Google will announce its entry Tuesday into the small but growing business of “smart grid,” digital technologies that seek to both keep the electrical system on an even keel and reduce electrical energy consumption.

Google is one of a number of companies devising ways to control the demand for electric power as an alternative to building more power plants. The company has developed a free Web service called PowerMeter that consumers can use to track energy use in their house or business as it is consumed.

Google is counting on others to build devices to feed data into PowerMeter technology. While it hopes to begin introducing the service in the next few months, it has not yet lined up hardware manufacturers.

“We can’t build this product all by ourselves,” said Kirsten Olsen Cahill,