WASHINGTON — Dominion Virginia Power is seeking a reduction in its customer bills, but not because the utility is being generous.

The utility has filed for a reduction in its fuel charge, which makes up about 20 percent of a customer’s bill. Dominion Virginia Power is not allowed to make a profit off the fuel charge, and with cheaper natural gas and oil prices, it would be passing those savings on to customers.

Dominion says fuel costs are also lower because of generating efficiency and milder weather, which has reduced demand.

If the Virginia State Corporation Commission approves the reduction in the fuel charge, the new rate would take effect July 1.

Dominion Virginia has also filed for an increase in another charge on customers’ monthly bills, seeking regulatory approval for a 0.3 percent increase in its transmission rate charge. If that is approved, it would take effect Sept. 1.

The reduction in the fuel charge would cut a typical residential customer’s monthly bill by $4.35. The increased transmission charge would add about 30 cents to a typical residential bill.

Dominion Virginia Power is not currently seeking an increase in its base rates, which make up about 60 percent of a residential bill.