Russia and Ukraine have agreed to cease fighting in the Black Sea in a U.S.-brokered deal, but it remains unclear whether the agreement can come into force soon — if at all.

Russia had a major caveat: it would abide by the deal only after various restrictions were removed from its agricultural exports. The penalties were imposed by the United States and the European Union, and removing them would be an arduous process.

Kyiv and Moscow also appear to have different interpretations of the agreement announced on Tuesday. Russia framed it as a way to revive a 2022 U.N.-backed deal giving it some control over commercial shipping through the sea. Kyiv, however, insisted that it would not allow the Russian Navy back into the western Black Sea, which Ukraine uses at its main seaborne export route.

Underscoring the mistrust between the two countries, each side accused the other of breaching the truce on Wednesday. Ukraine reported an attack on its port city of Mykolaiv, while Moscow said it shot down two Ukrainian drones over the Black Sea.

Russia’s conditions highlighted how it is in no hurry to end the war. With a sympathetic administration in the White House and as its forces have the upper hand on the battlefield, Moscow has been determined to get as many concessions as possible.

What were Russia’s terms?

The Kremlin said it would not agree to a maritime cease-fire deal unless its state agriculture bank and other financial institutions involved in the trade of food and fertilizers were reconnected to the international payment system known as Swift.

The system has its headquarters in Belgium, meaning that the United States would need to press European regulators to agree. In a statement about the deal, the White House pledged that it would “help restore Russia’s access to the world market for agricultural and fertilizer exports.”

Moscow said it also wanted Western companies to restore deliveries of agricultural equipment to Russia and sanctions removed against its companies, ships and insurers involved in the food and fertilizer trade.

Russia says its exports of grain and fertilizers reached $45 billion in 2023. Even during the war, Russia has been exporting record-high volumes of grain and fertilizers, said Andrei Sizov, director of SovEcon, a Russian consultancy.

If sanctions were lifted against a Russian state bank, the Kremlin could use it for other transactions, too, said Aleksandr Kolyandr, a Russia analyst at the Center for European Policy Analysis.

“The minute you have a sanctions-free bank, you can use it for whatever you want,” Mr. Kolyandr said. “It can be an instrument to crack the sanctions regime,” he said, but “it is much easier to monitor just one bank.”

What is Ukraine’s position?

While Kyiv said it would comply with the maritime cease-fire, it remains skeptical about Moscow’s intentions.

President Volodymyr Zelensky of Ukraine said on Tuesday that Russia’s demand for lifting sanctions showed that “they are already trying to distort agreements.”

Mr. Zelensky also said the U.S. commitment to help bolster Russian agricultural exports was “a weakening of positions and a weakening of sanctions.”

Given Russia’s demands and the differing interpretations both sides have of the deal, it remains unclear what Ukraine stand to gain. Experts note the White House did not say whether the deal would protect Ukrainian ports from Russian attacks and enable the reopening of the ports of Mykolaiv and Kherson — two demands that Ukraine had pushed for during negotiations.

Kyiv also has little interest in returning to the 2022 U.N.-backed agreement that Russia wants to revive. The deal allowed Ukraine to export its grain through an agreed upon Black Sea corridor, and Russia to inspect all commercial ships to ensure that they did not carry weapons.

But Andrii Klymenko, the head of the Black Sea Institute of Strategic Studies, said the inspections delayed exports so much that it made the route unprofitable.

After Russia backed out of the deal, Ukraine secured its own shipping corridor by pushing the Russian Navy out of the western parts of the Black Sea. That allowed seaborne grain exports to return to near-prewar levels.

What may happen next?

Last week, President Vladimir V. Putin of Russia agreed to halt attacks against Ukrainian energy infrastructure for 30 days. Ukraine, which has been in favor of a full immediate cease-fire, followed suit. Both countries reaffirmed on Tuesday their commitment to institute a 30-day moratorium on energy strikes.

On Tuesday, the Kremlin published a list of facilities that fall under the moratorium. The list includes oil refineries, pipelines and storage facilities, nuclear plants, hydroelectric dams and energy transmission infrastructure.

But both sides have traded accusations of attacks against each other’s power grid over the past week, and it was unclear whether they could find common ground soon. The situation with the energy cease-fire highlighted how Moscow has been willing to drag the talks, portraying itself as open to negotiations but making no major concessions.

Rustem Umerov, Ukraine’s defense minister, said on Tuesday that “additional technical consultations” would have to be held as soon as possible to effectively carry out the energy and maritime agreements.

