<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 Paula E. Pyron and Linda Y.H. Cheng, 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, 1999,
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 23rd day of March,
2000.

                            /s/ Thomas B. King
                      ----------------------------------
                                Thomas B. King


                            /s/ Peter A. Darbee
                      ----------------------------------
                                Peter A. Darbee


                         /s/ Bruce R. Worthington
                      ----------------------------------
                             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
Paula E. Pyron and Linda Y.H. Cheng, 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, 1999, 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 23rd day of March,
2000.

                                                       /s/ Thomas B. King
                                                  ------------------------------
                                                           Thomas B. King
<PAGE>

                               POWER OF ATTORNEY


     JEFFREY J. McPARLAND, the undersigned, Senior Vice President, Chief
Financial Officer and Treasurer, of PG&E Gas Transmission, Northwest
Corporation, hereby constitutes and appoints Paula E. Pyron and Linda Y.H.
Cheng, 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 Senior Vice President, Chief Financial Officer and Treasurer
(principal financial and accounting officer) of said corporation the Form 10-K
Annual Report for the year ended December 31, 1999, 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 23rd day of March,
2000.

                                                  /s/ Jeffrey J. McParland
                                             -----------------------------------
                                                     Jeffrey J. McParland