Saudi Arabia's oil minister, Ali Al-Naimi, shown in Kuwait last month, has played down the drop in oil prices. The country continues to pump oil at high levels, saying it wants to preserve its market share. But this has also contributed to a 25 percent drop in oil prices since June. Yasser Al-Zayyat/AFP/Getty Images hide caption

itoggle caption Yasser Al-Zayyat/AFP/Getty Images

A fireball goes up at the site of an oil train derailment in Casselton, N.D., in this Dec. 30 photo. The fiery crash left an ominous cloud over the town and led some residents to evacuate. Bruce Crummy/AP hide caption

itoggle caption Bruce Crummy/AP

A woman in Senegal charges her cellphone using a port in her solar-powered LED lantern. Bruno Déméocq/Courtesy of Lighting Africa hide caption

itoggle caption Bruno Déméocq/Courtesy of Lighting Africa

Guillermo Gomez, husband of Vilma Marenco, holds his daughter in their home in Northeast Houston. Marenco was killed in April after being hit by an uninsured trucker who ran a red light. Mayra Beltran/Houston Chronicle hide caption

itoggle caption Mayra Beltran/Houston Chronicle

Millennials seem to prioritize the environment, but may want to dissociate from the "treehugger" baggage of the term "environmentalist." Getty Images hide caption

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Five industrial wind turbines form part of the Gorona del Viento power plant on the island of El Hierro. By the end of this year, the power plant is set to generate 100 percent of the energy El Hierro needs, making it the world's first energy-independent island powered only by renewables. Lauren Frayer for NPR hide caption

itoggle caption Lauren Frayer for NPR

An engineer oversees the gas distribution system of Hungary's gas pipeline operator FGSZ in Kiskundorozsma, in August. The distributor announced that it would cut off gas supplies to Ukraine. Laszlo Balogh/Reuters/Landov hide caption

itoggle caption Laszlo Balogh/Reuters/Landov

Vera Cole is president of the Mid-Atlantic Renewable Energy Association, a group arguing against proposed rules in Pennsylvania that would put stricter limits on how much grid-connected solar power homeowners can produce on their property. Jeff Brady /NPR hide caption

itoggle caption Jeff Brady /NPR

In Del Norte, Colo., Public Works Supervisor Kevin Larimore shows off solar panels that provide electricity for the town's water supply. Despite generating its own solar energy, the town is still at risk of a blackout if its main power line goes down. Dan Boyce/Inside Energy hide caption

itoggle caption Dan Boyce/Inside Energy