A gleaming new data center sits less than half a mile from the electric substation where a fire plunged Heathrow Airport into darkness last week. The data center’s own power was also cut that day. But no one who relied on it would have noticed, thanks to a bank of batteries and backup generators designed to kick in instantly.

Meanwhile it took officials at Europe’s busiest airport close to 18 hours to bring its terminals and runways back into operation, causing global travel delays and underscoring the vulnerability of Britain’s infrastructure.

It is a striking contrast that energy experts say can be explained largely by one word: Money.

“The data center industry is relatively young. They are more attuned to the cost of a catastrophic failure,” said Simon Gallagher, the managing director at UK Networks Services, which advises clients on the resilience of their electricity networks. He said most of the world’s airports — including Heathrow — have not been willing to make the big investments necessary to build total backup systems.

Even at an airport the size of Heathrow, which officials have described as equivalent in power use to a small city, it is possible to create backup systems robust enough to maintain normal operations during a catastrophic power failure, Mr. Gallagher and other engineering experts said.

But it could cost as much as $100 million and would likely take years to put in place. So far, most airports have chosen not to make the investment.

“It comes down to a cost-benefit analysis,” Mr. Gallagher said. “At the minute, there seems to be an assumption that it would cost too much.”

The Airport

Heathrow officials were quick to point out after Friday’s incident that the airport has backup power in place for its most critical systems: runway lights and the tower’s traffic control safety systems. If a plane had needed to land that day, it could have done so safely.

But the airport had no way to power the rest of the sprawling and complicated facility: the vast terminals, filled with shops and restaurants, moving walkways and escalators. Cut from the grid, there was no power to move bags to the claim area, or for ticket counters or bathrooms.

First opened at the end of World War II, Heathrow has been expanded and updated over the decades. The result has been a patchwork of older and newer electrical cables and systems carrying an ever-increasing demand for power.

“The grid is old,” said Najmedin Meshkati, an engineering professor at the University of Southern California. “For aviation, for the grid and for other safety critical systems, the older that they get the more important maintenance becomes.”

What Heathrow does not have are backup generators that could supply the 40 megawatts of power required at peak times to maintain normal operations.

Instead, on Friday, engineers at the airport had to manually reconfigure switches at another substation to temporarily reroute available power to Heathrow. That took hours, and because the airport’s systems had been sitting without power, it took even more time to boot them back up, followed by rounds of testing.

The Substation

The airport’s primary power source is the Hyde North substation about a mile away, owned and operated by National Grid Electricity Distribution, the private power company responsible for the area.

Two of the substation’s transformers were taken offline by the fire. The cause is still under investigation, but the police said Tuesday they had found “no evidence” of suspicious activity.

John Pettigrew, the chief executive of National Grid, told The Financial Times that there was “no lack of capacity” in the area after the fire. Energy experts said that is correct: The places where there is an actual lack of power tend to be developing countries and war zones.

The challenge, though, was making use of the area’s ample power once Heathrow’s connection to Hyde North was severed. Thomas Woldbye, the chief executive of the airport, told the BBC that he was proud of the employees who worked through Friday to switch their systems to use power from two nearby substations.

But he said that Heathrow would now assess whether to install “a different level of resilience if we cannot trust that the grid around us is working the way it should.” Heathrow did not respond to requests for comment for this story.

The Data Center

The airport’s leaders might want to examine their corporate neighbor just to the north.

The Union Park data facility, run by Ark Data Centres, is a six minute walk from the Hyde North substation. Inside, computers run 24 hours a day, powering the cloud services and artificial intelligence that are at the heart of modern banking, commerce, research and government operations.

Huw Owen, the company’s chief executive, said its electrical supply was interrupted when the fire broke out. But sophisticated sensors detected the loss of power and instantly shifted to batteries that operate much like an uninterruptible power supply system for a personal computer. That gave the facility’s generators time to spin up, and they soon took over.

“It’s a well-rehearsed, well-known process,” Mr. Owen said in an interview. “It’s this mind-set that resilience and keeping everything powered is absolutely front and center of our world.” Mr. Owen said the company installed the costly generator backup system despite expectations it might never be needed. A permitting application prepared for the company in December described the possibility of a power outage as “extremely rare.”

“It would require a catastrophic regional failure on the grid, or at the supplying power station, and would likely impact not only the site but the surrounding London area,” the summary notes. “As a result, the grid connection is considered to be highly reliable as demonstrated in the grid reliability letter provided with the application (calculated as 99.999605%).”

