<PAGE>
 
                        HOUSTON INDUSTRIES INCORPORATED

                               Power of Attorney

                     (Automatic Common Exchange Securities)


          WHEREAS, HOUSTON INDUSTRIES INCORPORATED, a Texas corporation (the
"Company"), intends to file with the Securities and Exchange Commission (the
"Commission") under the Securities Act of 1933, as amended (the "Act"), one or
more Registration Statements, each on Form S-3 (the "Registration Statement"),
including in each instance any prospectus included therein (a "Prospectus"),
with such amendments (including pre-effective and post-effective amendments) to
each such Registration Statement and any supplement or supplements to the
Prospectus as may be necessary or appropriate, together with any and all
exhibits and other documents related to each such Registration Statement or
Prospectus, in connection with the registration of up to 23,000,000 Automatic
Common Exchange Securities due 2000 (subject to exchange into shares of common
stock of Time Warner Inc.).

          NOW, THEREFORE, the undersigned in his capacity as a director or
officer or both, as the case may be, of the Company, does hereby appoint 
Don D. Jordan, Hugh Rice Kelly and Stephen W. Naeve, and each of them severally,
his true and lawful attorney or attorneys-in-fact, with power to act with or
without the others and with full power of substitution and resubstitution, to
execute in his name, place and stead, in his capacity as a director or officer
or both, as the case may be, of the Company, each such Registration Statement
referred to above, and any and all amendments (including pre-effective and post-
effective amendments) thereto, and any supplements to the Prospectus as said
attorneys-in-fact or any of them shall deem necessary or appropriate, together
with all instruments necessary or incidental in connection therewith, to file
the same or cause the same to be filed with the Commission, and to appear before
the Commission in connection with any matter relating thereto. Each of said
attorneys-in-fact shall have full power and authority to do and perform in the
name and on behalf of the undersigned, in any and all capacities, every act
whatsoever necessary or desirable to be done, as fully and for all intents and
purposes as the undersigned might or could do in person, the undersigned hereby
ratifying and approving the acts that said attorneys-in-fact and each of them
may lawfully do or cause to be done by virtue hereof.

          IN WITNESS WHEREOF, the undersigned has executed this instrument this
24th day of June, 1997.


                                    /s/ DON D. JORDAN
                                    -----------------------------
                                    Don D. Jordan
<PAGE>
 
                        HOUSTON INDUSTRIES INCORPORATED

                               Power of Attorney

                    (Automatic Common Exchange Securities)


          WHEREAS, HOUSTON INDUSTRIES INCORPORATED, a Texas corporation (the
"Company"), intends to file with the Securities and Exchange Commission (the
"Commission") under the Securities Act of 1933, as amended (the "Act"), one or
more Registration Statements, each on Form S-3 (the "Registration Statement"),
including in each instance any prospectus included therein (a "Prospectus"),
with such amendments (including pre-effective and post-effective amendments) to
each such Registration Statement and any supplement or supplements to the
Prospectus as may be necessary or appropriate, together with any and all
exhibits and other documents related to each such Registration Statement or
Prospectus, in connection with the registration of up to 23,000,000 Automatic
Common Exchange Securities due 2000 (subject to exchange into shares of common
stock of Time Warner Inc.).

          NOW, THEREFORE, the undersigned in his capacity as a director or
officer or both, as the case may be, of the Company, does hereby appoint 
Don D. Jordan, Hugh Rice Kelly and Stephen W. Naeve, and each of them severally,
his true and lawful attorney or attorneys-in-fact, with power to act with or
without the others and with full power of substitution and resubstitution, to
execute in his name, place and stead, in his capacity as a director or officer
or both, as the case may be, of the Company, each such Registration Statement
referred to above, and any and all amendments (including pre-effective and post-
effective amendments) thereto, and any supplements to the Prospectus as said
attorneys-in-fact or any of them shall deem necessary or appropriate, together
with all instruments necessary or incidental in connection therewith, to file
the same or cause the same to be filed with the Commission, and to appear before
the Commission in connection with any matter relating thereto. Each of said
attorneys-in-fact shall have full power and authority to do and perform in the
name and on behalf of the undersigned, in any and all capacities, every act
whatsoever necessary or desirable to be done, as fully and for all intents and
purposes as the undersigned might or could do in person, the undersigned hereby
ratifying and approving the acts that said attorneys-in-fact and each of them
may lawfully do or cause to be done by virtue hereof.

