Scientists have long talked about black silicon (that is, silicon with nano-sized structures) having the potential to trump conventional solar power, and there's now some proof that this is happening. Aalto University researchers have developed black silicon solar cells that achieve a record 22.1 percent efficiency when turning the Sun's rays into usable energy. That's a 4 percent absolute boost over the previous best, and good enough that the technology could finally be ready to reach the market and replace existing solar panels. Black silicon is far better suited to collecting sunlight at low angles, which is common in northern regions -- you wouldn't have to live in a sunny, forgiving part of the world to get the most out of clean energy. It should be cheaper, too. So long as these black cells translate well to mass production, you may have an easier time ditching the conventional power grid.