<PAGE>

                                                                    Exhibit 12-A

                        Delmarva Power & Light Company

                      Ratio of Earnings to Fixed Charges
                      ----------------------------------
                            (Dollars in Thousands)

<TABLE>
<CAPTION>
                                         12 Months
                                           Ended
                                         September 30,                         Year Ended December 31,
                                                        -------------------------------------------------------------------
                                           2000            1999           1998          1997          1996          1995
                                        -----------     -----------   -----------    ---------    ----------     ----------
<S>                                     <C>             <C>           <C>            <C>          <C>            <C>
Income before extraordinary item        $  125,772      $   142,179   $   112,410    $ 105,709    $  116,187     $ 117,488
                                        -----------     -----------   -----------    ---------    ----------     ----------

Income taxes                                82,325           95,321        72,276       72,155        78,340        75,540
                                        -----------     -----------   -----------    ---------    ----------     ----------
Fixed charges:
     Interest on long-term debt
        including amortization of
        discount, premium and
        expense                             77,289           77,790        81,132       78,350        69,329        65,572
     Other interest                          6,215            6,117         9,328       12,835        12,516        10,353
     Preferred dividend require-
        ments of a subsidiary
        trust                                5,687            5,687         5,688        5,687         1,390             -
                                        -----------     -----------   -----------    ---------    ----------     ----------
        Total fixed charges                 89,191           89,594        96,148       96,872        83,235        75,925
                                        -----------     -----------   -----------    ---------    ----------     ----------

Nonutility capitalized interest                  -                -             -         (208)         (311)         (304)
                                        -----------     -----------   -----------    ---------     ---------     ---------


Earnings before extraordinary
     item, income taxes, and
     fixed charges                      $  297,288      $   327,094   $   280,834    $ 274,528    $  277,451     $ 268,649
                                        ==========      ===========   ===========    =========    ==========     ==========
Ratio of earnings to fixed charges            3.33             3.65          2.92         2.83          3.33          3.54
</TABLE>

For purposes of computing the ratio, earnings are income before extraordinary
item plus income taxes and fixed charges, less nonutility capitalized interest.
Fixed charges consist of interest on long- and short-term debt, amortization of
debt discount, premium, and expense, dividends on preferred securities of a
subsidiary trust, plus the estimated interest component of rentals.