          IN WITNESS WHEREOF, the undersigned has executed this instrument this
25th day of June, 1997.


                                    /s/ STEPHEN W. NAEVE
                                    -----------------------------
                                    Stephen W. Naeve
<PAGE>
 
                        HOUSTON INDUSTRIES INCORPORATED

                               Power of Attorney

                    (Automatic Common Exchange Securities)


          WHEREAS, HOUSTON INDUSTRIES INCORPORATED, a Texas corporation (the
"Company"), intends to file with the Securities and Exchange Commission (the
"Commission") under the Securities Act of 1933, as amended (the "Act"), one or
more Registration Statements, each on Form S-3 (the "Registration Statement"),
including in each instance any prospectus included therein (a "Prospectus"),
with such amendments (including pre-effective and post-effective amendments) to
each such Registration Statement and any supplement or supplements to the
Prospectus as may be necessary or appropriate, together with any and all
exhibits and other documents related to each such Registration Statement or
Prospectus, in connection with the registration of up to 23,000,000 Automatic
Common Exchange Securities due 2000 (subject to exchange into shares of common
stock of Time Warner Inc.).

          NOW, THEREFORE, the undersigned in his capacity as a director or
officer or both, as the case may be, of the Company, does hereby appoint 
Don D. Jordan, Hugh Rice Kelly and Stephen W. Naeve, and each of them severally,
his true and lawful attorney or attorneys-in-fact, with power to act with or
without the others and with full power of substitution and resubstitution, to
execute in his name, place and stead, in his capacity as a director or officer
or both, as the case may be, of the Company, each such Registration Statement
referred to above, and any and all amendments (including pre-effective and post-
effective amendments) thereto, and any supplements to the Prospectus as said
attorneys-in-fact or any of them shall deem necessary or appropriate, together
with all instruments necessary or incidental in connection therewith, to file
the same or cause the same to be filed with the Commission, and to appear before
the Commission in connection with any matter relating thereto. Each of said
attorneys-in-fact shall have full power and authority to do and perform in the
name and on behalf of the undersigned, in any and all capacities, every act
whatsoever necessary or desirable to be done, as fully and for all intents and
purposes as the undersigned might or could do in person, the undersigned hereby
ratifying and approving the acts that said attorneys-in-fact and each of them
may lawfully do or cause to be done by virtue hereof.

          IN WITNESS WHEREOF, the undersigned has executed this instrument this
25th day of June, 1997.


                                    /s/ MARY P. RICCIARDELLO
                                    -----------------------------
                                    Mary P. Ricciardello
<PAGE>
 
                        HOUSTON INDUSTRIES INCORPORATED

                               Power of Attorney

                    (Automatic Common Exchange Securities)


          WHEREAS, HOUSTON INDUSTRIES INCORPORATED, a Texas corporation (the
"Company"), intends to file with the Securities and Exchange Commission (the
"Commission") under the Securities Act of 1933, as amended (the "Act"), one or
more Registration Statements, each on Form S-3 (the "Registration Statement"),
including in each instance any prospectus included therein (a "Prospectus"),
with such amendments (including pre-effective and post-effective amendments) to
each such Registration Statement and any supplement or supplements to the
Prospectus as may be necessary or appropriate, together with any and all
exhibits and other documents related to each such Registration Statement or
Prospectus, in connection with the registration of up to 23,000,000 Automatic
Common Exchange Securities due 2000 (subject to exchange into shares of common
stock of Time Warner Inc.).

          NOW, THEREFORE, the undersigned in his capacity as a director or
officer or both, as the case may be, of the Company, does hereby appoint 
Don D. Jordan, Hugh Rice Kelly and Stephen W. Naeve, and each of them severally,
his true and lawful attorney or attorneys-in-fact, with power to act with or
without the others and with full power of substitution and resubstitution, to
execute in his name, place and stead, in his capacity as a director or officer
or both, as the case may be, of the Company, each such Registration Statement
referred to above, and any and all amendments (including pre-effective and post-
effective amendments) thereto, and any supplements to the Prospectus as said
attorneys-in-fact or any of them shall deem necessary or appropriate, together
with all instruments necessary or incidental in connection therewith, to file
the same or cause the same to be filed with the Commission, and to appear before
the Commission in connection with any matter relating thereto. Each of said
attorneys-in-fact shall have full power and authority to do and perform in the
name and on behalf of the undersigned, in any and all capacities, every act
whatsoever necessary or desirable to be done, as fully and for all intents and
purposes as the undersigned might or could do in person, the undersigned hereby
ratifying and approving the acts that said attorneys-in-fact and each of them
may lawfully do or cause to be done by virtue hereof.