The Decision

Prime Minister Keir Starmer told the BBC after the fire, “I don’t want to see an airport as important as Heathrow going down in the way it did on Friday.”

But how to avoid it in future?

The challenge in making electrical upgrades to places like Heathrow is determining how to pay for it when high energy costs are straining consumer budgets. In the past, airport investment has often been passed on to customers in the form of higher ticket prices on airlines.

Mr. Gallagher, the consultant on electrical network resilience, noted that new airports in places like Dubai were built with the kind of backups that could keep terminals open. And a few older airports, like Schiphol in Amsterdam, have upgraded their facilities with large generators.

But if Heathrow’s management wants to follow suit, experts say, they will need to accept that it requires a large investment to prevent a crisis that may not happen again for many years.

“It’s a hell of a lot easier to build it from Day 1 than it is to try and retrofit stuff,” Mr. Owen said of Heathrow and other old airports. “They are as capable of instigating resilience at those sites as I am, but they’re now going to have to retrofit, whereas I built it from Day 1.”

European leaders have gotten the message from Washington about doing more for their own defense and for Ukraine, too. They are talking tough when it comes to supporting Ukraine and about protecting their own borders, and they are standing up to a demanding and even hostile Trump administration.

But there is an inevitable gap between talk and action, and unity is fracturing already, especially when it comes to spending and borrowing money in a period of low growth and high debt.

The Dutch and others are not fans of raising collective debt for defense. Keeping Hungary on board is ever more difficult.

And when the president of the European Commission, Ursula von der Leyen, announced a plan for billions more for the military, called “ReArm Europe,” two of the bloc’s largest countries, Italy and Spain, thought that was all a bit aggressive. So now the plan has been rebranded as “Readiness 2030.”

That’s a year after Donald J. Trump is no longer expected to be president. But it is also a realistic understanding that Europe’s new commitment to self-reliance will take time, billions of euros, political deftness and cooperation with the United States.

Kaja Kallas, the former prime minister of Estonia who is now the chief foreign and security official for the European Union, has been a forceful advocate for supporting Ukraine as a first line of European defense against an aggressive, militarized Russia.

But it has been a rocky start for Ms. Kallas. Her effort to get the E.U. to provide up to 40 billion euros (more than $43 billion) to Ukraine through a small, fixed percentage levy on each country’s national income has gone nowhere.

Her backup proposal, for an added €5 billion as a first step toward providing Ukraine two million artillery shells this year, was also rejected by Italy, Slovakia and even France, an E.U. official said, speaking anonymously in accordance with diplomatic practice. The countries insisted that contributions to Ukraine remain voluntary, bilateral and not required by Brussels.

And her recent response to Mr. Trump’s effort to push Ukraine into a cease-fire without security assurances rubbed many the wrong way, both in Europe and Washington, as dangerously premature. “The free world needs a new leader,” she wrote on X. “It’s up to us, Europeans, to take this challenge.”

But in fact the Europeans are working hard to respond to Mr. Trump in a convincing fashion. Ms. von der Leyen sold her rearmament or readiness plan with a headline figure of €800 billion. But only €150 billion of that is real money, available as long-term loans for countries that wish to use it for the military. The rest simply represents a notional figure — a four-year permission from the bloc for countries to borrow even more for military purposes out of their own national budgets.

For a country like Germany, which has low debt, that is likely to work, especially now that the next chancellor, Friedrich Merz, got Parliament to agree to loosen its own debt rules to allow for huge spending on the military, civilian infrastructure and climate.

But for countries like Italy and Spain, which can feel far away from Russia and have their own fiscal problems, that may not be an easy choice. France, despite President Emmanuel Macron’s strong words about European “strategic autonomy” and his desire to lead the Continent, is itself deeply indebted, and piling on more debt is politically and economically hazardous.

France, too, is insisting on a high percentage of European content and manufacture for any weapons bought with the new loans, and is so far working to keep American, British and Canadian companies from participating. And other issues are intruding; an E.U. effort to draft a defense agreement with Britain is being held up by Paris over squabbles about fisheries.

But Europe will spend considerably more on defense, as it has known it must, said Ian Lesser, director of the Brussels office of the German Marshall Fund. “The advent of the Trump administration has given history a shove,” he said. “We’re not in a linear environment, with a linear spending trajectory.”

On NATO, too, major European countries are beginning to talk seriously about how to replace the vital American role in the alliance — both in terms of sophisticated arms and political and military leadership. But there is little desire to accelerate any rupture with Washington, since any such transition is likely to take five or even 10 years.

