Here are some links on the question.

• Distributed generation, from Wikipedia
• Decentralized control techniques applied to electric power distributed generation in microgrids, a doctoral thesis by Juan Carlos Vásquez Quintero
• Distributed generation and microgrids for small island electrification in developing countries: A review, by Indradip Mitra, Thomas Degner, Martin Braun
• Stability, power sharing, & distributed secondary control in droop-controlled microgrids, by J. W. Simpson-Porco, F. Dorfler, F.Bullo, Q. Shafiee, J. M. Guerrero
• A 2013 article from Bloomberg Business Week on “Why the U.S. Power Grid’s Days Are Numbered“, including the quote
  

  The big complaint, though, is about subsidies. “I don’t characterize distributed generation in and of itself as a threat,” says Nick Akins, CEO of Columbus (Ohio)-based American Electric Power. “I characterize the regulatory scheme that supports it as a threat.”

• Decentralized master-slave operation of microgrid using current controlled distributed generation sources, by V. Verma and G. G. Talpur
• Operation and control microgrid and distributed Generation, by M. Shahidehpour
• LocalGrid marketing reference literature
• Cape & Vineyard Electric Cooperative (“CVEC”)
• Siemens approach to microgrids, including a review of their controls solution

A representative from CVEC explained in a presentation that, in their experience, undersupply of electrical power was not a problem, rather oversupply was a problem. However, she emphasized, as long as capacity was overbuilt, their engineers felt oversupply could be managed by having available switchable large resistive loads, so unneeded current just went into Joule losses when necessary.