Ethan Novek was digging a hole in the sand at a beach in Connecticut when he noticed something that got him thinking. The seawater that seeped into the hole was rising at the same rate as the tides offshore. What if that seepage could be harnessed for energy in wells onshore, rather than out in the trickier ocean environment?

That idea kicked off the first in a chain of experiments that eventually landed Novek at Yale University, leading a research project while he was still in high school. Starting after that summer at the beach before his freshman year, Novek ran successive experiments at his school's lab. By the time he was a sophomore, he had arrived at a simple and