Sigma Designs has bought Zensys for an undisclosed amount. Zensys has been trying to gain traction in the smart grid market but hasn't experienced a tremendous amount of success.

Zensys is the primary driver behind Z-Wave, a wireless, energy-efficient protocol that allows lights, appliances, security cameras, thermostats and other devices to talk to each other. Z-Wave is a single chip solution and is cheaper than competing technologies like ZigBee and WiFi, say advocates.

Although Z-Wave might not cost a lot to add into products, it has been falling behind in the battle for design wins and utility trials. Z-Wave has been incorporated in only about 250 products.

At the moment, ZigBee seems to be the leader. Tendril Networks, one of the primary proponents of ZigBee for controlling energy consumption in the home, has landed trials and/or development deals with 29 different utilities. One utility next year will begin to deploy Tendril's technology in homes. By the end of next year, Tendril says its meters and other parts will be going into 5,000 to 10,000 homes a month (see Tendril Expands Its Reach in Smart Homes).

ZigBee was initially devised with consumer electronics in mind and was slow to take off in the marketplace: The growing popularity of smart grid and the need to wire appliances in the home essentially gave the protocol a second lease on life.

At the same time, companies such as GainSpan and GridNet have teamed up to devise smart grid solutions based on WiFi and WiMax, two networking technologies from the computing world (see Get Ready for the WiFi Thermostat and The Next Smart Grid Technology: WiMax). They argue that these technologies will be easier for utilities to adopt because IT managers, electrical engineers and chipmakers are more familiar with things like WiFi. WiFi will also let utilities exploit existing infrastructure, such as the wireless router in your home and the WiMax antennas funded by ClearWire.

Echelon and a few others, meanwhile, are touting broadband over power line. So far, around 25 million household smart meters in Italy have been rigged up with broadband over power line and Anchorage, Alaska has adopted the protocol to control its street lights. There is also an effort underfoot to make it easier for manufacturers and utilities to accommodate both power-line networking and ZigBee (see Will Smart Grid See a Push for Power-Line Networking).