A 5-ton single girder crane at medium duty burns more in electricity over ten years than the crane costs to buy. Here is where that power goes, what the motors actually draw, and which fixes pay for themselves.
A 1 to 20 ton single girder crane costs somewhere between USD 190 and USD 6,300 a year in electricity, and the spread is set more by duty class than by capacity. At A5 duty over ten years, the power bill for a 5-ton crane passes the purchase price of the crane. Roughly 62 percent of the consumption sits in the hoist, and most of the energy that could be recovered is thrown away during lowering.
This is the one cost line that buyers almost never put in the comparison sheet. Price gets quoted, installation gets quoted, spare parts get a budget. Electricity gets a shrug, because nobody has a number for it at the enquiry stage. Then the plant runs the crane for five years and the maintenance manager starts asking why the sub-meter on that bay keeps climbing.
What follows is our attempt to put real numbers on overhead crane energy consumption for single girder machines. Where the power goes by motion, what the motors actually draw by capacity, how to work out your own cost per hour, what regenerative drives really recover, what the EU motor regulation now requires, and which of the usual fixes have a payback shorter than the crane's service life. Some of the tables are drawn from published studies and vendor data, and we say which. The rest are our own planning figures, and we mark them as such rather than dressing them up as statistics.
Not evenly, and not where most people assume.
The measured breakdown for a workshop overhead crane puts the hoist at roughly 62 percent of total energy consumed, bridge or gantry travel at 31 percent, and trolley travel at the remaining 7 percent. Those figures come from the simulation and measurement work published in Energies 2024, volume 17, issue 5, article 985, which in turn draws on instrumented crane measurements including the share of energy that can be recovered from each motion.
The recovery column is the part that matters commercially, and it is lopsided:
| Motion | Share of energy consumed | Share of energy recoverable |
|---|---|---|
| Hoist - lifting and lowering | About 62% | About 81.5% |
| Bridge / gantry travel | About 31% | About 3.7% |
| Trolley travel | About 7% | Small |
So the hoist consumes most of the energy and accounts for nearly all of the recoverable part. Any efficiency project that does not start at the hoist is working on the wrong end of the machine.
There is a caveat worth stating, because the same study shows the opposite result for a different crane type. On a rail-mounted container gantry, gantry travel can be 79 to 89 percent of consumption, because that machine runs 100 metres or more along a stack each cycle. On a single girder crane in a workshop, the bridge moves a few tens of metres at most and the hoist does the real work. If you are reading energy figures off a port crane study and applying them to your assembly bay, the numbers will not transfer.
Instrumented measurements from a hot strip mill hoist, published by Mercu Buana University, show how much load matters at the machine level: the same hoist drew 197.2 kWh per day running unloaded and 340.1 kWh per day under load, a 72 percent increase. Idle and light-load running is not free either.
Three motors do the work, or four if you count both bridge drives. Most buyers only ever see the hoist rating on the quotation, which is why energy estimates go wrong by a factor of two.
A rough industry rule for the hoist itself: crane hoists in the 10 to 50 ton range need 7.5 to 75 kW motors, and gantry travel drives run 2.2 to 15 kW per drive wheel. A 20-ton hoist with four-part reeving, a 20:1 gearbox and 8 m/min lifting speed typically needs 15 to 18.5 kW at S4 40 percent duty, or a 22 kW inverter-duty motor if it is on a variable frequency drive and you want margin for acceleration and regenerative braking.
For a single girder crane in the capacities we build most often, these are the installed motor ratings we work from:
| Capacity | Hoist motor | Trolley motor | Bridge travel motors (2) | Installed output |
|---|---|---|---|---|
| 1 t | 1.5 kW | 0.4 kW | 2 x 0.4 kW | 2.7 kW |
| 2 t | 3.0 kW | 0.4 kW | 2 x 0.4 kW | 4.2 kW |
| 3.2 t | 4.5 kW | 0.4 kW | 2 x 0.75 kW | 6.4 kW |
| 5 t | 7.5 kW | 0.75 kW | 2 x 0.8 kW | 9.85 kW |
| 10 t | 13 kW | 1.5 kW | 2 x 1.5 kW | 17.5 kW |
| 16 t | 18.5 kW | 2.2 kW | 2 x 2.2 kW | 25.1 kW |
| 20 t | 22 kW | 2.2 kW | 2 x 2.2 kW | 28.6 kW |
Those are hoist motor output ratings, not consumption. Add losses and the input power is higher, which is the next step.
