That depends. Diesel, like crude oil, is sold globally, and Europe could look for new sources, such as the U.S., India or countries in the Middle East. If that goes smoothly, the impact on prices might be temporary and modest.
The EU’s top energy official, Kadri Simson, says markets have had time to adjust after the ban was announced in June. Europeans also appear to have stocked up on Russian diesel before the deadline, with imports rising last month. If the cap works as advertised, global diesel flows should reshuffle, with Europe finding new suppliers and Russian diesel finding new customers, without a major loss of supply.
“When Russian exports are constrained, for whatever reason, that would of course cause some trouble in this whole reshuffle process," said Hedi Grati, head of fuels and refining research for Europe at S&P Global Commodity Insights. “Europe would be competing with other big importers, and that would cause upward pressure on pricing.”