Each week our friends at Inhabitat recap the week's most interesting green developments and clean tech news for us -- it's the Week in Green.

DNP Inhabitat's Week in Green TKTKTK

The Northern Hemisphere is finally beginning to wake up from a long, cold winter, and green vehicles are taking to the skies. This week Korean automaker Hyundai unveiled a multi-rotor flying electric car for congested cities and SolarWorld and PC-Aero announced plans to launch two new solar-powered electric airplanes at an air show in Germany. Speaking of sun-powered planes, the Solar Impulse just made its final test flight around the San Francisco Bay Area before embarking on a cross-country voyage next week. Even cycling is reaching new heights -- bike hacker Richie Trimble recently built a two-story-tall bike that soars above car traffic.

In green energy news, this week Lockheed Martin announced plans to construct the world's largest ocean thermal energy conversion plant off the southern coast of China. In Hamburg, construction is moving forward on the Renewable Energy Bunker, an abandoned WWII bunker that is being retrofitted with enough solar panels to provide heating for 3,000 households and electricity for 1,000 homes. The European Union just launched SUPRAPOWER, a four-year project aimed at developing a next-gen wind turbine that could cut manufacturing costs by 30 percent. And a team of IBM researchers is developing a super-efficient solar concentrating dish that could collect 80 percent of incoming sunlight and convert it into energy.

Scientists continue to make major advances in 3D-printing technology for the medical community and for wider consumer applications. In an effort to do away with agonizing waits on organ transplant lists, San Diego-based bioprinting company Organovo has successfully created functional 3D-printed livers. A Singapore-based team of scientists just launched a new personal Panther 3D printer that is made from rugged stainless steel and aluminum. In New York, the Inhabitat team dropped by the 3D Printing Conference and Expo -- the first trade show of its kind -- and we rounded up some of our favorite 3D-printing innovations on display. And Tecnologia Humana 3D is using sonogram data to 3D print miniature models of unborn babies for their parents to hold.

Unmanned drones have gotten a bad rap for their role in the war on terror, but drones could be used as a powerful technology to protect the planet if they're put in the hands of scientists and environmentalists, we argue in a new essay. But protecting the environment isn't the only unexpected new use for unmanned drones; Louisiana farmers are using drones to hunt invasive wild pigs that carry diseases and spread noxious weeds. In other green design news, artist Michael Jantzen has released designs for a solar-powered seed-sowing machine that would plant flowers at sites of environmental destruction. Ecuadorian architects Jose María Sáez and David Barragán recently completed an impressive prefab home using 900 Lego-like concrete blocks. And Swiss company ÖKO has utilized NASA filtration technology to create a bottle that can turn sodas (or anything else) into water.