Four steps, and you can do all of them from a quotation and an electricity bill.
First, add the installed motor output. For a 5-ton single girder crane that is 7.5 plus 0.75 plus two bridge motors at 0.8 kW, so 9.85 kW.
Second, divide by motor efficiency to get input power. An IE3 motor running around 75 percent of rated load sits near 87 percent efficiency, which turns 9.85 kW of output into roughly 11.3 kW drawn from the supply. On older IE1 or IE2 motors, use 80 to 84 percent and expect a visibly larger number.
Third, multiply by equivalent full-load hours. This is where most estimates fall apart, because a crane almost never runs at rated load for whole shifts. Equivalent full-load hours are the motor running hours multiplied by the average load fraction. For planning we use 500 hours a year for A3 light duty, 900 for A4 medium-light, and 1,600 for A5 medium. Those are our planning figures, not measurements, and a two-shift operation will exceed them.
Fourth, multiply by your tariff. If you do not know your industrial rate, USD 0.12 per kWh is a reasonable international blend and is what we use below.
So the 5-ton crane at A4: 11.3 kW input times 900 equivalent full-load hours gives 10,170 kWh a year. At USD 0.12 that is about USD 1,220, or roughly USD 0.68 per operating hour assuming 1,800 hours on shift.
That per-hour number is the one worth comparing against a labour rate. A 10-ton crane at A5 works out near USD 2.15 per operating hour, before maintenance.
Running the same method across the range, at USD 0.12 per kWh:
| Capacity | A3 light - kWh/yr | A3 cost/yr | A4 - kWh/yr | A4 cost/yr | A5 - kWh/yr | A5 cost/yr |
|---|---|---|---|---|---|---|
| 1 t | 1,550 | USD 190 | 2,790 | USD 335 | 4,960 | USD 595 |
| 2 t | 2,400 | USD 290 | 4,320 | USD 520 | 7,680 | USD 920 |
| 3.2 t | 3,700 | USD 445 | 6,660 | USD 800 | 11,840 | USD 1,420 |
| 5 t | 5,650 | USD 680 | 10,170 | USD 1,220 | 18,080 | USD 2,170 |
| 10 t | 10,050 | USD 1,205 | 18,090 | USD 2,170 | 32,160 | USD 3,860 |
| 16 t | 14,450 | USD 1,735 | 26,010 | USD 3,120 | 46,240 | USD 5,550 |
| 20 t | 16,450 | USD 1,975 | 29,610 | USD 3,555 | 52,640 | USD 6,320 |
Those are SIEC planning figures built on the motor ratings above, 87 percent motor efficiency and USD 0.12 per kWh. If your rate is 0.20 USD per kWh rather than 0.12, scale everything up by two thirds.
Now stretch it over a service life, with electricity escalating 3 percent a year:
| Capacity and duty | 10-year energy cost | Typical crane price band |
|---|---|---|
| 1 t, A3 | USD 2,130 | USD 4,200 - 6,500 |
| 5 t, A4 | USD 14,000 | USD 10,500 - 16,000 |
| 5 t, A5 | USD 24,900 | USD 10,500 - 16,000 |
| 10 t, A5 | USD 44,200 | USD 18,000 - 28,000 |
| 20 t, A5 | USD 72,400 | USD 32,000 - 48,000 |
Read the middle column against the right one. At A4, energy over ten years is roughly the price of the machine. At A5 it is one and a half to two times the price of the crane. That is the reason a medium-duty duty class on the enquiry form is worth more attention than most buyers give it, and it is also why a machine ordered at A3 but run at A5 ends up quietly expensive.