Now, 23 of 27 E.U. states are also NATO members, including about 95 percent of E.U. citizens, and NATO has its own requirements for new military spending. European states are discussing what they can propose to Mr. Trump at the next NATO summit in June, in The Hague, that will ensure American cooperation in any transition.

But while Trump officials have privately reassured Europeans that the U.S. president supports NATO, will retain the American nuclear umbrella over Europe and remains committed to collective defense, Mr. Trump’s views are famously changeable, and he persists in viewing NATO as a club where members pay for American protection.

In his first term, he often mused about leaving NATO while saying the United States will defend only countries that pay enough for defense. This month, he repeated that warning. He has demanded that NATO members pay up to 5 percent of gross domestic product on defense, significantly more than the United States, which spends about 3.4 percent of G.D.P. on its global military.

NATO officials want to set a new spending goal at the summit in June, but one closer to 3.5 percent of G.D.P., up from 2 percent now.

Reinforcing concerns in Europe that the United States may no longer be a reliable partner was the extraordinary discussion among top Trump administration officials of the American strike on Yemen, revealed by Jeffrey Goldberg in The Atlantic, who was inadvertently added to the group chat on the messaging app Signal.

The discussion was replete with comments like this one from Vice President JD Vance: “I just hate bailing out the Europeans again.” And there were boastful messages about finding a way to get Europe to pay for the operation — but nothing about China, which benefits hugely from the trade passing through the straits near Yemen, including much of its oil imports and its exports to Europe.

Mr. Trump’s sudden suggestion last week that a future American fighter plane might be sold to allies in a downgraded version has also reinforced these concerns.

Prompted by Mr. Trump’s stated intention to leave Ukraine’s defense to Europe, Britain and France are working on a proposal for a European “reassurance force” to be on the ground in Ukraine once a peace settlement is reached between Kyiv and Moscow, if one ever is. But so far, no other E.U. country has publicly volunteered to serve in such a force, which is largely undefined and unfinanced, and which Russia has consistently rejected.

Mr. Macron is to meet with President Volodymyr Zelensky of Ukraine on Wednesday night. Then on Thursday, he is scheduled to be host at another meeting of this “coalition of the willing,” guest list unclear. But Mr. Trump’s special envoy, Steve Witkoff, called the idea “simplistic” and “a posture and a pose.”

Efforts at creating a cease-fire between Russia and Ukraine continued, with the announcement on Tuesday that the two countries had agreed to stop attacks on ships in the Black Sea. But even that agreement was subject to a Russian demand that Western countries drop restrictions on Russian agricultural exports.

Ms. von der Leyen talks of making Ukraine “a steel porcupine,” too difficult for Russia to swallow in the future, an echo of an early plan for Ukrainian defense drafted by a former NATO secretary general, Anders Rasmussen.

But even a steel porcupine is not a security guarantee, and it implies an endless commitment to supporting Ukraine.

Prime Minister Bart De Wever of Belgium summed up the European problem nicely last week. He praised Mr. Macron for drumming up a “coalition of the willing” to boost military aid for Ukraine as U.S. support dwindles. But he said he had pleaded for a bit more structure in the group.

“We are willing — but willing to do what, exactly?” he asked.

“Making It Work” is a series about small-business owners striving to endure hard times.

Bird flu outbreaks that wiped out about 15 percent of the nation’s egg-laying chickens and drove wholesale egg prices to a peak of more than $8.50 a dozen in February have vexed grocery shoppers and prompted big breakfast chains to add surcharges to diners’ checks. But for owners of small eateries, paying double or triple for an ingredient they crack by the hundreds each day could potentially put them out of business.

These business owners are getting creative: changing recipes; using liquid or powdered eggs, which haven’t gotten as expensive as quickly; and selling whatever items they can that don’t include eggs — things like falafel or packaged snacks or even fresh flowers.

Prices have come down in recent weeks but remain historically high, and worry about new outbreaks is keeping business owners on edge. The U.S. Department of Agriculture predicted on Tuesday that egg prices would climb nearly 58 percent this year. Food trends like all-day breakfast menus and protein-heavy diets are keeping demand — and therefore prices — high, according to analysts at CoBank, a bank that lends to farmers.

Eggs are too perishable to be stockpiled and small businesses generally don’t have extra cash for refrigerator space to keep extra eggs even for brief periods, said Rob Handfield, a professor and the director of the Supply Chain Resource Cooperative at North Carolina State University.

