Ketujuh Doms/Shutterstock

Wind and solar power are both well established sources of renewable energy, but for nations with plenty of coastline, a promising emerging technology called osmotic power offers another possibility. Osmotic power involves generating electricity from the natural interaction between saltwater and freshwater, and Japan has turned the intriguing idea into a working power plant. The technology uses a membrane that separates saltwater from freshwater. The membrane allows water molecules to pass through from the freshwater side into the saltwater side, while blocking most of the salt.…