If people knew how much electricity they were using every time they turned on the lights, fired up the oven or lowered the thermostat on their air-conditioner, they would make smarter decisions about their energy use, and presumably, conserve more.

That’s the idea behind a prototype service that Google unveiled Tuesday, which my colleague Matthew Wald and I wrote about in Tuesday’s paper. The service, which will be called Google PowerMeter, will allow users to measure their energy use in real time. It one of many new consumer products that would be enabled by “smart grid” technologies, and it is one of Google’s many initiatives in the energy area.

As a way to attract partners to its endeavor, Google is unveiling the prototype for PowerMeter well before it has a functioning product available. The company also hopes that the announcement will bolster its own advocacy efforts at the state and federal levels in support of policies and investments that will promote the development of a smart grid.

“We are in conversations with a number of device makers and utilities,” said Kirsten Olsen Cahill, a program manager at Google.org, the company’s corporate philanthropy. “We’d love to talk to more people and build out this ecosystem.”

For now, Google developed its prototype using an electricity measuring device that clamps onto a house’s main circuit breaker and sends the information back to Google’s servers, where it is charted. Google plans to enhance PowerMeter with “social” tools that will allow users to compare their electricity consumption with that of their neighbors or friends. And it plans to allow third parties to develop their own applications that would enhance its usefulness. A programmer, for instance, could create a tool that normalizes the data for variations in weather.

About 30 Google employees, including co-founder Sergey Brin, are currently using PowerMeter in their homes. Ms. Olsen Cahill said that on a recent morning she checked the tool on her computer when she woke up and noticed that her usage was about 600 watts, or triple her typical consumption level. That sent her looking around the house for answers.

“It turns out my husband had used the toaster oven the night before and the dial got stuck,” Ms. Olsen Cahill said. “It had been on all evening.”

Google said PowerMeter had helped sharply reduce energy use at one Googler’s house: power savings were down by 44 percent and energy bills were cut by 56 percent over the past year. (In an recent experiment in Oklahoma, which used technology from a company called Silver Spring Networks, homeowners who had real-time information about their power consumption and the price of electricity at that moment saved an average of 15 percent on their bills.)

PowerMeter was developed jointly between Google.org and a small team of engineers working at Google itself. Google said that it developed PowerMeter because it fitted with both its goal to organize the world’s information and its environmentally oriented philosophy and philanthropic goals.

The company said it had no plans to generate revenue from the service at this time, either through a fee or through advertisements. Then again, Google often releases products free and later decides to place advertisements on them. And of course, Google, which excels at making money from the data it collects about users’ online activities, could probably figure out novel ways to make money based on detailed information about their energy use.

Google also hopes that the PowerMeter announcement will raise the profile of its advocacy efforts. PowerMeter’s success depends on the deployment of so-called smart meters that measure energy consumption in real time. While some state regulators have ordered utilities to deploy smart meters, their focus has been on their use by utilities and grid managers, said Michael Terrell, a program manager at Google.org, who works on the company’s energy policy initiatives.

“There is not much in the mandates about how the information should flow to consumers,” Mr. Terrell said. He said that he hoped PowerMeter, and similar tools for consumers being developed by other companies, would help showcase the importance of getting information into consumers’ hands.

“Ultimately when you get people engaged you will see demand pull from people to get these services,” he said. “We are at the moment where we have the potential to revolutionize the way people use energy.”

Mr. Terrell, who also has PowerMeter installed in his San Francisco apartment, said the tool could be an eye-opener: turning on his kitchen halogen lights, for instance, raised his baseline energy use by a startling 100 percent, he said.

“It changes the way you think about electricity,” he said.