Because a lowering load is a generator that nobody wired up.
Lift five tonnes eight metres and you have put about 392 kilojoules of potential energy into the load. Lower it again and that energy has to go somewhere. On a conventional hoist with a dynamic braking resistor, it goes into a grid of resistors as heat. The fan on the brake resistor runs, the cabinet gets warm, and the kWh meter keeps turning even though the motor is doing no useful work.
The scale of it is bigger than most people expect. Lowering a loaded hoist generates 60 to 80 percent of the rated hoist power as recoverable energy. A 50-ton hoist lowering at 5 m/min produces roughly 41 kW of regenerative power. At 500 cycles a day with a 15-second lowering phase, that is about 85 kWh recoverable per day, worth USD 2,500 to USD 4,500 a year on a single crane at a 0.10 USD per kWh blended rate.
Braking is not a rare event in a crane duty cycle either. It occupies 20 to 40 percent of the operating cycle once you count hoisting, trolley travel and bridge travel together. Almost half the machine's life is spent in the phase where a standard drive is converting momentum into heat.
Two different questions get bundled together here, and they have different answers.
The first is whether replacing contactor control with a variable frequency drive saves energy. Partly, and indirectly. A VFD removes the hard start each time the contactor closes, cuts the current spike, and lets the hoist run at the speed the job needs instead of at full speed or nothing. Published figures put the combined effect of a regenerative VFD and power factor correction at 25 to 40 percent lower crane energy consumption, with utility demand charges down 15 to 30 percent.
The second question is whether a regenerative drive does better than a dynamic-brake drive. This one has a clearer answer, because it is a measurable recovery rather than a duty-cycle effect. Replacing the braking resistor with a unit that feeds energy back to the plant supply recovers 20 to 35 percent of the hoist motion's energy and 15 to 25 percent of the horizontal travel energy.
Costs and payback for the main configurations, based on vendor data for A6 to A8 duty at 200 to 500 cycles a day, 2,000 operating hours a year and a 0.10 USD per kWh blended rate:
| Configuration | Capital cost | Annual energy saving | Payback |
|---|---|---|---|
| Dynamic brake VFD (baseline) | USD 8,000 - 15,000 | None recovered | n/a |
| Regenerative VFD, DC bus plus one regen unit, three motions | USD 14,000 - 25,000 | USD 2,500 - 6,500 | 2.5 - 4.5 years |
| Active front end regenerative drive, per crane | USD 18,000 - 32,000 | USD 3,500 - 8,500 | 2.0 - 4.0 years |
| Active front end plus active power factor correction | USD 22,000 - 40,000 | USD 4,000 - 10,500 | 2.5 - 4.0 years |
| Shared DC bus with active front end, four-crane bay | USD 45,000 - 75,000 | USD 12,000 - 28,000 | 2.0 - 3.5 years |
Those paybacks assume heavy A6 to A8 duty. At A3 to A5, with fewer cycles and less lowering time, the same hardware stretches to four to six years, or longer. For A5 duty with 80 to 120 cycles a day, a hoist-only regenerative retrofit typically costs USD 9,000 to 14,000 and returns USD 1,800 to 3,200 a year, which is a 3.5 to 6 year payback. Adding regeneration to all three motions at the same duty takes the capital to USD 18,000 to 28,000 against USD 2,500 to 4,500 a year.
Two practical notes from retrofits we have been involved in. If the existing drives already share a DC bus, a line-regenerative unit can be added in parallel and the individual drives stay. If each motion has its own isolated drive, the cost-effective move is usually to retrofit the hoist only and leave the bridge and trolley as they are, because the hoist is where 70 to 80 percent of the recoverable energy sits.
