
PETTEN, Netherlands — Hidden behind undulating sand dunes and fog rolling off the North Sea, the sprawling, gated campus of the Energy Research Center of the Netherlands (ECN) sits on a spit of land about an hour north of Amsterdam. Crying gulls circled a building crammed with pipes, machinery and scaffolding, while in a nearby control room, engineers in yellow hardhats peered at a confounding series of digital flowcharts and graphs. They were working on one of clean energy’s intransigent problems: how to turn waste into electricity without producing more waste.