More than 100 angry Mission Hill residents shouted down a hearing Wednesday night on the draft environmental impact statement of the proposed Medical School area power plant, before the hearing ever got under way.

The proposed $50 million power plant, to be built by Harvard and the Medical Area Service Corporation which is composed of ten medical-related institutions in the area, would provide electricity, steam, chilled water, and refuse incineration to the participating institutions.

Residents at the hearing, held at Harvard's Vanderbilt Hall at the Medical School by the Boston Redevelopment Authority (BRA), demanded that the BRA tell the people of Mission Hill how they can stop the power plant from being built.

After one and one-half hours of protests, Mace Wenniger, director of development and planning for the BRA, dismissed the gathering because, he said. "The tenor of the meeting was one where further constructive comments and questions are not forthcoming."

Wenniger said another hearing will be held, but that the hearing will this time be more closely coordinated with the Mission Hill planning commission and be held at a place agreed to by Mission Hill residents beforehand.

The protests began with Mission Hill resident Charlotte Ploss taking the microphone at the front of the Vanderbilt dining room before the hearing could be called to order by the BRA.

After speaking for a few minutes about how the hearing should not have been held on Harvard property, she demanded that residents "say no to this meeting before it begins." She was greeted with a minute-and-a-half ovation.

Kevin Fitzgerald, state representative for Mission Hill and Jamaica Plain, spoke after Ploss.

Fitzgerald said he did not receive an environmental impact statement, which was supposed to be sent to all Mission Hill community leaders by the BRA. He stormed out of the meeting after a short speech, demanding that residents not let the hearing get underway.

John Grady then look the microphone and said the meeting could not take place until the BRA told the community people how the plant could be stopped.

Grady and Ploss repeatedly questioned the BRA officials about how to stop the power plant. Each time the BRA officials tried to begin the hearings they were interrupted by residents shouting derogatory comments about the plant, Harvard, the hospitals and the BRA.

During the meeting some residents posed questions to Donald C. Moulton, assistant vice president for community affairs, about what will happen to the homes on the power plant site bounded by Brookline Ave., Binney, Francis and Peabody Sts.

"The land was acquired by the University for institutional development." Moulton said. "Our intention is to tear the buildings down once they are vacant."

About 30 people who are still living in the area in which the power plant is slated to be built received eviction notices in early May.

John J. Murphy, assistant manager in Boston Edison's electric and steam sales department, asked at the meeting that the deadline for comments on the impact statement, which expired that Friday, be extended two weeks.

When Murphy attempted to present his comments on what he called the "serious mistake" of building a large scale power plant in a hospital and residential area, residents refused vocally to let him do so, claiming that the meeting was not an official hearing until, held with Mission Hill planning commission comment.

The Massachusetts clearing house extended the deadline 15 days on the day following the hearing.

Grady said after the meeting "what we saw at Vanderbilt Hall was a small victory."

"It was important because it exposed the entire political nature of the process" of trying to erect the power plant, Grady said.

Although the plant construction is scheduled to begin by the end of the summer, some residents said last week they hope to stop the plant or at least get construction postponed until all the alternative to the plant are examined.

"Never, never will the plant begin to be built by the summer even if they have everybody's o.k.," Barbara Westmoreland, a resident of Mission Hill who attended the Mission Hill meeting, said Saturday.

Westmoreland said some residents are determined to check Harvard hospital expansion in the area and that they see the power plant as the center of the struggle.

Moulton said after the meeting. "It is important in my judgment that the facts of the impact statement were not discussed. It is unfortunate people did not have an opportunity to comment on the statement for the record."

Moulton said he wants to discuss the reasons for building the total energy plant because Harvard is convinced they are "sound reasons."

"Stopping the total energy plant will at this stage of the game create a power shortage by 1977," Moulton said.

Moulton said the MASCO plant would provide steam, hot water and refuse incineration to the $50-million Mission Hill housing project which is sponsored by Harvard and subsidized in part by federal and state agencies.

He said the project will supply 774 units of mixed income housing which would handle any residents displaced by the power plant's construction