Compliance for this kind of work is usually checked against IEC 61800-5-1 for the drive's safety requirements, IEC 60204-32 for the crane's electrical equipment, and EN 15011 where a European declaration applies. Have a qualified electrical engineer confirm DC bus compatibility and control isolation before anything is ordered.
If the crane is going into the EU, or being built by a supplier who sells into the EU, motor efficiency is no longer a buyer preference. It is a legal floor, and it has moved twice.
Under EU Regulation 2019/1781, from 1 July 2021 three-phase motors rated 0.75 kW to 1,000 kW with 2, 4, 6 or 8 poles must reach at least IE3 efficiency. Motors between 0.12 kW and 0.75 kW must reach at least IE2. From 1 July 2023, three-phase motors in the 75 to 200 kW band with 2, 4 or 6 poles must reach IE4, but the regulation carves out brake motors and explosion-protected motors from that higher tier.
That exemption matters for cranes. Hoist and travel motors are normally brake motors, so they stay at IE3 rather than IE4. The IE4 band also sits above most single girder hoist ratings, where a 22 kW motor is already at the top of the range.
What the difference is worth, at 50 Hz, for four-pole motors:
| Rated output | IE3 minimum efficiency | IE4 minimum efficiency | Loss reduction |
|---|---|---|---|
| 1.1 kW | 84.1% | 87.2% | About 19% |
| 4 kW | 88.6% | 91.1% | About 22% |
| 11 kW | 91.4% | 93.3% | About 22% |
| 22 kW | 93.0% | 94.5% | About 21% |
| 55 kW | 94.6% | 95.4% | About 15% |
A 22 kW motor moving from IE3 to IE4 cuts its own losses by around a fifth. On a crane where that motor runs maybe 200 hours a year at load, the saving is real but small, and the money is better spent on regeneration. The efficiency class becomes decisive when the crane runs two or three shifts, or when the plant has a kWh-per-tonne target to hit.
One trap worth knowing. A motor that satisfies IE3 on a test bench can miss the target in service if it is oversized and running at 30 percent load, because efficiency falls away at low load. Right-sizing the hoist motor does more for the energy bill than buying a better efficiency class on a motor that is too big.
It changes what you can buy, and occasionally it changes the bill in ways nobody planned for.
Most single girder cranes we ship are quoted for one of three supply arrangements: 380 to 415 V at 50 Hz for Europe, the Middle East and much of Asia, 460 to 480 V at 60 Hz for North America, and 380 V or 415 V at 50 Hz for specific national grids. The differences that matter in practice are tolerance, duty definitions and service factor.
| Item | NEMA practice | IEC practice |
|---|---|---|
| Voltage tolerance at the motor | Plus or minus 10% | Zone A plus or minus 5%, zone B plus or minus 10% |
| Frequency tolerance | Plus or minus 5% | Plus 3% / minus 5% in zone B |
| Service factor | Recognised, commonly 1.15 | Not recognised |
| Duty definition | Continuous rating plus service factor | Duty types S1 to S10, declared by the buyer |
| Efficiency on the nameplate | Reference value | Roughly 0.3 percentage points higher for the same design |
The service factor point causes more trouble than it should. A NEMA 1.15 service factor does not mean you can run a crane 15 percent overloaded for its whole life. It means the motor can carry that load occasionally without failing immediately, at the cost of running hotter and shortening bearing and insulation life. IEC does not offer the concept at all, and instead asks the buyer to declare a duty type. If a quotation offers a service factor as a substitute for duty classification, ask what the duty class is.
The efficiency nameplate discrepancy is also worth remembering. An IEC motor and a NEMA motor of the same physical design can differ by about 0.3 percentage points on the label because of how the test standard is applied. That is inside the noise for any real energy calculation, but it does mean you should not compare two quotations on nameplate efficiency alone across standards.
Industrial tariffs rarely bill on kWh alone. Most add a demand charge based on the peak kVA you pull, and many add a penalty once power factor drops below a threshold, commonly 0.95.
