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Developments in sodium-ion batteries have come from a brand new era of cells from CATL, BYD, and others, bringing the opportunity of decrease cells prices at larger quantity within the close to future. CATL has acknowledged it expects oceanic electrical ships to be attainable within the subsequent three years. May $20/kWh Naxtra sodium-ion batteries assist electrical ships attain value parity with diesel at oceanic distances within the close to future? To search out out, we have to know ship power consumption and velocity and modify for anticipated battery efficiency within the subsequent three years, the subsequent Naxtra battery era.
“Container ships elevated their common velocity by 1% in comparison with 2023, reaching 14.0 knots.”
Gasoline consumption will increase with the dice of velocity. The info exhibits a 5,000 TEU Panamax container ship consumes about 50 tons of gasoline per day at 17 knots. We are able to calculate outcomes for this dimension ship crossing the Atlantic from Rotterdam to New York.
Rotterdam–to–New York Vitality Consumption
The Rotterdam to New York sea route distance is 3,323 nm, which is 5,556 km. If a ship travels at 17 knots, it’s going 19.56 mph, or 31.484 km/h. Over 5,556 km, it will take 176.5 hours, or 7.35 days, to cross the Atlantic to its vacation spot (5,556 km/(31.484 km/hr)). With gasoline consumption of fifty tons/day, a ship makes use of 367 tons of gasoline per journey (50 t/day x 7.35 days). The decrease calorific worth of HFO is 39 MJ/kg.
1,000 kg = 1.102311 ton
1MJ = 0.27777 kWh
39 MJ/kg x 1,000 kg/1.1023 ton x 0.27777 kWh/MJ = 9,828 kWh/ton for HFO
With combustion effectivity of 0.5, that delivers 4,914 kWh/ton, or 4.914 MWh/ton, on the propeller shaft. For 367 tons of gasoline, 367 tons x 4.914 MWh/ton = 1.803 GWh. With an electrical motor effectivity of 0.9, the determine for power storage required is 2.00 GWh for a 5,556 km route from Rotterdam to New York at 17 knots.
Battery Quantity vs. Gasoline Quantity
A 5,000 TEU Panamax container ship can have 2 million gallons of gasoline storage. 2 e 6 gal x 3.78 liter/gal x 0.001 cubic meter/liter = 7,560 cubic meters. For 33.1 m3 per TEU, this represents an equal of seven,560 cubic meter/[33.1 cubic meter/TEU] = 228 TEU Gasoline Quantity Equal.
If power storage containers are 10 MWh/TEU, then it takes 200 TEU (2,000 MWh/10 MWh).
At 33.1 cubic meter/TEU, the amount will likely be 6,620 m3.
Containerized Battery Vitality Storage (BESS) specification varies. Utility storage BESS requirements differ from marine BESS, as a result of they might be used for grid peak demand over quick intervals lower than one hour at excessive cost charges and require excessive cycle life. China is now utilizing a 2 MWh marine TEU container customary not optimized for quantity. Onshore BESS could be present in 5 MWh BESS 20 foot containers. Lithium utility storage BESS commerce power density for value per kWh and cycle life. Land-based LFP utility storage should maintain temperature in a slim vary close to 30°C to achieve 4,000 cycle life. LFP cells use thicker electrodes and decrease power density to optimize value per kWh. As a result of utility storage BESS wants lively cooling, it delivers much less power per TEU container. Thermal administration consumes house and power and will increase weight. Sodium-ion BESS in ships could be passively cooled and densely packed. Calculations present Naxtra SIB cell volumetric power density has elevated and will match current day LFP, as a result of it has a self-forming anode. Current day LFP is 434 Wh/l.
SIBs at $20/kWh are projected in about 3 years. By then, gravimetric power density will enhance from 175 Wh/kg to 200 Wh/kg, and by ratio, the volumetric power density will likely be 484.6 Wh/l (200/175 x 434 Wh/l).
Ships don’t want excessive cycle life. For five,000 km distances, ships journey in about 8 days. Over a 12 months, a 5,000 km vary ship may cycle 40 occasions. Over a 25 12 months ship lifetime, that’s only one,000 cycles, simply met by most batteries, and enormously exceeded by sodium-ion battery 10,000 cycle lifetimes. For lengthy journeys, battery inside dissipation is miniscule. Losses are primarily motor electronics and management. Sodium-ion has a C of 5. Battery period is 1 hr/5, or 12 minutes. Journey time is 176 hours. That could be a discharge price of 176 hours. Software period/rated period = 176/0.2 = 880. On this lengthy period electrical ship instance, present is 880 occasions lower than battery ranking. Battery inside resistance losses are decreased by present squared, giving negligible inside dissipation. Vitality storage will likely be close to ambient temperature with passive cooling. Along with larger temperature vary and security, sodium-ion requires little house for passive cooling.
