It was the kind of week that reminds you energy is never just one story. Traders spent it glued to headlines out of the Middle East, where a shaky ceasefire wobbled and oil lurched with it. Washington, meanwhile, was busy writing checks for coal and celebrating a nuclear milestone four decades in the making. Here is what mattered, why it mattered, and what to watch next.

Oil markets ride another wave of war and peace

Crude has been the market’s mood ring all year, and this week it flashed every color. WTI leapt more than 4% to above $94 a barrel on Monday after Iran and Israel exchanged missile strikes for the first time since their April ceasefire, rattling hopes that President Trump could land a fresh 60-day truce with Tehran. By later in the session the panic had cooled: Iran said it had ended its military operations against Israel, Washington reported progress on talks, and Brent settled back near $94 while WTI eased toward $91.

To understand why a single exchange of fire moves prices this much, rewind to late February, when the conflict erupted and the Strait of Hormuz — the chokepoint for roughly a fifth of the world’s seaborne oil — went effectively dark. Brent spiked to about $138 a barrel on April 7 and averaged $117 for the month, according to the U.S. Energy Information Administration. Prices have drifted down since, but the war premium never fully left the building.

The supply side offered its own drama. OPEC+ — now down to seven core members after the United Arab Emirates formally exited at the start of May — approved another modest July output increase of 188,000 barrels per day. It was the group’s second straight hike of that size and its fourth since Hormuz closed, a largely symbolic gesture given how little spare capacity is reachable while Gulf shipping stays snarled. The next OPEC+ meeting is set for July 5.

On the demand side, China kept its foot off the gas. The world’s biggest crude importer has been leaning on its own stockpiles rather than buying abroad since the conflict began, and fresh data this week showed another aggressive pullback — a quiet but real cushion against higher prices.

One date worth circling: the EIA’s monthly Short-Term Energy Outlook was due for release this week, and it should give the first official read on how the agency now sees prices unwinding as Gulf barrels — eventually — come back.

Washington opens the spending taps for coal

While markets fixated on the Gulf, the Trump administration spent the week making the case that America’s energy future runs partly on its past. On June 4, the Department of Energy said it would put up to $500 million in Defense Production Act Title III funds behind the coal industry: roughly $425 million spread across a dozen projects to extend and modernize the existing fleet, plus $75 million for the West Gateway Terminal in Oakland, California — a rail-served marine export hub designed to ship more than 10 million tons of bulk commodities a year to allies including Japan, South Korea, Taiwan, Vietnam and Malaysia.

A separate announcement steered another $350 million toward four projects to build, restart and modernize coal plants. The DOE framed the whole push around grid reliability and “baseload” power — the always-on generation that keeps the lights on regardless of weather — and tied it explicitly to surging electricity demand from AI data centers and a manufacturing rebound.

Stack it all together and the numbers get big. In its “Beautiful, Clean Coal” fact sheet, the department said it has now saved or supported 45 coal plants and more than 40 gigawatts of capacity, avoiding roughly $50 billion in costs to build new generation and leveraging about $1.7 billion in private investment. The action builds on Presidential Determinations Trump signed in April under Section 303 of the Defense Production Act, which designated coal supply chains as essential to national defense.

The administration also kept a Florida coal plant running under an emergency order, citing blackout risk. Not everyone is convinced. Critics, including analysts quoted by Latitude Media, argue the government is spending taxpayer dollars to subsidize power the AI industry could pay for itself, and have questioned repurposing carbon-capture funds to keep aging coal units alive. Expect that debate to sharpen as more projects are named.

A reactor goes critical for the first time in 40 years

The week’s most quietly historic moment happened in the Idaho desert. On June 4, Antares Nuclear’s Mark-0 microreactor achieved initial criticality at Idaho National Laboratory — meaning engineers coaxed it into a self-sustaining nuclear chain reaction at minimal power. It is the first privately developed, non-light-water reactor to go critical in the United States in more than four decades, and the 53rd reactor built at the storied Idaho site since 1951.

The Mark-0 is a sodium heat-pipe-cooled microreactor running on HALEU TRISO fuel — the pebble-like, high-assay low-enriched uranium that has become the building block of America’s advanced-reactor ambitions. Antares pulled it off as the first company to clear the DOE’s Reactor Pilot Program, a fast-track effort launched under a May 2025 executive order that challenged industry to bring at least three advanced reactors to criticality by July 4, 2026. The work was done with Idaho National Laboratory, BWX Technologies and observation support from the U.S. Army.

“By bringing the first American non-light-water privately developed reactor to criticality in more than four decades, Antares has shown what is possible.”

— Chris Wright, U.S. Energy Secretary

Criticality is a long way from a working power plant — Antares is targeting actual electricity generation in 2027 and a microreactor at a military installation by 2028 — but it validates the design and, just as importantly, the regulatory shortcut. It wasn’t the only nuclear news, either: the same day, the U.S. and Japan announced a $1 billion research partnership under the administration’s Genesis Mission, with Japan as the first international partner, and the DOE’s newer Nuclear Energy Launch Pad continued lining up developers behind the pilot cohort.

What to watch next week

• Whether the latest Iran-Israel ceasefire holds — and any signal that the Strait of Hormuz could reopen to commercial traffic, the single biggest lever on oil prices right now.
• The EIA’s fresh Short-Term Energy Outlook for its updated price path now that a partial supply recovery is in view.
• The July 4 deadline for the Reactor Pilot Program: can two more advanced reactors join Mark-0 in reaching criticality?
• More named coal projects under the Defense Production Act, and the political fight over who ultimately pays.
• The next OPEC+ meeting on July 5, where the group will weigh another incremental output move.