teeth—it doesn’t treat all filers equally, but uses differential treatment to force you to calculate it yourself. The burden on companies that can produce measured data falls year by year, while the burden on those who refuse to calculate rises year by year. This widening gap will cut the entire supply chain into two worlds.

There’s another severely underestimated signal here: CBAM is essentially an industry-structure elimination mechanism, not just an additional cost.

Primary aluminum will bear higher CBAM pressure; recycled aluminum, if it meets the relevant qualifying conditions, may gain a significant cost advantage because recycled feedstock emissions are calculated differently. In other words, in the EU market, the price competitiveness of primary versus recycled aluminum has already been thoroughly rewritten by CBAM. The EU is using the blunt blade of carbon cost to slowly rewrite the competitive rules between primary and recycled aluminum.

This is also the observation I most often share with clients during my years of circular economy work with SSBTi: the EU isn’t “encouraging carbon reduction”—it’s “redefining who gets to play in this market.” You think this is an environmental issue; in reality it was always an industry-restructuring issue.

If You Don’t Export to the EU, Why Do You Still Have to Pay for CBAM?

Let’s pull the lens back to that aluminum-extrusion boss’s question at the start.

Although CBAM is only levied on products exported to the EU, supply chains are penetrating. A German automaker hit with CBAM costs will demand that its Taiwanese Tier 1 supplier provide carbon data, disclose emissions, and sign contractual reduction commitments; once the Tier 1 supplier receives these requirements, it passes the same demands down to Tier 2 and Tier 3. With each layer deeper, the requirement keeps getting passed on in a different form—it might be an EcoVadis rating, it might be an ISO 14067 product carbon footprint, it might be a CDP Supply Chain disclosure, it might be ISCC certification.

But behind these different labels, what’s really being demanded is the same thing: can you produce credible, traceable full-chain carbon data?

Many companies internally see these as “separate, independent hassles,” requiring them to hire separate consultants, do separate verifications, and make separate fixes. From the perspective of the SSBTi initiative, you can see another, more fundamental structure: CBAM, SBTi, CDP, ISCC, and EcoVadis are independent of one another, but their inner logic is connected—they all want the same supply chain, the same set of emission factors, the same mass-balance and traceability records. A single underlying data system can often support multiple filing and certification needs.

This observation tells us the reverse: building carbon data isn’t a “cost”—it’s infrastructure investment. Build early and amortize early; build late and you’ll only end up paying a high one-off price on every new order contract.

The Four-Step Supply Chain Method: Procurement Can Launch It Today

So how do you actually begin? A method promoted by SSBTi can be organized into four steps—and the key is that these four steps don’t require carbon experts to be in place from the start; procurement can launch them today.

Step One: Tier your suppliers. Using procurement spend and carbon-emission contribution, sort suppliers into A, B, and C tiers. As a rule of thumb, the top 20% of suppliers contribute over 80% of supply chain carbon emissions. Focus your efforts on this 20% first; handle the rest later. You don’t have to do it all at once.

Step Two: Embed carbon-data disclosure clauses in contracts. When signing new contracts or renewals, add clauses requiring suppliers to provide carbon data. The first year’s threshold can be set low—requiring only total energy consumption and primary raw-material usage, not necessarily a complete product carbon footprint. The point is to make “providing carbon data” part of the business relationship, rather than the supplier “doing you a favor.”

Step Three: Have a fallback for data gaps. For suppliers who can’t provide first-hand data, substitute with industry averages or public databases (CPCD, Ecoinvent) for now. But you must annotate the data quality level in the report and set a timetable for progressively replacing it with measured data over the coming years. Allow gaps, but don’t allow pretending there are no gaps.

Step Four: Close the loop with cross-verification. Cross-check the carbon data suppliers provide against procurement volumes, logistics documents, and energy invoices. This step looks technical, but in practice it’s something procurement can do by verifying purchase volumes and logistics by verifying energy consumption. What you should fear most isn’t inaccurate numbers—it’s numbers that don’t reconcile with one another.

The spirit of this four-step method is consistent with my earlier breakdown of California’s SB 253 supply chain: turning abstract climate policy into small adjustments to everyday work like procurement, contracts, and documentation.

