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, a program manager at Google.org, the company's corporate philanthropy arm. "We depend on a whole ecosystem of utilities, device makers and policies that would allow consumers to have detailed access to their home energy use and make smarter energy decisions."

"Smart grid" is the new buzz phrase in the electric business, encompassing a variety of approaches that involve more communication between utility operators and components of the grid, including transformers, power lines, customer meters and even home appliances like dishwashers.

"They've been putting a chip in your dishwasher for a long time that would allow you to run it any time you want," said Rick Sergel, chief executive of the North American Electric Reliability Corporation, an industry group that sets operating standards for the grid.

If the utility could "talk" to the dishwasher, it might tell the machine to run at 2 a.m. and not 2 p.m., or it might tell the homeowner how much money would be saved by running the dishwasher at a different hour.

"It provides an opportunity to create dancing partners that will help the system balance itself," he said.

It also might be useful for plug-in hybrid cars, which will draw significant amounts of energy, perhaps doubling the electric demand of a small household. A smart grid would recognize the car wherever it was plugged in, the way a cellphone network recognizes a mobile phone when it is turned on.

The grid could bill the owner of the car for recharging the battery no matter where the car was plugged in. It would charge the owner a rate based on the time of day or night. If the car were left plugged in, the grid could decide when to charge it at the lowest rate.

The stimulus bill now going to a House-Senate conference committee has allocated $4.4 billion for "smart" technologies, including four million of these next-generation monitors, called smart meters. Proponents say that could make more effective use of existing power lines and generate employment.

"You can hire a lot of people to install smart meters," said James Hoecker, a former chairman of the Federal Energy Regulatory Commission, which has some jurisdiction over transmission lines.