Nearly one in five Baltimore Gas &: Electric Co. customers is buying power from a third party, according to Maryland's largest electric utility.

BGE said Tuesday that more than 200,000 out of 1.2 million residential electric customers were buying power from third party suppliers, double the number of a year ago.

"BGE customers continue to recognize that they can save real money by purchasing their electricity from third-party suppliers, "Kenneth W. DeFontes, president and chief executive officer of BGE, said in a prepared statement. "The number of third-party suppliers offering to sell electricity to BGE customers continues to grow, providing new opportunities for BGE customers to purchase their electricity at prices that may be lower 'than BGE's Standard Offer Service. This is the strongest signal yet that competition related to electricity supply is working in Maryland."

Additionally, the company said about 40 percent, or more than 45,000, of its business customers were purchasing power from third-party suppliers.

Paula Carmody, who heads an independent state agency called the People's Counsel that represents Maryland's residential consumers of electricity, said determining whether deregulation is delivering on the promises from 1999 when it was signed into law, is more than just how many people have signed up with a third party.

 She said a big question is whether the choices are delivering lower prices for customers. "Is it a success?" Carmody said. "I'm not sure. I would say the jury is still out."

Thomas A. Firey, an analyst with the Cato Institute and the Maryland Public Policy Institute, said the increased number of people choosing a third-party supplier was a good sign that customers were getting the hang of shopping for power. But, he said, it was not proof that the promise of deregulation when it was passed was being fully delivered.

"If policymakers were worried people couldn't handle shopping for electricity this shows more and more people are doing it," Fire'y said. "But, if people thought it was going to drop electric prices drastically - well, that's not going to happen."

Carmody said a big test will come over the next year or so as the default rate for electricity continues to drop and the gap between what third parties can offer and what people would pay for not choosing a new provider continues to narrow.

In Maryland's deregulated system, the electric industry is split into supply companies and delivery companies.

Customers in BGE's service area can choose to purchase electricity from any energy supplier licensed by the

Maryland Public Service Commission and registered with the company. All electric delivery, no matter who the supplier is, is provided by BGE. Under deregulation, electricity customers receive what is called standard offer service if they choose not to purchase power from another retail supplier.

The default kilowatt-hour rate for electricity has been declining in recent months, and from June 2011 through

May 2012, the rate is expected to decrease as much as 14 percent. Wayne Harbaugh, BGE vice president for pricing and regulatory, said he felt confident that the trend of people shopping for power would continue to grow.

"Once customers "start to shop, they will continue to do so," Harbaugh said "They'll be shopping for the best deals just like they do already for things like wireless service."