EXPLAINER: What's next for Europe's natural gas during war?

Russian President Vladimir Putin is demanding payment in rubles for natural gas — or else. Germany is talking about gas rationing in case of a cutoff. Prices for the fuel used to heat homes, generate electricity and power industry are through the roof.

There's a lot of discussion around natural gas in Europe against the background of Russia's invasion of Ukraine, to say the least.

Here are key things to know:

WHAT IS PUTIN PROPOSING?

Putin has said importers of Russian gas must now pay in rubles. European leaders said no dice — the contracts say euros or dollars and one side can't abruptly change that.

Changing currency would normally follow extended negotiations, analysts say, with customers demanding something in return for being exposed to fluctuations that would come with paying in the less-stable ruble.

The open questions about what the change could mean have sent shudders through energy markets, raising uncertainty about whether Europe's natural gas could be cut off and cause a major hit to the economy. But Russia also relies on oil and sales to fund its government as sanctions have squeezed its financial system.

The Kremlin offered what could be seen as a loophole. Importers would simply have to establish an account in dollars or euros at a designated bank, then a second account in rubles. The importer would pay the gas bill in euros or dollars and direct the bank to exchange the money for rubles.

In any case, Kremlin spokesman Dmitry Peskov said Friday that the change won't happen immediately: “Payments on shipments in progress right now must be made not this very day, but somewhere in late April, or even early May.”

European leaders have rejected the proposal as “blackmail” and say payments will continue in dollars and euros.

German officials wouldn't...