Companies say it’s a better way to dispose of the Cold War-era material — and fix a shortage of nuclear fuel. But the plan has also faced criticism from nonproliferation experts.
While global warming is still a threat, the decision to back away from a worst-case outlook raises questions about whether some risks have been overstated.
The dream of clean hydrogen has tantalized energy experts for years, but producing it has been tough. Many start-ups think the answer could lie beneath our feet.