New York City may soon face an electricity shortage, as the current supply will not accommodate the demand from the major commercial and residential real estate developments planned over the next 20 years, a report released yesterday warned.

The report said that based on current projections for power demand, the supply of locally produced electricity would fall short of state-mandated thresholds between 2010 and 2015, and it called for new investment in power plant construction and improved energy efficiency.

“Without this power, New York ceases to grow,” a top real estate executive for the Rudin Management Company, John Gilbert, who helped write the report, said.

Sponsored by several pro-business, construction, and real estate organizations, the report was released at a forum held by the New York Building Congress.

Attending the forum was a Democratic candidate for governor, Attorney General Eliot Spitzer, who attacked the Pataki administration’s development record. Mr. Spitzer said that if elected governor he would spend more money on infrastructure improvements for the city.

He also criticized the anemic pace of the redevelopment of ground zero, the lack of progress in developing the Hudson Yards area, extending the no. 7 line subway, and building a Second Avenue subway line. The attorney general called for increased transparency in the state development authorities, which he said would prevent the state from making “political deals” rather than decisions based on “the wisdom of economic development.”

“Competence matters,” Mr. Spitzer said.

The attorney general also endorsed increased state involvement in helping the United Nations build a new headquarters in New York City.

A spokesman for Mr. Pataki, Saleem Cheeks, defended Albany’s record of funding infrastructure projects.

“Since the governor has taken office, there has been $102 billion for highways, bridges, transit systems, and other infrastructure improvements,” he said.