A private consume group yesterday criticized the Virginia Electric and Power Co. and Baltimore Gas and Electric Co. for "generally mediocre pollution control performance" during the last five years at their coal, oil and gas-fired power plants.

The 430-page report by the New York-based Council on Economic Priorities, a nonprofit research organization, said any improvement in pollution control at the 15 major utilities studied has been canceled by the increase use of coal by the power companies.

It labeled BG&E the "least improved" of all the companies, while Vepco retained its middle-level rating. The study, called, "The Price of Power/Update," said heat emissions, or the discharge of heated air or water into the environment, had declined overall but pollution from plants newly converted to coal had canceled out most of the gain.

President Carter's energy plan calls for 85 per cent of the nation's power to be generated by coal-burning plants by 1985. Environmentalists have said such a conversion to coal would require a massive overhaul of the nation's transportation system, in addition to increasing air pollution, the coal mining death rate and the visual and water runoff pollution from coal slag.

The CEP spent at least $50,000 and two years reviewing the pollution emissions of 119 fossil fuel plants in 15 electric utilities, which together represent 35 per cent of all the nation's electricity from fossil fuels.

The three top performers all use low-sulfur coal or oil and/or natural gas to fuel their plants, while the worst polluters use high-sulfur coal and use no desulfurization equipment on their chimney flue gas, CEP reported. The best, measured in terms of pounds of emissions per megawatt hour of electricity generated, were Pacific Gas and Electric Co. of San Francisco; Southern California Edison Co. of Rosemead, Cal.; and Florida Power and Light Co. of Miami.

"The six worst include the four largest coal-burning utilities in the nation . . . which burn large amounts of dirty high-sulfur coal at large plants with generally medioacre pollution control levels," the report said. The nation's largest utility, the Tennessee Valley Authority, was ranked the worst polluter overall.

The CEP report estimated that installation of up-to-date pollution controls on ali 119 power plants would cost between $9 billion and $13 billion. For BF&E, the smallest of the 15 utilities studied, the cost would be between $100 million and $144 million.

Vepco would have to spend between $541 million and $799 million, CEP estimated.

"The industry, with a few exceptions, implements state-of-the-art pollution control systems only when legally required to do so," the report stated. It said there was an "urgent need" for a federally directed control compliance, since data supplied to CEP was found to be incomplete or in conflict with other data supplied to other agencies.

"The rapid shift to coal as the primary fossil energy source is likely to delay, and in some cases prevent, the achievement of air quality goals in those regions that will bear the brunt of coal conversion and new plant sittings" under any new energy plan, the study said.

Vepco was ranked eighth overall and BG&E was sixth of the 15 utilities studied.

A BG&E spokesman said the study's figures were out of date. Nuclear generating plants that have begun operating since the study was completed in 1975 have reduced the company's dependence on coal and oil and thus reduced its pollution, the spokesman said. The company's three Baltimore plants have cut use of fossil fuels by 35 per cent, he added.

The study criticized BG&E's partially-owned Keystone and Conemaugh plants in western Pennsylvania for a high level or particulate emissions, often soot. Heated water discharged from three Baltimore plants "may severely disrupt the fragile aquatic ecosystem in the Chesapeake Bay estuary in the plants' vicinities," CEP said. It added that BG&E had show poor cooperation with the study, refusing to fill out its questionnaires or provide additional information.

M. L. Brehmer, Vepco's executive manager for environmental services, responded in a statement that the CEP study was based on invalid comparisons between utilities of varying sizes with differing mixes of power plant types.