The reason it matters on a crane is that inductive motors draw reactive current to make their magnetic fields. That current does no work but the utility still has to generate and deliver it. At 70 percent power factor it takes 142 kVA of capacity to deliver 100 kW of real power. At 95 percent power factor it takes 105 kVA for the same 100 kW.
A documented case from Eaton describes a commercial building paying a power factor penalty of USD 1,932 per month. Installing a capacitor bank cost USD 12,000 and paid back in a little over six months. Most utilities charge a penalty to any customer with three-phase service below the threshold, so a plant with several older contactor-controlled cranes and large motors can be paying this without anyone connecting the charge to the cranes.
Where utility demand charges exceed roughly USD 10 per kVAr per month, the economics of power factor correction improve enough to justify the work even on a single crane. Where the plant already maintains a good power factor, adding correction to a crane alone rarely pays.
Identical cranes cost very different amounts to run, and the tariff gap is larger than the efficiency gap between any two machines.
| Market | Industrial rate | Source and date |
|---|---|---|
| European Union | EUR 0.199 per kWh | BusinessEurope data hub, 2024 average |
| China | EUR 0.082 per kWh | BusinessEurope data hub, 2024 average |
| United States | EUR 0.075 per kWh | BusinessEurope data hub, 2024 average |
| China, industrial | CNY 0.571 per kWh | Intratec energy price series, January 2026, down 13.5% year on year |
| United States, industrial average | 9.17 US cents per kWh | US EIA Electric Power Monthly, June 2026 |
| United States, New York industrial | 10.17 US cents per kWh | US EIA Electric Power Monthly, June 2026 |
| United States, California industrial | 20.74 US cents per kWh | US EIA Electric Power Monthly, June 2026 |
The practical reading is blunt. The same 10-ton crane at the same duty class costs roughly two and a half times more to run in the EU than in the United States on the 2024 averages. European and Middle Eastern buyers on high tariffs should look hard at regenerative drives for any crane above A4, because the payback shortens in proportion to the tariff. Buyers in low-tariff markets should spend the same money on duty class and right-sizing, where it is not recoverable later.
Where two plants in the same country still see different costs, the difference is usually demand charges and power factor rather than the energy rate. Ask for twelve months of electricity bills and look at the kVA line before trusting any energy rate quoted on a specification sheet.
Ranked by what we see actually get implemented, with the payback we would expect in a workshop running one or two shifts:
| Measure | Typical saving | Typical cost | Payback |
|---|---|---|---|
| Right-size the hoist and shorten dead travel | 5 - 15% | Design change, no extra capex | Immediate |
| VFD on all three motions instead of contactor control | Part of the 25 - 40% combined effect | Specified at build, small premium | Under 2 years on a new crane |
| Power factor correction to 0.95 or better | Removes the kVAr penalty | USD 5,000 - 15,000 | 6 - 18 months where a penalty applies |
| Hoist-only regenerative drive retrofit | 20 - 35% of hoist energy | USD 9,000 - 14,000 | 3.5 - 6 years at A5 |
| Full three-motion regeneration | 20 - 35% hoist, 15 - 25% travel | USD 18,000 - 32,000 | 2.0 - 4.0 years at A6+ |
| IE4 travel motors in place of IE3 | About 20% of that motor's losses | Motor price premium | 3 - 6 years on multi-shift duty |
Two of those rows cost nothing but attention at the enquiry stage. That is not a coincidence. On a crane, the cheapest energy saving is usually the one designed in, and the most expensive is the one retrofitted after the machine has been installed on a runway that cannot easily be taken out of service.
So you can check our work rather than take it on trust.
Installed motor ratings are the typical European wire rope hoist figures we quote at each capacity, not measured values from a specific site. Input power uses 87 percent motor efficiency, which is a reasonable figure for an IE3 motor at around 75 percent load and optimistic for an old IE1 machine. Equivalent full-load hours are 500 for A3, 900 for A4 and 1,600 for A5, and those are our planning values based on lift counts and travel distance rather than measured duty. The tariff is a USD 0.12 per kWh international blend, and the ten-year figures escalate at 3 percent a year, which is close to long-run industrial electricity inflation in most markets but well below what several European buyers have actually seen since 2021.
