A one tonne combination crane carries about 6.2 tonnes of CO2e before it lifts anything, and 84 percent of that is in the track. Here is the mass per metre of every enclosed track profile, why aluminium track is not the low carbon option, what the modular rebuild argument is really worth, and how CBAM catches the track but not the crane.
A one tonne combination crane hanging from a factory roof carries about 6.2 tonnes of CO2e before it lifts anything, and 84 percent of that sits in the track it runs on. Not the hoist. Not the crane body. The track.
That number surprised me. I had spent two days arguing with a supplier about whether the aluminium profile should be anodised, and then ran the material take-off properly for the first time. The profile was the whole argument. The hoist was a rounding error.
Light modular systems get measured differently from heavy cranes, and the difference matters because most buyers assume light means low carbon. It does not work that way. Below is where the mass actually sits, why the aluminium option is not the green one, and what the modular sales pitch is really worth in tonnes.
Take a realistic installation. A 1 tonne double girder suspension crane serving a 24 by 40 metre bay, 18 metre bridge, 36 metres of travel per runway line. The track metres follow from the layout: two runway lines at 36 metres plus a double girder bridge of two 18 metre tracks. That is 108 metres of profile.
Everything else is small. A 1 tonne chain hoist with trolley is roughly 90 to 140 kilograms. End trucks add 30 to 50. Controls, cable and festoon add 30 to 60. Call the crane body 200 kilograms, which is generous.
Hangers are the item people forget. At 4.2 metre spacing on an A22-class profile, 36 metres of runway needs nine suspension points per line, so 18 hangers. At 6 kilograms each that is 216 kilograms of steel, more than the entire hoist and trolley.
| Item | Mass | CO2e | Share of system |
|---|---|---|---|
| Track, 108 m aluminium profile | 1,344 kg | 5.24 t | 84% |
| Hangers, 18 points at 6 kg | 216 kg | 0.51 t | 8% |
| Hoist, trolley, end trucks, controls | 200 kg | 0.47 t | 8% |
| Total, aluminium option | 1,760 kg | 6.22 t | 100% |
The same layout on plain cold rolled steel track comes out at 3.3 tonnes, with the track share dropping to 71 percent. Trussed steel lands in between the two. That gap between 3.3 and 6.2 tonnes is decided entirely by the profile, before anyone picks a hoist.
Crane makers publish capacity and suspension distances, not kilos per metre, which is why the numbers are hard to find. Gorbel does publish them, as weight per foot in its work station crane brochure, and the pattern is the same in every enclosed track system I have measured.
| Series and profile | Weight | kg per metre |
|---|---|---|
| 250 lb, plain steel | 2.53 lb/ft | 3.77 |
| 250 lb, aluminium | 4.05 lb/ft | 6.03 |
| 500 lb, plain steel | 4.15 lb/ft | 6.18 |
| 500 lb, trussed steel | 7.44 lb/ft | 11.07 |
| 500 lb, aluminium | 4.87 lb/ft | 7.25 |
| 1000 lb, plain steel | 6.22 lb/ft | 9.26 |
| 1000 lb, trussed steel | 12.25 lb/ft | 18.23 |
| 1000 lb, long truss | 14.08 lb/ft | 20.95 |
| 1000 lb, aluminium | 8.36 lb/ft | 12.44 |
Read the last four rows together, because that is where the sales argument gets slippery. Gorbel states that aluminium track weighs as much as 44 percent less than trussed steel track. Check the 1000 lb series: 8.36 against 14.08 is 41 percent lighter, so the claim holds. Against the standard truss it is 32 percent lighter. Against the plain steel profile of the same series, the aluminium track is 34 percent heavier.
That last comparison is the one nobody puts in the brochure. Aluminium is lighter than a truss, because a truss adds a second chord and web members on purpose. Aluminium is heavier than a plain cold rolled profile, because the material is a third the density but the section has to be much bigger to reach the same stiffness.
Per kilogram, aluminium is the more carbon intensive material by a wide margin, and the light-track advantage is not big enough to recover it. Two published anchors: worldsteel puts the global average steel at 1.92 tonnes CO2e per tonne in its 2025 Sustainability Indicators Report, with the blast furnace route at 2.34. European Aluminium reports 6.6 tonnes CO2e per tonne for European primary aluminium, 10.1 for the primary metal actually consumed in Europe, and 0.26 for remelted secondary metal, gate to gate.
