HARTFORD, Conn. — Power companies in New England are beginning work on a nearly half-billion-dollar plan to upgrade the region’s electric grid to make way for appliances that can shut down to reduce electric bills, improve energy conservation and connect to wind and solar energy.

The first step is replacing decades-old meters with so-called smart meters that detail the use of computers, appliances, TVs, lights and other household equipment.

The new meters – the front line of plans for an advanced electricity grid –communicate with utilities and can respond to constantly changing energy prices.

Customers will be able to respond to electricity prices in real time and shut down appliances to save money. Utilities can offer better rates as incentives for using appliances in off-peak hours.

Future appliances may even be able to respond to price signals and shut down automatically.

“Smart meters allow us to see what’s going on in the system and allow customers to see what they’re using, when they’re using it and what the cost is,” said Robert V. Jolly Jr., general manager of Marblehead Municipal Light Department, a municipally owned power company in Marblehead, Mass.

“The question is, Will they modify their usage?”

Michael Sachse, senior director of government affairs and general counsel at OPOWER, an Arlington, Va.-based software company that helps utilities meet efficiency goals, said utilities must show their customers the benefits of upgraded electricity measurement.

“Just giving people a lot of data is not going to be particularly useful because the truth is that while no one wants to waste electricity and no one wants to pay higher electric and gas bills, people have busy lives and don’t have time to analyze electric bills,” he said.

OPOWER, which is working with a utility that serves New England, analyzes electricity use for residential users to compare their use with homes of a similar size and heating type.

The federal government’s push for an upgraded power grid in the United States will lead to changes comparable to transformations brought about by the personal computer, said Allen Stamp, a Vermont utility official.

Stamp, program manager for smart grid deployment at Vermont Transco, said a modernized power grid is “really about the consumer being empowered to save dollars.

“One person described it as an Internet dot-com mentality coming into use with the electric power system,” he said. “It’s a fundamental change.”

The U.S. Department of Energy has awarded $230 million in federal stimulus funding – matched by the recipients – to New England utilities, municipal power companies, private companies and a cooperative that are installing new meters. Companies have three years to complete the projects.

About $4 billion is being spent nationally on modernizing electricity grids.

Power companies will benefit by seeing patterns of electricity that show when less capacity is required, leading to reduced transmission costs and eliminating the need to build power plants.

In addition, the new meters will identify outages, avoiding tedious searches and increasing response time.

Unitil Corp., a distributor of natural gas and electricity in Maine, Massachusetts and New Hampshire, has installed new meters without stimulus funds.

A pilot program is planned for next year offering customers lower rates by limiting air conditioning and other appliance use during heat waves, said Justin Eisfeller, director of the company’s energy measurement and control.

Customers can track electricity use online and Unitil will provide software to monitor real-time power consumption, remote programmable thermostats and outlets that measure electricity.

In addition, Unitil will provide thermostats to houses with air conditioning that can be turned off by the utility to conserve energy. A customer can override the shutdown but will get a credit on their bills if they allow their air conditioners to be turned off.

Stimulus money for New England’s projects ranges from $800,000 to write software to monitor weather for wind power on Cape Cod to nearly $96 million to install about 600,000 high-tech electricity meters in Maine.

At least 1 million customers in the region will be affected. Only some companies are participating; Rhode Island was the only state in New England where power companies did not receive federal money.

John Carroll, spokesman for Central Maine Power Co., a subsidiary of Iberdrola USA, said the stimulus funding makes the project possible. The money will pay nearly half the cost of replacing meters for 600,000 residential and business customers.

Central Maine Power has proposed replacing meters for several years, but regulators said rates would have risen excessively to pay for the project, Carroll said.

Stamp, of Vermont Transco, said the new grid will help make electric vehicles more broadly available and generate electricity closer to where it’s used to reduce energy lost in transmission.

“We’re just starting to begin figuring out where it will take us,” he said.