Virginia Electric and Power Co. yesterday proposed changes in the way it bills customers for electricity - changes that would boost the fuel cost portion of a monthly electric bill from an average of $2.83 to $3.25 for customers using 1,000 kilowatt hours.

Vepco spokesman Doug Cochran said the average residential customer uses 800 or 900 kilowatt hours a month rather than 1,000 a figure the company cited in an announcement. He said the increase would be even higher if the company did not plan to open a second nuclear generating unit at its North Anna facility in July.

The proposed fuel costs, which must be approved by the State Corporation Commission before it can be effective will be divided into two parts: $4 a month for that 1,000-kilowatt hour customer until the North Anna nuclear unit opens, and $2.50 a month after that, for the $3.25 yearly average.

Currently Vepco's fuel costs vary from month to month according to complex formula that allows the company automatically to pass through to customers the costs it pays for crude oil and nuclear fuel.

Early this year the state legislative passed a new law requiring that fuel cost be stabilized to set amount so that customers could be more contain of what their electric bills might amount to each month.

Vepco has three nuclear units operation and is planning many more. While there has been public opposition to nuclear power in the state the company has argued that nuclear is cheaper than coal or oil and therefore necessary.

The company's request for an increase in the fuel rate passthrough yesterday comes as the SCC is considering a larger request for 25 percent increase in electric rates.