Energy Aspects' Amrita Sen said that the European Union wouldn't purchase Russian oil even if there was a price cap.
The EU will no longer allow imports of seaborne Russian oil. Insurance and shipping services for Russian oil will not be provided by EU-based companies.
A price cap on Russian oil will prevent a price shock while limiting Moscow's export revenue as a result of the EU embargo.
EU countries can still import Russian oil if they stick to the price cap.
The embargo by the EU on the 5th of December supersedes the price cap." Sen said in an interview that the EU will stop buying Russian oil even if the price is capped.
She said that markets were confused about what the price cap meant for supply.
She acknowledged that markets should wait to see what happens on December 5 in order to make sure that the EU follows through on its ban.
Russia has warned that it won't sell its crude to any nation that participates in the price cap, and analysts doubt that Moscow's top oil customers will go along with it.
Russia is threatening to take its supplies off the spot market and cause a price spike.
Because of the EU's leading position as a worldwide provider of financial services for the oil trade, next month's round of sanctions on Russia could potentially affect shipments outside of the EU.
After December 5, participants in the price cap can still send oil from Russia. Not many countries have pledged to work together, and non-EU companies can provide financial services for Russian oil.
Sen said that no one else besides the G7 has accepted it yet.