Battery Electrical Propulsion Quantity In comparison with Diesel
Given 484 Wh/l
2,000,000 kWh/ (0.484 kWh/l) = 4.132 e 6 litre
4.132 e 6 l x 1 e -3 cubic meter/l = 4,132 cubic meters
There are 33.1 cubic meters per 20 foot container (TEU)
4,132/33.1 = 125 TEU
Given 228 TEU gasoline quantity equal, there’s a internet theoretical lower in required quantity of 103 TEU required for sodium-ion. Max theoretical sodium-ion BESS TEU capability is roughly 16 MWh. Sodium-ion can simply exceed 5 MWh/TEU with passive cooling.
2,000 MWh/(10 MWh/TEU) = 200 TEU
200 TEU x 33.1 m3 /TEU = 6,620 m3
The web quantity utilizing 10 MWh sodium-ion BES containers is -940 m3.
The equal TEU of gasoline capability is determined by MWh/TEU. If 10 MWh/TEU, that provides 10 MWh/33.1 m3. The equal MWh for diesel gasoline quantity is 229 TEU. For 10 MWh/TEU and a pair of,000 MWh capability, 200 TEU are wanted. With 5 Wh/TEU, 400 TEU electrical storage is required, solely 171 extra TEU, lower than 3.5% of cargo quantity. Current day sodium-ion volumetric power density is sweet for about 400 Wh/l. That permits a theoretical most 13.24 MWh/TEU, ok for a ten MWh power storage container. For LFP and close to future Naxtra sodium-ion batteries with volumetric power density over 400 Wh/l, electrical ship power storage is restricted by TEU packing density, not cell volumetric power density. In ship purposes, volumetric advantages of passive cooling and low volatility are extra vital than cell power density metrics.
- 10 MWh power storage containers
- Motor and engine quantity are low. Exhaust and cooling weight and quantity variations are omitted. Electrical motor effectivity is larger than diesel, leading to decrease cooling necessities.
Electrical Motor vs Diesel Engine Weight
The load of a marine diesel engine is 2,100 mt.
The load of an electrical motor is 150 mt.
The distinction in motor weight is 1,950 mt.
Battery Weight vs Gasoline Weight
2,000 e 6 kWh/0.200 Wh/kg = 10.0 e 6 kg = 10,000 mt batteries
Panamax ships carry 2 million gallons of gasoline. Bunker gasoline is 3.7 kg/gallon. 2 e 6 gallons x 3.7 kg/gallon = 7.4 e 6 kg = 7.4 e 3 mt = 7,400 mt. Gasoline versus battery weight distinction is 10,000 mt – 7,400 mt = 2,600 mt. Diesel versus electrical motor weight distinction is -1,950 mt. The sum of complete weight variations is 2,600 mt – 1,950 mt = 650 mt. Electrical propulsion is barely heavier by 650 mt. Panamax ships weigh about 65,000 dwt. Loaded TEU containers weigh 24 mt. The surplus weight is the equal of about 220 containers, below 5% of attainable cargo TEU.
Opex Value
Gasoline Prices
Annual diesel gasoline value is computed from common international gasoline value for VLSFO (2025) at $570/metric ton. VLSFO is 11.28 kWh/kg, or 11,280 kWh/mt. At 48% effectivity, VLSFO delivers 5,400 kWh/mt. VLSFO prices $570/5,400 kWh = $10.56/kWh.
The US common industrial electrical energy price was $0.084/kWh in 2025. Everlasting Magnet Synchronous Machines (PMSG) for marine purposes function at 96% effectivity. Together with effectivity, this interprets to $0.0875/kWh saved. International industrial electrical energy costs range based mostly on tax insurance policies and authorized issues, generally unrelated to wholesale costs. Swappable power storage containers together with renewables can present $0.084/kWh with renewable era Energy Buy Agreements (PPA) for photo voltaic and wind at excessive utilization charges. A mix of current era and new renewables can present electrical energy for swappable power storage containers.