“It’s not like you can stock up on a month’s worth of eggs,” he said. “You really rely on those weekly or daily deliveries of eggs if you’re a small business.”

Restaurant and bakery owners could charge more for their baked goods or breakfast sandwiches, but they fear that hiking prices will drive away customers.

“That’s the big challenge for a lot of owners right now,” said Holly Wade, executive director of the NFIB Research Center at the National Federation of Independent Business.

Here’s how the owners of four small businesses are trying to be creative in adapting to the jump in egg prices.

For most of the 24 years Ted Karounos and his wife, Ann, have owned the Square Diner in the TriBeCa neighborhood of New York City, egg prices hovered between $30 and $35 for a case of 30 dozen eggs. During the pandemic, prices spiked as high as $100 a case.

Today, Mr. Karounos would be thrilled with that price. “This year’s been scary,” he said. “I’ve never seen $200 before.” Now, he is paying $239 per case — a nonnegotiable cost, considering that he serves about 360 eggs a day at the Square Diner, a classic restaurant with booths, a long row of counter stools and vintage signs adorning the walls.

Eggs are the star of the diner’s signature omelets and of the “lumberjack” breakfast platter that includes eggs and pancakes, which also incorporate eggs in the batter. In total, Mr. Karounos estimated that about 60 percent of his menu included eggs.

Mr. Karounos raised prices 7.5 percent last year to keep pace with inflation, he said, and is considering hiking them again. The margins on something as workaday as a two-egg breakfast have shrunk drastically, he said: “You’re talking about a dollar per plate of lost profit.”

“This is not an ingredient we can go without,” he added. “Right now we’re just absorbing the hit.”

Oh My Cupcakes!, Sioux Falls, S. D.

At least 90 percent of everything Melissa Johnson sells includes eggs. That’s not unexpected for a bakery, but Ms. Johnson, founder and chief executive of Oh My Cupcakes! in Sioux Falls, S.D., said the price of eggs led her to add other types of inventory.

“The more items we can come up with that don’t include eggs but still supplement our income, the better off we’ll be,” she said. She has added bags of snack mix and dry pancake batter mix to the shelves, along with gift items like candles and fresh flowers.

Ms. Johnson considered adding a surcharge to offset some of the increase in egg costs. But she worried that even an increase as low as 25 cents would dissuade customers, who are already spending less now than they did in previous years.

“We could easily price ourselves out of the market,” she said. “Cupcakes are not a necessity. We understand people are really needing to make some decisions with how they’re spending their hard-earned money.”

The sweet breads, cakes and desserts Mark Burgos sells at his family-owned bakery in the Pico-Union neighborhood of Central Los Angeles have two things in common: traditional Mexican flavors and lots of eggs.

“Very few things don’t have eggs in them,” he said, listing customer favorites like kings cake, a traditional holiday sweet bread; tres leches cake; and flan. His flan recipe alone, which makes two dozen portions, takes 260 eggs. “You don’t have a lot of wiggle room,” he said.

Mr. Burgos has started buying fewer eggs and hunting down liquid and powdered eggs so he can save whole eggs for recipes where he can’t make substitutions. “We’ve had to use everything we could get our hands on,” he said, adding that he found liquid eggs in January but had no such luck in February.

Mr. Burgos said he had had to raise prices by about 20 percent, but he said the increase — plus the economic impact of the recent wildfires in Los Angeles — had hurt business. “Since things are expensive, things slow down,” he said. “Everybody’s having a hard time.”

Side Piece Kitchen, Tacoma, Wash.

Eggs are ubiquitous on the menu at Side Piece Kitchen, a restaurant in Tacoma, Wash., that specializes in brunch: The sandwiches are laden with poached or fried eggs as well as egg-based sauces. Even the latkes — the restaurant’s version of breakfast potatoes — use eggs as a binding ingredient.

But the owner, Hailey Hernandez, who opened the restaurant with her mother and husband in 2022, says her newest menu items have fewer eggs — or none at all. Recently, the cost of eggs prompted her to halve the number of fried eggs in her signature maple-sausage-and-cheddar biscuit sandwich down to one, and to set a daily market price for eggs ordered on the side ($6.50 for two eggs in mid-March).

Side Piece’s weekly specials no longer feature eggs, Ms. Hernandez said. “We’re spending more time really transforming ingredients” to elevate cheap items like chickpeas into an appetizing dish, she said. “This week we made falafel from scratch.”