Microgrids that can disconnect from a centralized electric grid and operate independently are sizzling hot these days.

Cities vulnerable to storms want them. Neighborhoods interested in renewable energy and lower power bills want them. And now, traditional utilities want them to make their systems more reliable and to expand their business.

So when will microgrids dot American cities and towns? Answer: when new policies reduce historic barriers created by monopolies and open the door for decentralized and third-party energy arrangements.

But utilities will fight to protect their marketshare and we’re now seeing the beginning of a struggle that will likely take years to play out.