A 39 per cent rise in diesel prices could increase total transport costs in inland waterway transport by between 5 and 9 per cent. This is the figure calculated by the Knowledge Institute for Mobility Policy (KiM) based on the price rise between February and April 2026, as reported by Nieuwsblad Transport and Schuttevaer via Headliner. The analysis was carried out in response to the situation in the Middle East and its impact on the energy market.
According to KiM, diesel cost approximately 1.81 euros per litre in the first week of February. By early April, this had risen to 2.52 euros, an increase of 39 per cent. To make the calculation, the institute looked at the share of fuel in total transport costs: in 2024, this stood at between 12 and 23 per cent for inland waterway transport, excluding push-boat transport. KiM bases its analysis on a scenario in which the higher diesel price is passed on directly to fuel costs.
Passing on the costs to the shipper
A higher diesel bill does not necessarily have to be borne entirely by the carrier. In freight transport, fuel clauses are used to pass on changes in fuel costs to customers. According to KiM, such agreements also exist in inland waterway transport and rail freight transport. The extent to which the increase is ultimately passed on to the shipper depends on the price agreements in place and the timeframe within which costs can be adjusted.
Impact on transport volume uncertain
The higher transport costs may also have consequences for transport volumes, although KiM emphasises that there is no precise, up-to-date estimate available. The institute therefore uses so-called elasticities: indicators that show how strongly demand responds to a price change. For inland waterway transport, this elasticity ranges from -0.28 to -2.6. Based on this, a cost increase of 5 to 9 per cent could lead to a reduction of 1 to 23 per cent in tonne-kilometres — a wide range derived from existing studies, and explicitly not a forecast by KiM. Moreover, the effect varies depending on the type of cargo and the distance travelled.
The figures involved are substantial. In 2025, international inland waterway transport consumed an average of around 71 million litres of marine diesel per month; domestic inland waterway transport stood at approximately 32 million litres. KiM points out that higher fuel prices will lead to behavioural change, particularly in the longer term, with potential consequences for transport flows and the use of fossil fuels.
Road transport also becoming significantly more expensive
Inland waterway transport is not alone in this. According to Transport Online, the Belgian transport federation Febetra warns of rapidly rising diesel costs in road transport: since 1 September, the price of commercial diesel has risen by 8.26 per cent, and compared with 1 January 2026, the increase now stands at 50.40 per cent. According to the Belgian institute ITLB, this is due to the resumption of air strikes on Iran.
The ITLB has calculated that, as a result, the total cost of general domestic road transport has risen by 8.71 per cent since January; for international transport, the increase stands at 8.12 per cent. Febetra describes passing on the higher fuel costs via a diesel clause as an “absolute must” and argues that the survival of transport companies would otherwise be at risk. The ITLB notes, however, that the cost indices as at 1 September do not yet reflect the subsequent price rises this month.
Implications for importers and exporters
The message for shippers is twofold. Yes, barge transport is becoming more expensive: the KiM figures show that the rise in diesel prices, passed on via fuel clauses, will sooner or later be reflected in inland waterway freight rates. But the figures also show that road transport is being hit just as hard — the total cost of a lorry journey has risen by over 8 per cent since January. Inland waterway transport’s relative position within the transport mix therefore remains intact: generally more cost-effective per tonne of cargo than road transport, and with lower CO₂ emissions per container carried.
However, caution is advised. When reviewing quotations, pay close attention to fuel clauses and surcharges, and bear in mind that rates may be adjusted in the interim as long as diesel prices fluctuate. Anyone planning shipments would be well advised to request a quotation in good time and to read the terms and conditions regarding fuel costs carefully. If you are unsure about the best mix of barge, rail and road for your cargo in this market, please ask for tailored advice.
in 2025, international inland waterway transport consumed an average of around 71 million litres of marine diesel per month? According to KiM, domestic inland waterway transport accounted for approximately 32 million litres per month. Every cent’s difference in price per litre therefore directly translates into millions of euros in fuel costs.