Where a number comes from a published study or a vendor cost table, we say so in the text and in the table. Treat the ranges as planning inputs and replace them with your own tariff, duty class and lift counts before signing anything.
Between roughly 5,650 and 18,080 kWh a year depending on duty class. Light A3 duty at 500 equivalent full-load hours works out near 5,650 kWh, medium-light A4 near 10,170 kWh, and A5 near 18,080 kWh. That assumes the typical motor set for a 5-ton single girder crane, around 9.85 kW installed output at roughly 87 percent efficiency, giving about 11.3 kW of input power. Scale linearly with your own tariff.
Yes, but be clear about which effect you are counting. A regenerative drive recovers 20 to 35 percent of the hoist motion's energy and 15 to 25 percent of travel energy, which is a real measured recovery. Replacing contactor control with a drive at all adds duty-cycle and starting savings, and published figures for a regenerative VFD combined with power factor correction put total consumption 25 to 40 percent lower with demand charges down 15 to 30 percent. On light A3 duty with few cycles, the recovery is too small to pay back the hardware.
Usually, yes. If the existing drives share a common DC bus, a line-regenerative unit can be added in parallel and the existing drives stay in place. If each motion has an independent drive with no DC bus access, the practical approach is to retrofit the hoist drive only and leave the bridge and trolley alone, because the hoist holds 70 to 80 percent of the recoverable energy. Check drive and control compatibility before ordering, not after.
It generates. Lowering a loaded hoist converts potential energy into electrical energy at 60 to 80 percent of the rated hoist power. On a conventional hoist with a braking resistor, all of it is turned into heat and thrown away. A 50-ton hoist lowering at 5 m/min is producing about 41 kW at that moment, and over 500 cycles a day that is around 85 kWh recoverable daily. A single girder crane fitted with a regenerative drive sends most of that back to the plant supply instead of the resistor.
IE3 as a minimum for three-phase motors from 0.75 kW to 1,000 kW, under EU Regulation 2019/1781, since 1 July 2021. The IE4 tier that applies from 1 July 2023 covers the 75 to 200 kW band but excludes brake motors and explosion-protected motors, which means most crane hoist and travel motors stay at IE3. If a supplier cannot produce a motor test certificate for the efficiency class, that is worth treating as a gap in the compliance file.
Only if the utility charges for it. Where demand charges exceed roughly USD 10 per kVAr per month, or where the plant is carrying a low power factor penalty, correction can pay back in six to eighteen months. A documented case from Eaton saw a monthly penalty of USD 1,932 cleared by a USD 12,000 capacitor bank, a payback of a little over six months. Where the plant already runs above 0.95 power factor, correction on one crane rarely earns its cost.
If you are specifying a new single girder crane, the two things worth writing into the technical annex are the duty class and whether the hoist drive is regenerative. Those two lines decide most of the ten-year energy cost, and adding them later means replacing drives and cabling rather than ticking a box. Our 1 to 20 ton single girder range is quoted with both, and we will model the annual energy at your tariff on request.
If you want to see how the energy line compares with the rest of the ownership cost, the single girder crane cost and TCO guide breaks down purchase, installation and maintenance on the same basis.
Related articles:
Single Girder Crane Cost & Total Cost of Ownership Guide: 1 to 20 Ton Price, Installation, Maintenance & 10-Year TCO (2026)
How to Size a Single Girder Crane: Capacity, Span, Duty Class, Hoist Type & Supplier Spec Template
Single Girder Crane Standards 2026: CMAA 74, FEM 1.001 and EN 15011 Compared
Single Girder Crane Installation Guide 2026: 8-Stage Process, ISO 12488-1 Tolerances, Load Test & Cost
Crane Modernization vs Replacement: What the 2026 Numbers Say About Refurbishing Existing Cranes