For the planning numbers below I use 2.34 for steel and 3.9 for aluminium. The aluminium figure matches the CBAM default value for hollow aluminium profiles, which is the number a European importer will be asked to use if they cannot document actual emissions. It sits between the secondary and primary extremes.
| Track option | kg per metre | kg CO2e per metre | 108 m of track |
|---|---|---|---|
| Plain steel, 1000 lb | 9.26 | 21.7 | 2.34 t |
| Trussed steel, 1000 lb | 18.23 | 42.7 | 4.61 t |
| Aluminium, 1000 lb | 12.44 | 48.5 | 5.24 t |
So the aluminium track is 2.2 times the carbon of the plain steel profile per metre, and 14 percent more than the trussed steel it is marketed against on weight. At the low end, if the aluminium comes from secondary billet at 0.26 plus about 0.38 for extrusion, the same profile drops to roughly 0.6 tonnes CO2e per tonne and beats everything. That is a real route. It is also unverifiable from a purchase order, because nobody puts recycled content into a crane quotation.
I do not think this makes aluminium the wrong choice. Lower deadweight means lower push force, less wear on the trolley, and a cleaner running system, and those are genuine ergonomic wins. It just means the choice is not a carbon decision. If a buyer needs the carbon number to be low, the plain steel profile is the answer and the truss is what to avoid.
For a light system the track length is set by the bay, not by the load, and there is a simple formula worth carrying into every meeting: track metres roughly equal twice the travel length plus twice the span for a double girder, or twice the travel plus the span for a single girder.
| Bay | Track metres | Aluminium, 1 t | Plain steel, 1 t |
|---|---|---|---|
| 12 m travel, 12 m span | 48 m | 2.3 t | 1.0 t |
| 24 m travel, 15 m span | 78 m | 3.8 t | 1.7 t |
| 36 m travel, 18 m span | 108 m | 5.2 t | 2.3 t |
| 60 m travel, 20 m span | 160 m | 7.8 t | 3.5 t |
A 60 metre bay costs 3.3 tonnes more than a 36 metre bay with the same crane and the same load. That single line is worth more than every material decision in this article put together, and it is usually settled in an architectural drawing long before a crane supplier is called.
Suspension spacing is published by the manufacturers and it varies more than people expect. Demag lists, for a 1,000 kilogram load, 4.2 metres between suspensions on its A22 aluminium profile and 6.5 metres on the newer A28. On steel profiles the same span needs more support, which is why the truss exists.
| Spacing at 1,000 kg | Hangers over 72 m of runway | Hanger steel at 6 kg |
|---|---|---|
| 4.2 m, A22 profile | 18 | 108 kg |
| 6.5 m, A28 profile | 12 | 72 kg |
| 2.3 m, 2,000 kg on A22 | 32 | 192 kg |
Wider spacing saves 36 kilograms of steel here, which is 0.08 tonnes of CO2e. It is noise next to the profile decision. Where it stops being noise is the classification question, and this is the part that catches people out on a CBAM return.
A hanger is a clamp, a threaded rod and a bracket. A hollow steel tube is a CBAM good under 7306, with a published default of 2.687 tonnes CO2e per tonne. Bolted steelwork of the kind that a bracket belongs to falls under 7308, and the published default for other structures, parts and structures under 7308 90 98 is 6.374 tonnes CO2e per tonne. Same metal, 2.4 times the default value, decided by which heading the customs entry lands in. Our 216 kilograms of hangers is 0.51 tonnes of CO2e as tube and 1.38 tonnes as structure.
Modular systems earn their keep at junctions. A single crane can be handed from one bay to another through a switch, and a turntable lets a monorail turn a corner without a curve. Each of those components adds material at a point where the load path is least efficient.
| Component | Equivalent track metres | Extra CO2e |
|---|---|---|
| 90 degree curve, 1.2 m radius | 1.9 m, plus 35% fabrication scrap | 0.03 t |
| Switch with drive | 2.5 m plus 8 kg of motor and control | 0.15 t |
| Turntable | 3.0 m plus bearing and drive | 0.20 t |
Two curves and one switch came to 47 kilograms of extra profile in my take-off, about 0.18 tonnes of CO2e. Real, but not a decision driver. What a switch does change is the duty class, because handing a crane between bays concentrates cycles at one point, and the local reinforcement at that point is where the track wears out first.
