The absolute certainties about the benefits of nuclear energy that dominated electric utility company thinking in the 1960s have been replaced here by caution and concern about the costs, the attitude of government, and by lower forecasts of consumer need.

The Virginia Electric and Power Co. has suspended work on two nuclear units at Surry on the James River.

The Potomac Electric Power Co. has delayed the development schedule of a proposed two-unit nuclear plant at Douglas Point on the Potomac River in Charles County, Md.

The Baltimore Gas and Electric Co. has all but finally decided for the foreseeable future against building a nuclear plant at Perryman on the Chesapeak Bay, northeast of Baltimore.

The top executives of all three companies stressed, in separate interviews, that their hedging on nuclear power for the future was not caused by any lack of faith in it as an economical and safe source of energy.

Rather, they are concerned about what chairman C. Edward Utermohle Jr. of BG&E calls political - not nuclear - "risk," what president T. Justin Moore Jr. of Vepco calls "climate" for nuclear power plant construction and what chairman and president W. Reid Thompson of Pepco calls the "overall picture."

It is possible to deduce from the executives' remarks that nuclear foes, who lose virtually every battle, may be winning the war by sheer dogged persistence in one public hearing after another.

"We don't like to look at it from a 'winning or losing' standpoint," protested Bernard C. Trueschler, BG&E president. "We weigh the evidence available to us, analyze the economics and make a decision."

The economics of building and operating nuclear power plants are heavily influenced by actions of antinuclear organizations and individuals who intervene in the hearing process required to obtain nuclear plant licenses.

While the leaders of all three companies said they are firmly convinced that the nation's future energy wellbeing depends on nuclear power and coal - the current general policy of utility companies - they are willing to forestall further construction for the time being.

BG&E and Vepco already have a vast investment in and a great reliance on nuclear energy, but Pepco has made only a relatively small investment in its Douglas Point plans.

BG&E now is operating one nuclear unit at Calvert Cliffs in Calvert County on the Chesapeake Bay and is testing the second unit there.

The company said the nuclear unit saved consumers $50 million in 1975 through the use of nuclear power rather than other fuels. During the first 10 months of 1976, the nuclear unit produced more than 40 per cent of the electricity generated by the company and saved 400 million gallons of oil and $68 million in fuel charges, the company said.

While those are encouraging figures, the company noted that when it announced its Calvert Cliffs plans in 1967, it expected to have one nuclear unit operating in 1973 and the second operating in 1975, at a total cost of $300 million.

As it turned out, the first unit began operating in 1975 and the second unit isn't ready yet - and the total cost will be $750 million. Utilities figure that any plant they begin work on now will cost $1 billion for each nuclear unit.

There appears to be no precise method of measuring who or what causes each nuclear plant delay or cost overrun. Once there is delay, inflation becomes a major factor.Government regulators often have discovered errors in design or construction, manufacturers have made design improvements, legislators and regulators have tightened safety standards.

The Calvert Cliffs plant was fought every step of the way by the Chesapeake Environmental protection Association, an organization formed in 1969 for that specific purpose. CEPA still is watch-dogging every move BG&E makes and presently is arguing over the temperature of the water that the plant is disgorging back into the bay.

All parties agree that CEPA's years-long tenaciousness has been at least partly responsible for changes in state and national government standards and regulations for nuclear power plants and even landmark court rulings requiring that environmental considerations be part of the official licensing process.

The same thing has happened to Vepco, particularly over its plans to build a four-unit nuclear plant at North Anna in Louisa County. The North Anna Environmental Coalition, based in Charlottesville, began fullscale opposition in 1973 and continues to fight Vepco in public hearings and in court. Its impact has been significant.

Vepco built its first nuclear plant at Surry and during 1975 the two operating units there saved from $75 million to $125 million, depending on whether coal or oil was figured as the fuel that was replaced, the company said.

But Surry has been plagued with mechanical problems that have caused lengthy shut-downs and cut deeply into power production the company had counted on. Nevertheless, Surry produced 21 per cent of Vepco's generation in 1976, Vepco president Moore said.

He said the company hopes that when the first two units at North Anna start producing power - expected to be this year and next - nuclear energy will be generating about 50 per cent of Vepco's electricity.

Vepco plans had called for two more units at both North Anne and Surry, but now the Surry plans have been suspended.

Vepco's "seers into the future," headed by executive vice president Stanley Ragone, feel that six nuclear untis - two at Surry and four at North Anna - may prove to be enough.

Ragone explained that Vepco's forecasts of increased consumer demand have been scaled down drastically from the actual increases in the 1960s and early 1970s, as have been those of BG&E and Pepco. For the next decade, Vepco sees growth in usage of no more than 3 to 5 per cent a year.

This means that population growth is leveling off and, the leaders feel, company conservation messages are beginning to have an effect on consumers.

Ragone noted that because of the huge cost of building nuclear plants, they must be operated as much as possible to be economical. Therefore, the company wants nuclear power to supply only its constant electricity need, or between 50 and 60 per cent of its total electricity produced.

During the hours of heavy usage, and at the time of peak load, Vepco wants to use primarily coal, and ultimately the hydroelectric plant under construction in Bath County.

North Anna 1 and 2 originally were scheduled to start generating in 1974 and 1975 and the cost was figured in 1972 at about $1 billion for all four units. Now, it is expected that North Anna 1 will be started this year, the second unit next year and the third and fourth in 1983 and 1984. The cost has doubled.

Vepco said the doubling of the cost of its nuclear units and the delays in their construction were caused by a lack of construction manpower, changing government standards, unanticipated increased safety requirements, environmental and other interventions in public hearings, necessary repairs to the steam generator supports, Nuclear Regulatory Commission requirements that already constructed components be changed, labor disputes and the six-month halt in construction in 1974 because of the utility's financial problems.

Despite all, Vepco leaders said they feel they have until about 1980 to watch developments to decide finally whether to build more nuclear units. Pepco also is playing a watching and waiting game with its proposed Douglas Point plant while proceeding with the preliminary - and economically expendable - design work, environmental studies, site justification and the public hearing process, which began last summer.

BG&E, on the other hand, feels that if it is to meet customer needs it must start soon with another major plant - if not nuclear at Perryman, than coal somewhere else. Executives of the three companies agreed that the need for public hearings and government permits has increased for coal plants to the point that they now most allow about eight years to put one in operation. Nuclear plants take 10 years or so.

BG&E's chairman Utermohle is blunt about his company's worry over government attitude. With two openings now on the Nuclear Regulatory Commission and a third coming up in a few months, Utermohle said, "A great deal depends on the philosophies and attitudes of the people appointed to the Commission."