Consumer advocates took to the streets of Phoenix recently to protest against an Arizona utility's efforts to bill customers using a so-called "demand charge." If approved, Arizona Public Service would be the first utility in the country to place most of its residential customers on that kind of rate plan. Will Stone/KJZZ hide caption
Logger Greg Hemmerich and his crew feed low-value trees into a wood chipper, before bringing the chips to ReEnergy Holdings' biomass plant in Lyonsdale, N.Y. David Sommerstein/NCPR hide caption
Eric Frumin (right) stands in front of his solar panels on the roof of his Brooklyn home alongside architect David Cunningham (left) and AeonSolar's Allen Frishman (center). Courtesy of Eric Frumin hide caption
Solar-powered lights make a dramatic difference in the lives of Tanzanians who had no electricity. Rachel Ambrose/Courtesy of Off-Grid Electric hide caption
One of the sites for the Department of Energy's Strategic Petroleum Reserve lies within salt caverns 2,000 feet below the ground near Freeport, Texas. Jeff Brady/NPR hide caption
U.S. Energy Secretary Ernest Moniz takes part in a press conference at the end of the 2015 meeting of the International Energy Agency Governing Board on Nov. 18, 2015 in Paris. ERIC PIERMONT/AFP/Getty Images hide caption
The sun sets over Alexandria, Egypt. The Brits brought daylight saving time to Egypt, but the country is currently DST-free. Peter Langer/Design Pics/Corbis hide caption
A world in light and dark: This satellite view shows where electric lights are in high usage. Buyenlarge/Getty Images hide caption
Rob Oberg delivers oil to a home in south central Vermont. He works for Keyser Energy in Proctor, Vt., which provides heating fuel to about 5,000 customers. Nina Keck/Vermont Public Radio hide caption
The Heartland Biogas facility in Weld County, Colo., is one of the country's largest waste treatment plants that converts methane to natural gas. Rebecca Jacobson/Inside Energy hide caption
Onlookers come to admire the self-proclaimed "Miracle on 34th Street" in the Baltimore neighborhood of Hampden. But not every country has as much electricity as America does. Patrick Semansky/AP hide caption
The University of Toronto's solar-powered pond aerator could help fish farmers in Bangladesh earn up to $250 of extra income a year. Courtesy of Powering Agriculture and University of Toronto hide caption
At a brick kiln in India's rural state of Uttar Pradesh, workers use solar lanterns to illuminate their paths. Rubén Salgado Escudero/National Geographic hide caption
OPEC oil ministers met Friday in Vienna but failed to agree on whether to set new production limits. Ronald Zak/AP hide caption
