The Virginia Electric & Power Company and Old Dominion Electric Cooperative reported yesterday that they have reached an agreement that will result in revenues of approximately $265 million for Vepco.

Under the agreement, the Richmond power supply cooperative will buy portions of Vepco's North Anna Nuclear Power Station that are expected to provide about 20 percent of Old Dominion's needs. Old Dominion is responsible for obtaining power for its 15 member cooperatives.

The agreement was the outcome of nearly eight years of discussions between the two entities. Under its terms, Old Dominion will buy 12 1/2 percent of North Anna Units 1 and 2; 12 1/2 percent of the nuclear fuel and common facilities at the power station, and a portion of spare parts, inventory and other support facilities.

The cooperative will also be responsible for 12 1/2 percent of all future expenditures on the nuclear facilities and for a share of the operating costs. Vepco expects to receive about $208 million of the total $265 million at the closing, which is expected to be in mid-1983. The money will be used to meet future financing requirements, Vepco President William W. Berry said.

The sales agreement essentially replaces short-term electricity purchases by Old Dominion with a longer-term arrangement. The cooperative now buys approximately 8 percent of the production from those facilities. In the future that figure is expected to rise to 12 1/2 percent. In the interim, Old Dominion will use only what it needs and sell the difference between that figure and the 12 1/2 percent back to Vepco.

The cooperative will also continue to purchase the remainder of its power requirements from Vepco, Vepco officials said.

The agreement must receive approval from five regulatory agencies before it goes into effect.