Saudi Arabia and its OPEC allies’ firm stand against cutting crude output to slow the plunge in oil prices has set the energy world on a painful course that will leave the weakest behind, from governments to U.S. wildcatters.

Opec threw down the gauntlet to US shale oil producers by deciding not to cut its production, in a move that sent the oil price tumbling by more than 8 per cent to a four-year low.

Oil anchors world financial markets, and Opec has just decided to raise its anchor. The consequences could be profound, and go far beyond the power game between the traditional oil producers in the Middle East and the new generation of shale producers in North America.

Shares in the world’s biggest energy groups have tumbled in a market rout as plunging oil prices put at risk billions of dollars of investment and jeopardised future supplies of crude.

Putin Says Russia Doing Fine in Face of Tumbling Crude Prices

Even as Western sanctions over Ukraine bite, crashing oil prices are hitting Russia's economy and government finances.

Brent and West Texas Intermediate crudes fell to the lowest level in more than four years after OPEC failed to cut its output in response to a glut.

Battered by sanctions and oil’s accelerating price crash, OAO Rosneft (ROSN) has lost 38 percent of its market value this year in dollar terms and today the whole company, TNK-BP and all, is worth $50 billion.

Europe must wean itself off Russian gas and look to places like the Caspian Sea or the Middle East for alternative supplies, as the conflict in Ukraine underscores the importance of energy independence

US Vice-President Joe Biden claimed Russia is using energy as 'a weapon' and urged European countries to diversify sources for the purposes of energy security.