Do green energy marketers really pose a threat to utilities’ monopoly on power? An interesting report this morning says yes, if you’re talking about deregulated markets such as Great Britain. That’s where companies like Co-Operative Energy and Good Energy are trying to eke out customers for green power from the 99.5 percent of power supplied by the country’s six big utilities. In the United States, companies like Green Mountain Energy (now owned by NRG Energy) have constructed similar business plans around selling renewable power (mainly wind) to retail customers — different than the big, block power purchases we’ve seen from buyers like Google. As for how utilities will manage the growth of distributed, customer-owned power generation such as rooftop solar panels or campus backup power generators, that’s where microgrid operators like Balance Energy, Lockheed Martin, Viridity Energy and others want to play. It’s an interesting set of concepts to watch — and still a long way from major market penetration. Most of the United States remains non-competitive, with traditional utility-customer relationships that would make it difficult for new entrants to gain market share for their differentiated power supplies.