First developed in the early 19th century, the Stirling engine is regaining favor as a way to squeeze even more power out of the sun's energy.
Major oil companies including Total, Eni, Saudi Aramco, BG, Royal Dutch Shell, and others have come together to form an industry group to weigh in on climate negotiations to take place in Paris later this year.
Researchers have grown increasingly concerned by the threat that global warming poses to global peace. And political leaders are beginning to take notice.
Crude prices have risen over the past few weeks, after collapsing from $100 a barrel last summer to around $50 a barrel early this year. But as James Stafford writes, some predict prices could fall again later this year.
Iraqi oil production is growing, writes Nick Cunningham, even as Islamic State gains ground. The global glut of crude has insulated markets against geopolitical shocks, and the fall of Ramadi hasn't impacted production in Iraq's oil-rich South.
Azerbaijan has long been a key piece in the US's foreign policy puzzle, writes Nick Cunningham, and news that Congressmen traveled there at the expense of a state-owned oil company is the latest link between the countries.