          IN WITNESS WHEREOF, the undersigned has executed this instrument this
30th day of June, 1997.


                                    /s/ MILTON CARROLL
                                    -----------------------------
                                    Milton Carroll
<PAGE>
 
                        HOUSTON INDUSTRIES INCORPORATED

                               Power of Attorney

                    (Automatic Common Exchange Securities)


          WHEREAS, HOUSTON INDUSTRIES INCORPORATED, a Texas corporation (the
"Company"), intends to file with the Securities and Exchange Commission (the
"Commission") under the Securities Act of 1933, as amended (the "Act"), one or
more Registration Statements, each on Form S-3 (the "Registration Statement"),
including in each instance any prospectus included therein (a "Prospectus"),
with such amendments (including pre-effective and post-effective amendments) to
each such Registration Statement and any supplement or supplements to the
Prospectus as may be necessary or appropriate, together with any and all
exhibits and other documents related to each such Registration Statement or
Prospectus, in connection with the registration of up to 23,000,000 Automatic
Common Exchange Securities due 2000 (subject to exchange into shares of common
stock of Time Warner Inc.).

          NOW, THEREFORE, the undersigned in his capacity as a director or
officer or both, as the case may be, of the Company, does hereby appoint 
Don D. Jordan, Hugh Rice Kelly and Stephen W. Naeve, and each of them severally,
his true and lawful attorney or attorneys-in-fact, with power to act with or
without the others and with full power of substitution and resubstitution, to
execute in his name, place and stead, in his capacity as a director or officer
or both, as the case may be, of the Company, each such Registration Statement
referred to above, and any and all amendments (including pre-effective and post-
effective amendments) thereto, and any supplements to the Prospectus as said
attorneys-in-fact or any of them shall deem necessary or appropriate, together
with all instruments necessary or incidental in connection therewith, to file
the same or cause the same to be filed with the Commission, and to appear before
the Commission in connection with any matter relating thereto. Each of said
attorneys-in-fact shall have full power and authority to do and perform in the
name and on behalf of the undersigned, in any and all capacities, every act
whatsoever necessary or desirable to be done, as fully and for all intents and
purposes as the undersigned might or could do in person, the undersigned hereby
ratifying and approving the acts that said attorneys-in-fact and each of them
may lawfully do or cause to be done by virtue hereof.

          IN WITNESS WHEREOF, the undersigned has executed this instrument this
25th day of June, 1997.


                                    /s/ JOHN T. CATER
                                    -----------------------------
                                    John T. Cater
<PAGE>
 
                        HOUSTON INDUSTRIES INCORPORATED

                               Power of Attorney

                    (Automatic Common Exchange Securities)


          WHEREAS, HOUSTON INDUSTRIES INCORPORATED, a Texas corporation (the
"Company"), intends to file with the Securities and Exchange Commission (the
"Commission") under the Securities Act of 1933, as amended (the "Act"), one or
more Registration Statements, each on Form S-3 (the "Registration Statement"),
including in each instance any prospectus included therein (a "Prospectus"),
with such amendments (including pre-effective and post-effective amendments) to
each such Registration Statement and any supplement or supplements to the
Prospectus as may be necessary or appropriate, together with any and all
exhibits and other documents related to each such Registration Statement or
Prospectus, in connection with the registration of up to 23,000,000 Automatic
Common Exchange Securities due 2000 (subject to exchange into shares of common
stock of Time Warner Inc.).

