According to a report, Russia earned nearly $100 billion (£82.3 billion) from oil and gas exports during the first 100 days of the Ukrainian conflict.
Revenues have been declining since March as many countries avoided Russian supplies, but they remain high, according to the independent Centre For Research on Energy and Clean Air (CREA).
It also warned of potential loopholes in efforts to limit Russian imports.
The EU, US, and UK have all pledged to reduce Russian imports.
However, the CREA report found that Russia earned $97 billion in revenue from fossil fuel exports during the first 100 days of the Ukraine conflict, from February 24 to June 3.
The European Union accounted for 61% of these imports, worth approximately $59 billion.
Overall, Russian oil and gas exports are declining, and Moscow’s revenue from energy sales has fallen from a high of well over $1 billion per day in March.
However, revenues exceeded the cost of the Ukraine war during the first 100 days, with the CREA estimating that Russia is spending $876 million per day on the invasion.
The EU intends to prohibit Russian oil imports arriving by sea by the end of 2022, reducing imports by two-thirds.
In March, the EU also committed to reducing Russian gas imports by two-thirds within a year.
However, it has so far been unable to reach an agreement on an outright ban.
Meanwhile, the United States has declared a complete ban on Russian imports of oil, gas, and coal. Russian oil imports will be phased out by the end of the year in the United Kingdom.
According to the CREA report, the EU’s planned oil embargo will have a significant impact.