Free compared with columns, yes. Free compared with nothing, no. A suspension crane transfers its load into the roof structure, and the roof was designed before anybody knew a crane was coming.
Demag is explicit that its Aluline suspensions hang from workshop ceilings or roof structures without additional columns, and Gorbel builds its whole ceiling mounted range on the same assumption. Both assume a structure that can take the point loads. If it cannot, you buy columns.
| Support choice | Added steel | Added CO2e |
|---|---|---|
| Hang from existing roof, local reinforcement | 150-400 kg | 0.35-0.94 t |
| Four new columns, 6 m, IPE 270 | 866 kg | 2.03 t |
| Four footings, 1.5 m3 each | 6 m3 concrete, 480 kg rebar | 2.9 t |
Columns plus footings come to 4.9 tonnes, which is 79 percent of the entire aluminium system above. A roof that was designed for a crane is the single most valuable thing a factory can own, and it is decided decades before anyone asks about carbon.
This one is usually argued on price and travel length, and the carbon question turns out to be small either way. Conductor bar weights are published by the manufacturers: a 5 pole enclosed bar in the 70 ampere class runs about 1.70 kilograms per metre, a 4 pole 40 ampere bar about 1.05.
| Power feed for 36 m of travel | Mass | CO2e |
|---|---|---|
| Festoon, flat cable, C-track and carriers | 55-70 kg | 0.05-0.10 t |
| Conductor bar, 5 pole, 1.70 kg/m | 61 kg | 0.18-0.24 t |
| Integrated conductor line inside profile | adds 8-15% to profile mass | 0.25-0.60 t |
The third row is the one worth pausing on. Putting the conductor line inside the profile is elegant, it removes the festoon loops and the collision risk that goes with them, and it is the reason some profiles exist in an -R version. It also adds 8 to 15 percent to the mass of every metre of that profile. Over 108 metres that is 0.25 to 0.6 tonnes of CO2e, more than the entire power feed it replaces.
None of this is a reason to reject an integrated line. If travel exceeds 80 metres, or the crane runs above a walkway, the collision argument wins and the carbon follows. On a 20 metre workstation run, festoon is cheaper and lighter, and the conductor bar's advantage of unlimited travel never gets used.
This is the comparison that reframes the whole subject. A 10 tonne single girder crane of the kind we build carries about 5.7 tonnes of steel and around 13.4 tonnes of CO2e at the blast furnace route. That is 1.34 tonnes CO2e per tonne of capacity.
| System | Capacity | Embodied CO2e | Per tonne of capacity |
|---|---|---|---|
| Combination system, aluminium track | 1 t | 6.2 t | 6.2 |
| Combination system, plain steel track | 1 t | 3.3 t | 3.3 |
| Single girder overhead, 16.5 m span | 10 t | 13.4 t | 1.34 |
| Double girder overhead, 22 m span | 20 t | 43 t | 2.2 |
Small cranes are carbon expensive per tonne lifted. That is not a defect, it is geometry: a track has a minimum practical section, a hoist has a minimum practical frame, and a 1 tonne system still needs 108 metres of profile because the bay is 40 metres long, not because the load is heavy.
Which also means the right question on a light system is not "how do I make the crane greener". It is "do I need this bay served by a dedicated track at all". One 5 tonne overhead crane serving three workstations through a shared runway will beat three 1 tonne combination systems on carbon every time, and lose on ergonomics.
This is where light systems genuinely win, and it does not show up in any single project's material take-off. Demag states that Aluline installations can be altered and extended at any time, and that profile sections can be removed and extended. Bolted connecting plates and end caps are the whole assembly method. The system is designed to be taken apart.
