Rationing of electricity and fuel oil to retail businesses threw thousands of Virginians out of work today, but top executives of electric utilities and pipeline companies serving the state they had adequate supplies of both fuels.

In interviews during the last two days, executives of Virginia's two largest electric utilities strongly endorsed Gov. Mills E. Godwin's consevation order limiting the opening retail stores to 40 hours a week until Feb. 14. But they also said their power systems have the capacity and fuel to meet foreseeable demand even if the short-term rationing had not been imposed.

Officials of two oil pipeline companies that furnish 98 per cent of the heating oils sued in Virginia said they are puzzled by reports that shipments into the state are inadequate and running behind schedule.

H. B. McCauley, vice president of operations for Plantation Pipeline Co., said orders from the 31 companies it serves are being met on schedule. W. L. Nicoll, community relations manager for Colonial Pipeline Co., said oil shipments to Virginia were up 37 per cent in December, compared to 1975, and are being made on schedule.

Despite the reports of adequate fuel supplies Godwin and his adies have insisted in interviews that the rationing he ordered was necessary to protect reserves for the balance of the winter.

"We are not saying that there is a fuel oil shortage today>" Godwin said on Sunday, "but we have to take steps to prevent a draw down that would create a shortage later in February."

Godwin also said he is aware that the state's major electric utilities have adequate capacity to meet foreseable demand. He said he extended the order on business hours to include all-electrics companies because he feared that conversions to portable electric heaters by businesses deprived of natural gas or fuel oil could cause an electric energy crisis.

No state or utility official, howerver, was able to estimate the potential demand on electricty-generating capacity by such a conversion or say that it would pose any threat to generating capacity.

Godwin's rationing order issued on Saturday for a two-week period, is the most drastic energy action taken so far ny any state outside of the disaster areas of the Northeast and upper Midwest.

Godwin's aides said in interviews today that he issued the order after he and his closest advisers decided the state and national weather conditions required strict conservation of all fuels. The decision apparently was not based on precise estimates of energy supplies available for the near future.

The Virginia Employment Commission reported that 2,920 Virginians filed for unemployment beneftis today because they lost their jobs as a result of fuel curtailments. The VEC figures reflect only the number who have been laid off and file for relife. No estimate was available of the number of workers whose hours and pay have been reduced by the Godwin order, or for those who have been laid off but have not yet filled for benefits.

Before the emergency order, it was estimated that 30,000 to 40,000 Virginia workers had been idled by cold weather and natural gas shortages.

While they gave strong support of the governor's action as a conservation measure, electric utility executives supplied figures that raised serious question about the need for a short-term reduction of electricity usage.

Stanley Ragons, executive vice president of Virginia Electric and Power Co., the state's largest utility, said Vepco has been experiencing peak demand of 6,500 to 7,000 megawatts of poer during the period of extreme cold.

Even with two large generating units idle for repairs, Vepco currently has a generating capacity of about 8,400 megawatts, Ragone said. This leaves a reserve over peak demand of about 20 per cent to 25 per cent, exceeding the reserves recommended by state and federal uttility regulators.

John Vaughan, president of Appalachian Power Co., which serves the southwestern part of the state and is second in size to Vepco in Virginia, said he believes his utility has passed through its seasonal crisis. Peak demand on the Apco system this year was about 4,300 megawatts, compared with about 4,600 megawatts of capacity, he said.

"I think we have passed our crisis," he said. "The days are getting longer and the heating demand should gradually subside. We have been helped a little by the gas curtailments because industries that use gas have also cut their electrical demand when the cut back production."

On Sunday, the first day of business closings under the Godwin order, demand on electrical power was so light that the utilities did not bother to go through the complex process of calculating it. "We never measure weekend demand on a daily basis because it is minuscule compared with weekdays," a Vepco spokesman said.

Fuel oil supplies are much harder to calculate because it is an unregulated business and because oil is stored in countless location by distributors and users.

However, the statre's dire warning on Sunday that Virginia has only a "possible five to 10-day supply" of heating oil seems to have been based on a misunderstanding of the delivery system.

"I guess you could say that any time," Colonial Pipeline's Nicoll said. "We deliver fule in 10-day cycles - five days of gasoline and five days of oil. At the end of one oil delivery, you have five days until the next one."