          NOW, THEREFORE, the undersigned in his capacity as a director or
officer or both, as the case may be, of the Company, does hereby appoint 
Don D. Jordan, Hugh Rice Kelly and Stephen W. Naeve, and each of them severally,
his true and lawful attorney or attorneys-in-fact, with power to act with or
without the others and with full power of substitution and resubstitution, to
execute in his name, place and stead, in his capacity as a director or officer
or both, as the case may be, of the Company, each such Registration Statement
referred to above, and any and all amendments (including pre-effective and post-
effective amendments) thereto, and any supplements to the Prospectus as said
attorneys-in-fact or any of them shall deem necessary or appropriate, together
with all instruments necessary or incidental in connection therewith, to file
the same or cause the same to be filed with the Commission, and to appear before
the Commission in connection with any matter relating thereto. Each of said
attorneys-in-fact shall have full power and authority to do and perform in the
name and on behalf of the undersigned, in any and all capacities, every act
whatsoever necessary or desirable to be done, as fully and for all intents and
purposes as the undersigned might or could do in person, the undersigned hereby
ratifying and approving the acts that said attorneys-in-fact and each of them
may lawfully do or cause to be done by virtue hereof.

          IN WITNESS WHEREOF, the undersigned has executed this instrument this
24th day of June, 1997.


                                    /s/ ROBERT J. CRUIKSHANK
                                    -----------------------------
                                    Robert J. Cruikshank
<PAGE>
 
                        HOUSTON INDUSTRIES INCORPORATED

                               Power of Attorney

                    (Automatic Common Exchange Securities)


          WHEREAS, HOUSTON INDUSTRIES INCORPORATED, a Texas corporation (the
"Company"), intends to file with the Securities and Exchange Commission (the
"Commission") under the Securities Act of 1933, as amended (the "Act"), one or
more Registration Statements, each on Form S-3 (the "Registration Statement"),
including in each instance any prospectus included therein (a "Prospectus"),
with such amendments (including pre-effective and post-effective amendments) to
each such Registration Statement and any supplement or supplements to the
Prospectus as may be necessary or appropriate, together with any and all
exhibits and other documents related to each such Registration Statement or
Prospectus, in connection with the registration of up to 23,000,000 Automatic
Common Exchange Securities due 2000 (subject to exchange into shares of common
stock of Time Warner Inc.).

          NOW, THEREFORE, the undersigned in his capacity as a director or
officer or both, as the case may be, of the Company, does hereby appoint 
Don D. Jordan, Hugh Rice Kelly and Stephen W. Naeve, and each of them severally,
his true and lawful attorney or attorneys-in-fact, with power to act with or
without the others and with full power of substitution and resubstitution, to
execute in his name, place and stead, in his capacity as a director or officer
or both, as the case may be, of the Company, each such Registration Statement
referred to above, and any and all amendments (including pre-effective and post-
effective amendments) thereto, and any supplements to the Prospectus as said
attorneys-in-fact or any of them shall deem necessary or appropriate, together
with all instruments necessary or incidental in connection therewith, to file
the same or cause the same to be filed with the Commission, and to appear before
the Commission in connection with any matter relating thereto. Each of said
attorneys-in-fact shall have full power and authority to do and perform in the
name and on behalf of the undersigned, in any and all capacities, every act
whatsoever necessary or desirable to be done, as fully and for all intents and
purposes as the undersigned might or could do in person, the undersigned hereby
ratifying and approving the acts that said attorneys-in-fact and each of them
may lawfully do or cause to be done by virtue hereof.

          IN WITNESS WHEREOF, the undersigned has executed this instrument this
24th day of June, 1997.


                                    /s/ LINNET F. DEILY
                                    -----------------------------
                                    Linnet F. Deily
<PAGE>
 
                        HOUSTON INDUSTRIES INCORPORATED

                               Power of Attorney

                    (Automatic Common Exchange Securities)


          WHEREAS, HOUSTON INDUSTRIES INCORPORATED, a Texas corporation (the
"Company"), intends to file with the Securities and Exchange Commission (the
"Commission") under the Securities Act of 1933, as amended (the "Act"), one or
more Registration Statements, each on Form S-3 (the "Registration Statement"),
including in each instance any prospectus included therein (a "Prospectus"),
with such amendments (including pre-effective and post-effective amendments) to
each such Registration Statement and any supplement or supplements to the
Prospectus as may be necessary or appropriate, together with any and all
exhibits and other documents related to each such Registration Statement or
Prospectus, in connection with the registration of up to 23,000,000 Automatic
Common Exchange Securities due 2000 (subject to exchange into shares of common
stock of Time Warner Inc.).

