Inhabitat's Week in Green: frozen energy, spray-on solar and the hydrogen peroxide helicopter

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.

It was a big week for green transportation as San Francisco broke ground on its massive green-roofed Transbay Transit Center and unveiled plans to install 5,000 EV charging stations throughout the Bay Area. We were also wowed by several fun new forms of alternative transportation - a single-person helicopter that emits nothing but water vapor and a human-powered car that can go 30 MPH while driving uphill!

It was also an exciting week for energy storage tech as New York prepared to power up the world's first grid-scale flywheel energy plant and researchers cracked the code on a new cryogenic energy storage system. We also showcased a plan for a ribbon-like solar field that unfurls over the desert and saw researchers unveil a transparent solar spray that can transform practically any surface into a sun-capturing source of energy.

In other news, solar tech energized the arena of interior lighting as we showcased an adorable solar-powered table lamp and were dazzled by this set of folding OLED origami lights. Finally, a team of scientists blew our minds with this light-bending invisibility cloak made from gold-coated silk.