European Union leaders enter a crucial stretch this week to make sure runaway energy prices and short supplies do not further tank their struggling economies and foment unrest.
A Bloomberg News/NPR investigation found large U.S. coal companies used bankruptcy and asset transfers to move old mines to shaky new owners, putting at risk federally mandated land reclamation.
San Diego has an ambitious plan to store renewable energy, using extra solar power to pump water up a mountain. This old-style "water battery" technology could be set for a revival.
After a decade of negotiations, this week's agreement resolves questions of who gets to drill for natural gas in disputed waters off the Mediterranean coast. But its implementation isn't a sure thing.
Beneath the streets of hundreds of North America's oldest cities lies a network of pipes delivering steam heat to office buildings and hospitals. These steam loops could be a clean energy solution.