Demand response — the business of turning down electricity use at homes, offices, factories, and other such sources of demand, to help manage grid needs — has changed a lot over the past few years. What grew up as a specialized, utility-focused enterprise has, with the growth of the smart grid, expanded to include all kinds of new technologies and business models.

That means smart-meter-connected homes, as well as smart building technologies that shave and shift energy consumption for commercial and industrial clients. The purpose of demand management has also expanded, from the hour- or day-ahead power-down calls of the past to fast-reacting, automated systems to help balance grid frequency, ease congestion on specific power lines, or even mitigate the ups and downs of wind and solar power.

So what are the top developments in this strangely named, sprawling line of business? Here are a few takeaways from 2012:

via 2012 Top Trends in Demand Response : Greentech Media.