          NOW, THEREFORE, the undersigned in his capacity as a director or
officer or both, as the case may be, of the Company, does hereby appoint 
Don D. Jordan, Hugh Rice Kelly and Stephen W. Naeve, and each of them severally,
his true and lawful attorney or attorneys-in-fact, with power to act with or
without the others and with full power of substitution and resubstitution, to
execute in his name, place and stead, in his capacity as a director or officer
or both, as the case may be, of the Company, each such Registration Statement
referred to above, and any and all amendments (including pre-effective and post-
effective amendments) thereto, and any supplements to the Prospectus as said
attorneys-in-fact or any of them shall deem necessary or appropriate, together
with all instruments necessary or incidental in connection therewith, to file
the same or cause the same to be filed with the Commission, and to appear before
the Commission in connection with any matter relating thereto. Each of said
attorneys-in-fact shall have full power and authority to do and perform in the
name and on behalf of the undersigned, in any and all capacities, every act
whatsoever necessary or desirable to be done, as fully and for all intents and
purposes as the undersigned might or could do in person, the undersigned hereby
ratifying and approving the acts that said attorneys-in-fact and each of them
may lawfully do or cause to be done by virtue hereof.

          IN WITNESS WHEREOF, the undersigned has executed this instrument this
24th day of June, 1997.


                                    /s/ LEE W. HOGAN
                                    -----------------------------
                                    Lee W. Hogan
<PAGE>
 
                        HOUSTON INDUSTRIES INCORPORATED

                               Power of Attorney

                    (Automatic Common Exchange Securities)


          WHEREAS, HOUSTON INDUSTRIES INCORPORATED, a Texas corporation (the
"Company"), intends to file with the Securities and Exchange Commission (the
"Commission") under the Securities Act of 1933, as amended (the "Act"), one or
more Registration Statements, each on Form S-3 (the "Registration Statement"),
including in each instance any prospectus included therein (a "Prospectus"),
with such amendments (including pre-effective and post-effective amendments) to
each such Registration Statement and any supplement or supplements to the
Prospectus as may be necessary or appropriate, together with any and all
exhibits and other documents related to each such Registration Statement or
Prospectus, in connection with the registration of up to 23,000,000 Automatic
Common Exchange Securities due 2000 (subject to exchange into shares of common
stock of Time Warner Inc.).

          NOW, THEREFORE, the undersigned in his capacity as a director or
officer or both, as the case may be, of the Company, does hereby appoint 
Don D. Jordan, Hugh Rice Kelly and Stephen W. Naeve, and each of them severally,
his true and lawful attorney or attorneys-in-fact, with power to act with or
without the others and with full power of substitution and resubstitution, to
execute in his name, place and stead, in his capacity as a director or officer
or both, as the case may be, of the Company, each such Registration Statement
referred to above, and any and all amendments (including pre-effective and post-
effective amendments) thereto, and any supplements to the Prospectus as said
attorneys-in-fact or any of them shall deem necessary or appropriate, together
with all instruments necessary or incidental in connection therewith, to file
the same or cause the same to be filed with the Commission, and to appear before
the Commission in connection with any matter relating thereto. Each of said
attorneys-in-fact shall have full power and authority to do and perform in the
name and on behalf of the undersigned, in any and all capacities, every act
whatsoever necessary or desirable to be done, as fully and for all intents and
purposes as the undersigned might or could do in person, the undersigned hereby
ratifying and approving the acts that said attorneys-in-fact and each of them
may lawfully do or cause to be done by virtue hereof.

          IN WITNESS WHEREOF, the undersigned has executed this instrument this
30th day of June, 1997.


