Last month, the Federal Energy Regulatory Commission approved Order 2222, a groundbreaking effort to open up U.S. wholesale energy markets to aggregated solar systems, smart inverters, batteries, electric vehicles, smart appliances, grid-responsive building controls and other distributed energy resources (DERs). But ordering the country’s transmission grid operators to comply with FERC Order 2222 doesn’t mean those multibillion-dollar markets are open to the hundreds of gigawatts' worth of DERs coming onto U.S. power grids — at least, not yet.