This is part of the America's Future series airing on FOX News Channel, looking at the challenges facing the country in the 21st century.

BERLIN — High-cost energy supplies and Europe's dependence on Russian fuel have some observers wary of a new Cold War between Russia and the West, being fought once again on German soil.

In Berlin and elsewhere there are many reminders of Russia’s energy clout, with huge electric plants using Russian natural gas to power German homes and factories.

“The bear is back. Not with nuclear missiles and tanks, but with gas and cash,” said Edward Lucas, author of “The New Cold War: Putin's Russia and the Threat to the West.”

Germany gets 40 percent of its natural gas from Russia, though German government officials say they’re not overly worried about their dependence on Russian gas.

“It’s never ideal to rely on one source, but we don’t really have much concern for Russia,” said Hartmut Schneider, deputy director general of Germany’s Ministry of Economics.

But Russian Prime Minister Vladimir Putin says energy policy is integral to Russian diplomacy, and other Russian energy clients, like Ukraine and Belarus, had their supplies cut off in recent years following political squabbles.

While Russia hasn’t made a direct a move on Germany, critics say Moscow could still be influencing German policy — to the detriment of the U.S. — on matters like NATO and EU expansion in the former Eastern Bloc, as well as the installation of missile sites there.

“Russia has discovered that oil and gas are central instruments to raise its political ambitions on the world stage,” said Alexander Rahr, director of the Russia/Eurasia program at the Berlin-based German Council on Foreign Relations.

A principal tool in Russia’s arsenal is the Kremlin-dominated gas firm Gazprom, which sponsors a German soccer team, has offices in Berlin and stakes in German energy companies — and has many German friends.

Former German Chancellor Gerhard Schroeder was hired to handle a major Gazprom-related pipeline deal shortly after leaving office.

Gazprom spokesman Burkhard Welki, a former Berlin official himself, said these relations are just healthy energy interdependence, but offered a warning for Europeans who want to stand up to Russia.

“If someone wants to keep us out of the European Union, Western Europe, that’s a problem,” he said. “Because to say it very clearly: We have the gas.”

Yet soaring energy prices, which have given Russia much of its new power, may also be its undoing. Even as Russia pressures its former satellites, Europe is looking for alternative fuel sources and alternative energy, which could take the flex out of Russia's energy muscle.

Click here to see more reports on America's Future.

Greg Palkot currently serves as a London-based senior foreign affairs correspondent for Fox News Channel (FNC). He joined the network in 1998 as a correspondent. Follow him on Twitter@GregPalkot.