Lutz Wiese of Vattenfall power company refuels a hydrogen-powered Mercedes at a filling station in Berlin. Vatenfall is a partner in the world's first direct wind-hydrogen power plant, in northern Germany. Using wind-generated electricity to create hydrog
How do you balance the ebbs and flows of wind and solar power to use it when and where it's most needed? Turn it into hydrogen and use it to drive cars.
A surge in wind turbines like these have helped Germany generate more than 25% of its electricity from renewable sources. Since Germany's electricity system is interconnected with most of the rest of western Europe, the overall percentage of this kind of
Too much renewable power? A German engineer comes up with a way to store excess renewable energy, take pressure off the grid and ease the way for the adoption of more wind and solar power in a country that's already way ahead of most of the rest of us.
Solar power production has grown more than 25 times over the last decade in Germany, spurred largely by big incentives for small producers to get into the market. But sunshine and wind power are intermittent, so engineers and others are looking for ways t
Unhappy with the economics of his rooftop solar panels, a German tinkerer invents his own electricity storage system that saves users hundres of dollars a year, makes it easier to integrate renewables into the grid, and wins an award for renewable product of the year.
People cast shadows on the sand as they walk at low tide.
Sand is the building block of megacities around the globe. People use 40 billion tons of it a year. But it's finite. And like oil, controlling it is a deadly endeavor.
Ethiopia's Grand Renaissance dam on the Blue Nile, shown under construction in March of 2014. Egypt claims most of the water in the 4,000 mile-long river that it shares with 10 other countries, and fears the $4.7 billion Renaissance dam will reduce the wa
Not long ago, Egypt all but threatened war if Ethiopia built a huge dam it was planning on part of the Nile River. Now the two countries have signed breakthrough agreement to allow the dam to go ahead. It's a big deal in a region with a history of tension over scarce water resources
A one-horned rhino named Baghekhaity stands next to its 10-day-old calf at a zoo in Guwahati, in the northeastern Indian state of Assam.
What do you do when all other efforts to persuade locals to protect endangered rhinos have failed? Pay them to harvest the rhinos' dung and use it to make paper. That's what an Indian startup company is trying, with early success.
A man takes a shower as policemen patrol during an operation in Rio de Janeiro's Mare slums complex on March 30, 2014.
Brazilians are notoriously lavish bathers, taking as many as three showers a day. But as the country faces a major drought, they're trying to find way to keep up the shower numbers while still saving water.
Protesters march through São Paulo recently demanding equitable distribution of water throughout São Paulo state. Unofficial rationing has brought frequent water outages to neighborhoods throughout the Brazilian megalopolis of 20 million people.
The unprecedented water crisis in South America's largest city is leading citizens to change everything, from how they use water to how they engage with politics. But while the government is taking action, residents say it's not nearly enough.
A worker fills a water tanker for distribution to a hospital in São Paulo in February. Residents throughout the metropolitan region of 20 million people are taking emergency measures amid a severe drought.
São Paulo is facing an unprecedented water crisis that many saw coming, but no one did much to prevent. And with reservoirs hovering near 10% of capacity, many residents are turning to unhealthy stopgaps and worrying about unrest.
The polar jet stream carries weather around the Northern Hemisphere. Climate researcher Jenifer Francis believes the rapidly warming Arctic is slowing and warping the jet stream, allowing Arctic air to spill farther south in some places.
There may be a counterintuitive explanation for the deep freeze that hit New England this winter: The rapidly warming Arctic is causing big disruptions in the jet stream, which carries weather across North America. Is this the worst winter you've experienced?