Touring 7.5 days, and in port 1.5 days to unload all 12 months, provides a 9 day cycle and 365/9 = 40.55 journeys per 12 months. 40 journeys/12 months x 2.0 e 6 kWh/journey x $ 0.1056 – 0.0875/kWh = $1.448 e 6/12 months electrical energy value distinction.
Upkeep Value
The annual upkeep value for lubricants, filters, monitoring, personnel, and overhauls is about $1 million a 12 months for a 5,000 TEU Panamax ship. Electrical upkeep value is almost zero. The entire opex value distinction is $2.5 million/12 months.
Capex
A 40,000 HP diesel prices $20–30 million. An electrical drivetrain prices about $100,000 per MW, and 40,000 hp is 30 MW. 30 MW x $ 0.1 million/MW = $3 million. Electrical motors and batteries have an extended life than marine diesels. Electrical mills can final a century or extra with little upkeep. The primary mills at Niagara Falls are nonetheless in working order 100 years later. 2,000 MWh x $20/kWh = $40 e 6, the capex for batteries.
Battery Electrical In comparison with Diesel
At $20/kWh, over 25 12 months life, the design examine electrical ship saves $16 million in current {dollars} over diesel resulting from decrease working prices. Diesel opex is bigger than extra electrical ship capex. Breakeven battery value is $56 million for two,000,000 kWh, or $28/kWh.
Battery Life
At 40 journeys per 12 months, and with cycle lifetime of 4,000 cycles, battery cycle life is 100 years. Battery calendar life can exceed 25 years. Diesel ship lifetime is 25 years. When larger battery and electrical motor lifetimes are thought-about, electrical ship value benefits widen over diesel.
Conclusion
Calculations present a cross-Atlantic journey of 5,500 km from Rotterdam to New York requires 2 GWh of electrical energy at 17 knots, whereas common container speeds are 14 knots. The examine instance oversizes the battery requirement by 1.78 on the larger velocity, permitting journey flexibility. On this state of affairs, modest near-future gravimetric power density will increase permit electrical ship batteries to make use of lower than 5% of cargo quantity and weight. With passive cooling and battery security, near-future SIB added battery quantity and weight are below 5% of cargo for ships of 5,000 TEU or extra, presenting a possibility to make use of container ships as power tankers.
Analysis exhibits diesel lifetime working prices are excessive in comparison with capital prices. A diesel engine can value $30 million, whereas annual working prices could be about $10 million. Excessive diesel working prices tip the scales in direction of battery electrical propulsion over a typical diesel ship lifetime. Diesel gasoline prices exceed electrical energy prices by $1.5 million yearly. Diesel annual upkeep prices could be $1 million, whereas electrical upkeep prices are minimal. At $20/kWh, batteries could be decrease value than diesel ship propulsion for five,000 km distances. BES versus diesel breakeven is at $28/kWh for five,500 km vary.
A current examine advised that over 40% of worldwide container ship quantity may very well be electrified with batteries at $50/kWh. With decrease prices and larger vary, battery electrical ships can do the vast majority of international container and bulk cargo ship quantity. Interregional routes from Singapore to Shanghai, and from North Sea to Mediterranean, are doubtless first purposes for five,000 km electrical ships. As calls for for decrease emission improve, diesel gasoline prices and propulsion capex prices improve. Decrease emission fossil fuels, scrubbers, hybrids, and artificial gasoline alternate options require extra prices, whereas renewables and battery prices fall. As battery prices fall, electrification presents a viable pathway to decrease emissions. For the reason that time of this writing, VLSFO prices have soared, tipping the scales additional towards electrification. Battery electrical benefits transcend value towards safety and reliability.
Replace
At at present’s VLSFO costs of about $750/mt, diesel gasoline costs rise in comparison with the state of affairs $570/mt. Diesel gasoline prices rise to $0.139/kWh. 2026 industrial electrical energy charges rise to $0.09/kWh, and after 96% effectivity is factored, $.0938/kWh. 40 journeys/12 months x 2.0 e 6 kWh/journey x $ 0.139 – 0.094/kWh = $ 3.6 e 6/12 months electrical energy value distinction. Along with the $1 million upkeep distinction, the entire is $4.6 million yearly. Over a 25-year lifetime at 4%, the current worth is $53.5 million. The surplus diesel value is $40.5 million. Breakeven battery value is $80.5 million for two million kWh, giving $40.25/kWh breakeven.
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