Compare that with a welded suspension crane built for one layout. When the line changes, the crane is cut up.
| Twenty year scenario | Embodied CO2e | Per layout served |
|---|---|---|
| Modular system, one layout, 20 years | 6.2 t | 6.2 t |
| Modular system, rebuilt twice, 3 layouts | 7.4 t including new brackets | 2.5 t |
| Three welded cranes, one per layout | 13.5 t | 4.5 t |
Rebuilding a modular system costs about 20 percent of its original carbon in new brackets and hangers, because the profile is reused, and the steel that gets scrapped from a welded crane usually goes for remelting rather than back into a crane. That is the real case for modular: not the material efficiency of the first installation, which is poor, but the fact that the second and third installations are nearly free.
For a light system it is close, and the answer depends on duty class more than on anything else. Take a 1 tonne system with 2.5 kilowatts of installed motor power across hoist, trolley and long travel. Running at a 35 percent demand factor over a two shift year gives 875 kilowatt hours, and 17,500 over twenty years.
| Duty and grid | 20 year kWh | 20 year CO2e |
|---|---|---|
| 1,000 h per year, EU grid at 206 g | 17,500 | 3.6 t |
| 2,000 h per year, EU grid at 206 g | 35,000 | 7.2 t |
| 1,000 h per year, China grid at 537 g | 17,500 | 9.4 t |
| 2,000 h per year, China grid at 537 g | 35,000 | 18.8 t |
The grid factors are from the European Environment Agency, which put EU electricity generation at 206 grams CO2e per kilowatt hour in 2024, and from China's 2022 national average power factor of 0.5366 kilograms per kilowatt hour. The duty assumption is the one to check: an A3 light system at 1,000 hours a year has operating carbon below its embodied carbon on a European grid. At A5 the two are level. On a Chinese or Indian grid the operating side wins outright regardless of duty.
Which is an odd conclusion for a light crane article. Efficiency work on a 1 tonne system is worth doing because the electricity is cheap to save and the payback is at the motor, not because the carbon is dramatic.
Yes, and it is the reverse of the situation with heavy cranes. A 5 to 100 tonne overhead crane is HS 8426, which is not in Annex I of Regulation (EU) 2023/956, so the crane itself triggers no CBAM obligation. A light system is mostly track, and track is a material.
These are the published default values from the UK's CBAM tables, released on 16 October 2026, which follow the same methodology the EU uses. The EU publishes its own set under Implementing Regulation (EU) 2025/2621 and the numbers differ in detail, so treat the ratios as the message rather than the digits.
| Item | CN code | Default value |
|---|---|---|
| Aluminium hollow profile for track | 7604 21 00 | 3.894 t per tonne |
| Aluminium solid profiles, alloy | 7604 29 90 | 4.014 t per tonne |
| Steel hollow profile for track | 7306 30 77 | 2.687 t per tonne |
| Steel structures and parts, n.e.s. | 7308 90 98 | 6.374 t per tonne |
| The crane itself | 8426 | not in scope |
Run the arithmetic on one system and the exposure looks small: 1,344 kilograms of aluminium track at 3.894 is 5.23 tonnes CO2e, and at the 2026 third quarter certificate price of 82.32 euros that is 431 euros gross. That is not a cliff edge for one machine. It becomes one for a distributor who imports thirty systems a year, because the 50 tonne annual threshold counts total mass of CBAM goods, and thirty systems at 1.8 tonnes of track each is 54 tonnes.
Two things follow. First, actual liability is not the gross figure, because free allocation benchmarks and any carbon price paid at origin both reduce it, so 431 euros is a ceiling rather than an invoice. Second, the classification of the track matters more than the crane ever did. A system shipped as a kit of hollow profiles is one thing. The same kit with brackets and frames classified under 7308 raises the default from 2.687 to 6.374 on that portion.