International Certifications Aren’t Awards—They’re the Buyer’s Outsourced Risk-Control Tool

A final point that’s easily misunderstood is international certification.

ISCC, EcoVadis, SBTi, CDP—many companies treat these as “awards,” getting a certificate to hang on the wall and viewing it as an honor. In reality, they were never awards. They are the buyer’s outsourced risk-control tool.

For an international brand, the longer the supply chain and the more cross-border links it has, the higher the cost of auditing each supplier individually. A market-recognized certificate is essentially not about praising the company—it’s about telling the buyer: “This company has at least passed one round of relatively standardized external review; working with it carries lower cost and more controllable risk.”

So the value of international certification isn’t in proving the company is great—it’s in making the company easier for buyers to incorporate into the supply chain.

This perspective matters, because it determines how you approach certification. If you treat certification as an award, you’ll chase as many as possible to look impressive. If you treat it as a market-entry ticket, you’ll pick the one buyers actually look at and do it thoroughly, concentrating your resources. For most Taiwanese SMEs, the ROI of the latter is far higher.

Three Implementation Paths: From 90 Days to 24 Months

If you’ve read this far and feel “this is a lot of pressure, and I don’t know where to start,” then you’re actually already ahead of many people. I’ve divided the things you can act on into three time horizons:

Short term (90 days): Complete the tiering of your top 20% suppliers, and write carbon-data disclosure clauses into your procurement contract template. These two things don’t necessarily require a consultant or a large budget; what they really require is putting the issue on the meeting table and making a management decision.

Medium term (6 months): Build your company’s own emission-factor ledger, and progressively replace Ecoinvent / GaBi with local databases. This step pushes carbon data sovereignty from “depending on others” toward “having your own cards to play.”

Long term (12–24 months): From among key tools like an SBTi target commitment, an EPD, or ISCC EU, pick the one most critical to your industry, do it thoroughly, and work toward being included on downstream brands’ lists of qualified green suppliers.

These three horizons aren’t a rigid SOP—they’re a pace of progress. Companies of different industries and scales can adjust the order, but you can’t pretend this isn’t going to happen. Once CBAM truly kicks in, companies that haven’t prepared will be quietly squeezed out of the supply chain within three years—no one will send you a special email to notify you; one day, the next order simply won’t be renewed.

Carbon Data Is a Company’s Credit Score

Let’s return to that aluminum-extrusion boss’s question at the very beginning: “We don’t directly export to the EU—does CBAM have anything to do with us?”

The answer was given at the very start of the article, but I’d like to close with another sentence:

What CBAM is really doing is turning carbon emissions—something once hidden inside factories where no one could see it—into an institutional object that can be externally audited, contractually managed, and priced. Whoever first builds a credible carbon data system holds their own bargaining chips in this reshuffled supply chain game. Whoever keeps waiting for others to tell them what to do can only accept the position others define for them.

Carbon emissions are no longer just an environmental issue—they will become a company’s credit score.

And your credit score can ultimately only be proven by your own data.

📌 SSBTi Official Position Statement

On the issues of “carbon data,” “carbon pricing,” and “corporate internal carbon-reduction strategy” addressed in this article, the relevant SSBTi official position was formally released by Chairman Raymond Wang (汪瑞民) on 2026-05-12: “Carbon credits are not carbon reduction; corporate management and third-party verification are what truly deliver net-zero carbon reduction.” For the full argument, see the SSBTi Facebook public post and the SSBTi website. This article is an extension of the author’s personal observations as an SSBTi circular economy partner; its argumentative direction is consistent with SSBTi’s position, but the specific wording and examples reflect the author’s own writing judgment.

This article takes as its starting point a CBAM analysis released by the CPCD community and edited by SSBTi, combined with extended observations by the author as a circular economy partner of SSBTi (the 1.5°C Science-Based Carbon Reduction Initiative Standards Association). The SSBTi mentioned in the text is a Taiwanese local association, while SBTi refers to the international Science Based Targets initiative—these are two different organizations. For CBAM policy content, please refer to the official page of the EU Directorate-General for Taxation and Customs Union.