                                    /s/ R. STEVE LETBETTER
                                    -----------------------------
                                    R. Steve Letbetter
<PAGE>
 
                        HOUSTON INDUSTRIES INCORPORATED

                               Power of Attorney

                    (Automatic Common Exchange Securities)


          WHEREAS, HOUSTON INDUSTRIES INCORPORATED, a Texas corporation (the
"Company"), intends to file with the Securities and Exchange Commission (the
"Commission") under the Securities Act of 1933, as amended (the "Act"), one or
more Registration Statements, each on Form S-3 (the "Registration Statement"),
including in each instance any prospectus included therein (a "Prospectus"),
with such amendments (including pre-effective and post-effective amendments) to
each such Registration Statement and any supplement or supplements to the
Prospectus as may be necessary or appropriate, together with any and all
exhibits and other documents related to each such Registration Statement or
Prospectus, in connection with the registration of up to 23,000,000 Automatic
Common Exchange Securities due 2000 (subject to exchange into shares of common
stock of Time Warner Inc.).

          NOW, THEREFORE, the undersigned in his capacity as a director or
officer or both, as the case may be, of the Company, does hereby appoint 
Don D. Jordan, Hugh Rice Kelly and Stephen W. Naeve, and each of them severally,
his true and lawful attorney or attorneys-in-fact, with power to act with or
without the others and with full power of substitution and resubstitution, to
execute in his name, place and stead, in his capacity as a director or officer
or both, as the case may be, of the Company, each such Registration Statement
referred to above, and any and all amendments (including pre-effective and post-
effective amendments) thereto, and any supplements to the Prospectus as said
attorneys-in-fact or any of them shall deem necessary or appropriate, together
with all instruments necessary or incidental in connection therewith, to file
the same or cause the same to be filed with the Commission, and to appear before
the Commission in connection with any matter relating thereto. Each of said
attorneys-in-fact shall have full power and authority to do and perform in the
name and on behalf of the undersigned, in any and all capacities, every act
whatsoever necessary or desirable to be done, as fully and for all intents and
purposes as the undersigned might or could do in person, the undersigned hereby
ratifying and approving the acts that said attorneys-in-fact and each of them
may lawfully do or cause to be done by virtue hereof.

          IN WITNESS WHEREOF, the undersigned has executed this instrument this
24th day of June, 1997.


                                    /s/ ALEXANDER F. SCHILT
                                    -----------------------------
                                    Alexander F. Schilt
<PAGE>
 
                        HOUSTON INDUSTRIES INCORPORATED

                               Power of Attorney

                    (Automatic Common Exchange Securities)


          WHEREAS, HOUSTON INDUSTRIES INCORPORATED, a Texas corporation (the
"Company"), intends to file with the Securities and Exchange Commission (the
"Commission") under the Securities Act of 1933, as amended (the "Act"), one or
more Registration Statements, each on Form S-3 (the "Registration Statement"),
including in each instance any prospectus included therein (a "Prospectus"),
with such amendments (including pre-effective and post-effective amendments) to
each such Registration Statement and any supplement or supplements to the
Prospectus as may be necessary or appropriate, together with any and all
exhibits and other documents related to each such Registration Statement or
Prospectus, in connection with the registration of up to 23,000,000 Automatic
Common Exchange Securities due 2000 (subject to exchange into shares of common
stock of Time Warner Inc.).

          NOW, THEREFORE, the undersigned in his capacity as a director or
officer or both, as the case may be, of the Company, does hereby appoint 
Don D. Jordan, Hugh Rice Kelly and Stephen W. Naeve, and each of them severally,
his true and lawful attorney or attorneys-in-fact, with power to act with or
without the others and with full power of substitution and resubstitution, to
execute in his name, place and stead, in his capacity as a director or officer
or both, as the case may be, of the Company, each such Registration Statement
referred to above, and any and all amendments (including pre-effective and post-
effective amendments) thereto, and any supplements to the Prospectus as said
attorneys-in-fact or any of them shall deem necessary or appropriate, together
with all instruments necessary or incidental in connection therewith, to file
the same or cause the same to be filed with the Commission, and to appear before
the Commission in connection with any matter relating thereto. Each of said
attorneys-in-fact shall have full power and authority to do and perform in the
name and on behalf of the undersigned, in any and all capacities, every act
whatsoever necessary or desirable to be done, as fully and for all intents and
purposes as the undersigned might or could do in person, the undersigned hereby
ratifying and approving the acts that said attorneys-in-fact and each of them
may lawfully do or cause to be done by virtue hereof.

          IN WITNESS WHEREOF, the undersigned has executed this instrument this
25th day of June, 1997.


                                    /s/ BERTRAM WOLFE
                                    -----------------------------
                                    Bertram Wolfe