Ten lines, in the order that changes the answer most. Our own combination crane page lists the configurations we build; the list below is what to ask for regardless of who supplies it.
| Item to specify | Why it moves the number |
|---|---|
| Track metres, not bay size | Every metre is 21 to 49 kg CO2e, and the bay sets the metres |
| Profile type and mass per metre | Plain steel against trussed steel is a factor of two |
| Aluminium against steel, stated as a preference | Ergonomics yes, carbon no, so say which you are buying |
| Suspension spacing and hanger mass | Sets the roof loads and the bracket tonnage |
| Roof structure capacity, in writing | Avoids 4.9 tonnes of columns and footings |
| Switch, curve and turntable count | 0.2 tonnes each, and they concentrate wear |
| Power feed type and whether it is integrated | An integrated line adds 8 to 15 percent to profile mass |
| Duty class, A3 to A5, with hours per year | Decides whether operating carbon beats embodied |
| Rebuild capability, in writing | The 60 percent saving only exists if the system is reused |
| CN codes for the track and brackets | 7604 against 7308 is a 2.4 times difference in default value |
If you send only three of those lines, send the track metres, the profile mass and the roof capacity. The rest are refinements on top of a decision that three numbers already made.
Not where the marketing puts it. A combination crane is not a low carbon crane. Per tonne of capacity it is among the most carbon expensive machines in a factory, because it is mostly track and track is built from a minimum practical section rather than from load.
What it is good at is adapting. If the production line changes every five years, and most lines do, a bolted modular system spreads its embodied carbon across three layouts while a welded crane gets cut up after one. That is worth 2 to 4 tonnes of CO2e per rebuild, and it is the only argument in this article that survives contact with a real project.
I would still specify plain steel profiles when carbon is the deciding criterion, and aluminium when the operator's shoulders are. Those are different problems, and the industry has spent a decade pretending they are the same one.
Per tonne of lifting capacity, no. A 1 tonne combination system comes out around 3.3 to 6.2 tonnes CO2e, which is 2.5 to 4.6 times the 1.34 tonnes per tonne of a 10 tonne single girder overhead crane. Per installation the light system is smaller, because it is a smaller machine serving a smaller area. The two numbers get confused constantly in tender documents.
Not at the same capacity. Aluminium extrusion carries 3.894 tonnes CO2e per tonne by default against 2.687 for steel hollow sections, and the aluminium profile is 34 percent heavier per metre than a plain steel profile of the same series. The result is 48.5 kilograms CO2e per metre against 21.7, so the aluminium option is 2.2 times the carbon. It is lighter than trussed steel and roughly equal to it in carbon. The one route that beats steel is secondary aluminium, at about 0.26 tonnes CO2e per tonne for remelt plus extrusion, and that cannot be verified from a quotation.
Between 70 and 85 percent for a normal bay. On a 1 tonne system over 108 metres of profile, the track is 84 percent of the total for aluminium and 71 percent for plain steel. The hoist, trolley, end trucks and controls together are under 10 percent. Hangers are 8 percent, and can be more than that if the customs entry puts brackets under 7308 rather than 7306. Our combination crane range is built around this reality, which is why the profile schedule is agreed before the hoist.
To the track, yes, and to the crane, no. Cranes are HS 8426 and sit outside Annex I of Regulation (EU) 2023/956. Aluminium hollow profiles 7604 21 00 and steel hollow profiles 7306 30 77 are both inside it. A single 1 tonne system carries about 5.2 tonnes of CO2e in aluminium track, which at the 2026 third quarter certificate price of 82.32 euros is 431 euros of gross exposure before free allocation. The 50 tonne annual threshold for authorised declarants counts all CBAM goods combined, so a distributor importing thirty systems a year crosses it.
It does, and this is the strongest argument for the category. Rebuilding a bolted system into a new layout costs about 20 percent of its original embodied carbon, mostly new brackets and hangers, because the profile is reused. Three welded cranes for three layouts over twenty years come to 13.5 tonnes against 7.4 tonnes for one modular system rebuilt twice. The saving is in the second and third layouts, not the first.
It depends on duty class and grid. On a European grid at 206 grams per kilowatt hour and 1,000 hours a year, operating carbon over twenty years is 3.6 tonnes against 6.2 tonnes embodied, so the track wins. At 2,000 hours a year the two are level at 7.2 against 6.2. On a Chinese grid at 537 grams, operating carbon is 9.4 tonnes at the lower duty and 18.8 at the higher, and the electricity wins outright. If you are choosing between a second hoist and a lighter profile, look at the hours first. A double girder overhead crane in the same bay would change the arithmetic again, because it carries its own runway.
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