ATHENS (Reuters) -Global investments in renewable energy aren't bearing fruit and the world should focus on securing reliable supplies of fossil fuels, U.S. energy and interior secretaries said this week as they worked on convincing Europe to buy more U.S. oil and gas.

The U.S. has become Europe's top oil and gas supplier on the back of the U.S. shale boom and its companies are seeking to boost the share as the European Union moves to fully cut off remaining Russian energy imports.

The message from U.S. officials at an energy conference in Athens this week highlights the shift in U.S. policy under the Trump administration, which has rolled back environmental regulations and touted oil and gas "domination" as a central driver for the U.S. economy and international influence. 

"It just hasn't worked," U.S. energy secretary Chris Wright said of the transition to renewable energy at the conference, where U.S. companies announced deals to supply and drill for gas in Europe. 

Wright said on Thursday that he wanted the U.S. to replace "every molecule" of Russian gas that goes into Western Europe.

RENEWABLES HAVEN'T DELIVERED, U.S. SAYS

The U.S. produces over 20 million barrels per day of oil and liquids - every fifth barrel in the world. 

Its message highlights the gap with many nations in the EU, which this week agreed to cut emissions by 90% by 2040, from 1990 levels - although that was watered down from previous aims.

The world has spent between $4 trillion and $8 trillion to connect solar and wind farms to the grid, Wright said, but last year such sources still represented just 2.6% of global energy. 

"We spend more money every year on low carbon energies than we spend on hydrocarbons, but ... the shift in money has not resulted in a shift in energy supply," said Wright, who later described climate change as a "hoax".

Interior Secretary Doug Burgum said: "There is no energy transition, there's only energy addition." 

(Writing by Edward McAllisterEditing by Mark Potter)