<PAGE>
 
                                                                    EXHIBIT 24.2

                               POWER OF ATTORNEY

     Each of the undersigned Directors of PG&E Gas Transmission, Northwest
Corporation (formerly Pacific Gas Transmission Company) hereby constitutes and
appoints LINDA Y.H. CHENG and MICHAEL C. DOTTEN, or either of them, as his
attorneys-in-fact with full power of substitution to sign and file with the
Securities and Exchange Commission in his capacity as such Director of said
corporation the Form 10-K Annual Report for the year ended December 31, 1998,
required by Section 13 or 15(d) of the Securities Exchange Act of 1934, and any
and all amendments and other filings or documents related thereto, and hereby
ratifies all that said attorneys-in-fact or either of them may do or cause to be
done by virtue hereof.

     This document may be signed in counterparts.

     IN WITNESS WHEREOF, we have executed this document this 24th day of March
1999.

                                   ________________________________  
                                            Thomas B. King           
                                                                     
                                   ________________________________  
                                             M. E. Rescoe             
                                                                     
                                   ________________________________  
                                         Bruce R. Worthington         
<PAGE>
 
                               POWER OF ATTORNEY

          THOMAS B. KING, the undersigned, President and Chief Operating Officer
of PG&E Gas Transmission, Northwest Corporation, hereby constitutes and appoints
LINDA Y.H. CHENG and MICHAEL C. DOTTEN, or either of them, as his attorneys-in-
fact with full power of substitution to sign and file with the Securities and
Exchange Commission in his capacity as President and Chief Operating Officer
(principal executive officer) of said corporation the Form 10-K Annual Report
for the year ended December 31, 1998, required by Section 13 or 15(d) of the
Securities Exchange Act of 1934, and any and all amendments and other filings or
documents related thereto, and hereby ratifies all that said attorneys-in-fact
or either of them may do or cause to be done by virtue hereof.

          IN WITNESS WHEREOF, I have executed this document this 24th day of
March 1999.

                                   ________________________________  
                                            Thomas B. King          
<PAGE>
 
                               POWER OF ATTORNEY
                                  
      STANLEY C. KARCZEWSKI, the undersigned, Vice President, Chief Financial
Officer and Controller, of PG&E Gas Transmission, Northwest Corporation, hereby
constitutes and appoints LINDA Y.H. CHENG and MICHAEL C. DOTTEN, or either of
them, as his attorneys-in-fact with full power of substitution to sign and file
with the Securities and Exchange Commission in his capacity as Vice President,
Finance, and Controller and Chief Financial Officer (principal financial and
accounting officer) of said corporation the Form 10-K Annual Report for the year
ended December 31, 1998, required by Section 13 or 15(d) of the Securities
Exchange Act of 1934 and any and all amendments and other filings or documents
related thereto, and hereby ratifies all that said attorneys in fact or either
of them may do or cause to be done by virtue hereof.

     IN WITNESS WHEREOF, I have executed this document this 24th day of March
1999.


                                   ________________________________  
                                        Stanley C. Karczewski