"President Obama came to Las Vegas Monday to throw his weight behind the booming solar energy industry in its recent political struggles, and to announce a bevy of initiatives to promote clean-energy growth in America’s homes and on its rooftops. It was the first stop in a climate and energy-focused tour that will also take the president to New Orleans and Arctic Alaska this month."

"On a remote Utah ridge covered in sagebrush, pines and wild grasses, a Canadian company is about to embark on something never before done commercially in the United States: digging sticky, black, tar-soaked sand from the ground and extracting the petroleum."

"President Barack Obama and Nevada's U.S. Sen. Harry Reid, two of the most powerful Democrats in the nation, are playing key roles in the National Clean Energy Summit in Las Vegas on Monday."

"Scientists may have been overestimating China’s emissions of carbon dioxide, the main greenhouse gas driving global warming, by more than 10 percent, because of inaccurate assumptions about the country’s coal-burning, according to a study published on Wednesday."

"Recently released testing results in western Pennsylvania, upstream from Pittsburgh, reveal evidence of radioactive contamination in water flowing from an abandoned mine. Experts say that the radioactive materials may have come from illegal dumping of shale fracking wastewater."

"The 585 earthquakes that Oklahoma had in 2014 was a lot. But this year, Oklahoma has had more than that in less than nine months."

"HOUSTON — With oil prices collapsing and companies in retrenchment, a federal auction in the Gulf of Mexico on Wednesday attracted the lowest interest from producers since 1986."

"The U.S. Environmental Protection Agency on Tuesday proposed new standards to cut greenhouse gas emissions and volatile organic compounds from oil and gas facilities, a key part of a broader strategy to cut methane emissions in the sector by 40 to 45 percent below 2012 levels in the next ten years."

"Democratic presidential candidate Hillary Clinton on Tuesday staked out her opposition to Arctic oil exploration, putting her at odds with the Obama administration one day after it approved drilling off Alaska."

"The impact of low oil prices could have long-term consequences for drilling companies. But hydraulic fracturing technology could allow the industry bounce back more quickly, experts say."