Most European countries say they are determined to switch their energy supplies, but it’s not as easy as it is in, say, the U.S.

Russia has long dominated Europe’s energy market, supplying the continent with 40% of its natural gas and 25% of its oil. This week, EU leaders unveiled a plan for the continent to begin progressively phasing out Russian oil imports before the end of the year. 

Europe is already scouring the globe for new supply lines for gas, oil and diesel fuel, signing off on new trade deals in the Americas, Africa, the Middle East, and India, as well as an increased focus on local energy production. But gearing up for a winter with fewer Russian energy imports is still a tall order.

“It’s massively, massively uncertain,” Alan Gelder, vice president of oil markets research at global energy consultancy firm Wood Mackenzie, told Fortune. “A lot of Europeans are very concerned about security of supply, but feel that they need to try to ban imports of Russian energy, which makes the situation very volatile, very uncertain, and very complex.”

The continent will have to navigate new trade partners, and likely have to deal with a prolonged period of higher energy prices. Here’s how it’s working to replace its oil, diesel and gas supplies.

Where Europe can get its oil

Before the Russian ban kicks in, Europe will have to round out its oil reserves, and it has already started to do so by turning to Middle Eastern refiners. 

French oil and gas company TotalEnergies started importing crude from Abu Dhabi this month, the first such shipment since 2020, with more European oil companies expected to sign off on deals with refiners from the Emirates over the coming months.

Atlantic producers are also expected to play a key role in weaning Europe off Russian oil, and shipments have already begun. Oil imports to Europe from major Atlantic refiners in the U.S., Brazil, and West Africa have already grown by 17% in the first quarter of 2022, according to industry analysts from International Seaways, a petrochemical shipping company.

Ironically, Europe cutting off Russian oil supply would mean that Russia will likely reroute its trade flows to friendlier markets. With these countries buying more Russian oil and less from traditional suppliers in the Middle East, it could actually increase supply to Europe from producers that have so far been relatively unused.

“Even if the EU bans the use of [Russian] fuels, those fuels are still able to be sold, and they’re likely to go to the deficit markets in Latin America and Africa,” Gelder said. “That would enable U.S. Gulf Coast and Middle East refiners to divert the exports typically made towards those regions towards Europe.”

If Europe can nail down deals with Middle Eastern and Atlantic refiners, it stands a good chance of keeping its oil reserves at a healthy level before the Russian ban takes full effect by the end of 2022. Global oil flows are shifting rapidly, as countries such as India explore buying more Russian oil, and European companies will need to pick out which global suppliers might be open to signing new deals now that these trade lines are being rewritten

Where Europe can get its diesel

Although the continent has been highly reliant on Russia for the fuel since the early 2000s, when diesel was the fuel of choice for most European drivers. The EU has been suffering from diesel price hikes since the invasion began.

“It is an immediate concern, and one that’s actually been the least discussed,” Gelder said on the topic of diesel trade flows to Europe. 

Russian diesel supplies have largely been flowing into Europe uninterrupted for the duration of the war, according to Gelder, and a cutoff of flows would hurt some countries more than others. Germany, for instance, relies on Russia for 74% of its diesel imports.

Russia’s supply of diesel might be even harder for Europe to replace than oil, but the continent does have some options. The U.S. and the Middle East are strong diesel producers, and suppliers in both countries have already ramped up their diesel shipments to Europe this year. 

Another option is India, a large diesel producer that has been shipping the fuel to Europe since March, with increased trade flows expected over the coming months.

Where Europe can get its gas

European leaders are actively discussing how to increase trade flows of liquefied natural gas (LNG) from outside of Russia. LNG is a frozen form of gas that can be stored and transported on ships, without the need to construct a new pipeline.

But while producers in the Middle East and the U.S. could conceivably increase their LNG shipments to Europe significantly, infrastructure remains a major hurdle.

Importing LNG requires specialized import terminals that can regasify the liquid, but these terminals are currently few and far between in Europe, especially in countries that would need the gas most.

“A lot of Europe’s regasification capacity is concentrated in the United Kingdom and Spain—both of which have only limited interconnector capacities to ship gas to the rest of Europe,” Leon Izbicki, a natural gas analyst at Energy Aspects, a London-based energy research and consultancy firm, told Fortune.

“This limitation is already triggering large-scale investments in new infrastructure,” Izbicki said, but added that these new investments will take time, and that “infrastructure bottlenecks limit Europe’s ability to replace further volumes of Russian gas in the short-term.”

Ramping up LNG infrastructure might be a long-term solution for Europe’s energy woes, but the continent will have to resort to different mechanisms to ensure short-term gas security, including focusing on local production.

Increasing natural gas trade flows with nearby energy-rich countries like Norway has already proven effective in easing prices, and increased flows should provide some relief for continental Europe next winter. 

While Europe tries to ramp up its investments in natural gas infrastructure long term, European gas producers such as Norway have advocated for more domestic extraction, which could help bridge the supply gap.

Some European countries have pushed for a faster transition towards renewable energy, but doing so would be “complicated,” according to Olivia Lazard, a researcher with the European branch of the Carnegie Endowment for International Peace whose work focuses on climate change, geopolitics, and energy.

“There is obviously an intention to move [towards renewables] because it’s in line with Europe’s climate pact and its 2030 emissions deadline,” Lazard said, but added that supply chain constraints of rare Earth metals and other materials critical to renewable energy infrastructure make this a less-than viable short-term option.

A faster transition towards renewables may be in the cards for Europe in the long term, but it probably won’t do much to help the continent build its energy reserves this year.