<PAGE>

                                                                 CLASS A WARRANT

THIS WARRANT AND THE SECURITIES ISSUABLE UPON THE EXERCISE HEREOF ARE NOT
TRANSFERABLE EXCEPT AS SET FORTH IN THE STOCKHOLDERS AGREEMENT DATED AS OF
JANUARY 6, 2000 BY AND AMONG THE COMPANY AND CERTAIN STOCKHOLDERS NAMED THEREIN,
AS AMENDED. THIS WARRANT AND THE SECURITIES ISSUABLE UPON THE EXERCISE HEREOF
HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933, AS AMENDED, OR THE
SECURITIES LAWS OF ANY STATE OR OTHER JURISDICTION. SUCH SECURITIES MAY NOT BE
SOLD, ASSIGNED OR OTHERWISE TRANSFERRED EXCEPT UPON SUCH REGISTRATION OR UPON
DELIVERY TO THE COMPANY OF AN OPINION OF COUNSEL REASONABLY SATISFACTORY TO THE
COMPANY STATING THAT SUCH SALE, ASSIGNMENT OR TRANSFER IS EXEMPT FROM
REGISTRATION UNDER SUCH ACT AND LAWS.

                                   TNPC, INC.

                           WARRANT FOR THE PURCHASE OF
                                    SHARES OF
                             NON-VOTING COMMON STOCK



No. ___                                                      ____________Shares


         BY THIS WARRANT (this "WARRANT"), TNPC, Inc., a Delaware corporation
(the "COMPANY"), certifies that, for good and valuable consideration, the
receipt and sufficiency of which are hereby acknowledged, __________ (along with
its registered permitted assigns, the "HOLDER"), is entitled to subscribe for
and purchase from the Company, subject to the terms and conditions set forth
herein, _____________ (subject to adjustment as set forth herein) fully paid and
non-assessable shares (the "SHARES") of the Company's Non-Voting Common Stock
(as defined herein), at a price per share equal to $10.00 per Share (the
"EXERCISE PRICE"), subject to adjustment as set forth herein.

         1.       DEFINITIONS. Unless the context otherwise requires, when used
herein the following terms shall have the meaning indicated.

         "BOARD" means the Board of Directors of the Company.

         "BUSINESS DAY" means any day other than a Saturday, Sunday or a day on
         which banks are authorized or required by law to close in the city of
         Houston, Texas.

         "CAPITAL STOCK" means (i) with respect to any Person that is a
         corporation, any and all shares, interests, participations or other
         equivalents (however designated) of capital or capital stock of such
         Person and (ii) with respect to any Person that is not a corporation,
         any and all partnership or other equity interests of such Person.


                                       1
<PAGE>
         "COMMON STOCK" means both the Company's Voting Common Stock and
         Non-Voting Common Stock.

         "CONVERTIBLE SECURITIES" shall mean evidences of indebtedness, shares
         of stock or other securities which are convertible into or
         exchangeable, with or without payment of additional consideration in
         cash or property, for shares of Common Stock, either immediately or
         upon the occurrence of a specified date or a specified event.

         "EXERCISE NOTICE" has the meaning set forth in Section 2(a).

         "EXERCISE PRICE" means the initial Exercise Price specified in the
         first paragraph of this Warrant, as adjusted from time to time as
         provided in SECTION 7.

         "EXPIRATION TIME" has the meaning set forth in Section 2(a).

         "FAIR MARKET VALUE" means, at or prior to an Initial Public Offering or
         if the Common Stock is otherwise not traded in such manner that the
         quotations referred to below are available for the period required
         hereunder, the fair value per share of the Common Stock as determined
         by the Special Committee in good faith and irrespective of any
         accounting treatment. After the occurrence of an Initial Public
         Offering, Fair Market Value shall mean, in the event the Common Stock
         is publicly traded, the Closing Price on the day in question if such
         day is a Trading Day, and if not, on the previous Trading Day. The
         "Closing Price" for each Trading Day shall be the last reported sale
         price regular way or, in case no such reported sale takes place on such
         day, the average of the last closing bid and asked prices regular way,
         in either case on the principal national securities exchange on which
         the Common Stock is listed or admitted to trading, or if not listed or
         admitted to trading on any national securities exchange, the closing
         sale price for such day reported by The Nasdaq Stock Market, if the
         Common Stock is traded over the counter and quoted in the National
         Market System, or if the Common Stock is so traded, but not so quoted,
         the average of the closing reported bid and asked prices of the Common
         Stock as reported by Nasdaq or any comparable system or, if the Common
         Stock is not listed on Nasdaq or any comparable system, the average of
         the closing bid and asked prices as furnished by two members of the
         National Association of Securities Dealers, Inc. selected from time to
         time by the Company for that purpose. "Trading Day" means a day on
         which the principal exchange or quotation system on which the Common
         Stock is then traded is open for trading.

         "INITIAL EXERCISE DATE" means the earlier to occur of (i) December 31,
         2000, (ii) six months following the occurrence of an Initial Public
         Offering, or (iii) entering into an agreement by the Company providing
         for a Sale Transaction.


                                       2
<PAGE>
         "NON-VOTING COMMON STOCK" means the Company's Non-Voting Common Stock,
         par value $.01 per share; PROVIDED, THAT, from and after the time that
         all of the outstanding shares of the Company's Non-Voting Common Stock
         have been converted into shares of the Company's Voting Common Stock
         pursuant to the terms of the Amended and Restated Certificate of
         Incorporation of the Company (the "CERTIFICATE OF INCORPORATION"), all
         references in this Warrant to "Non-Voting Common Stock" shall refer to
         Voting Common Stock.

         "PERSON" means an individual or a corporation, partnership, trust,
         incorporated or unincorporated association, limited liability company,
         joint venture, joint stock company, government (or an agency or
         political subdivision thereof) or other entity of any kind.

         "INITIAL PUBLIC OFFERING" means the initial firm commitment
         underwritten public offering of shares of Common Stock.

         "SALE TRANSACTION" means any consolidation or merger of the Company
         with or into any Person or any Person with or into the Company as a
         result of which the Common Stock is converted into or exchanged for
         Capital Stock or other securities of another Person that are publicly
         traded on a national securities exchange or automated quotation system
         or for cash or for a combination of the foregoing.

         "SHARES" has the meaning set forth in the first paragraph of this
         Warrant.

         "SPECIAL COMMITTEE" means the Special Committee of the Board referred
         to in the Stockholders Agreement for as long as such committee is
         required pursuant to the Stockholders Agreement, and thereafter means
         to the entire Board.

         "STOCKHOLDERS AGREEMENT" means the Stockholders Agreement dated as of
         January 6, 2000 by and among the Company and the stockholders party
         thereto, as amended from time to time.

         "VOTING COMMON STOCK" means the Company's Common Stock, par value $.01
         per share, other than that which is designated Non-Voting Common Stock.

         "WARRANT REGISTER" has the meaning set forth in Section 4.

         2.       EXERCISE OF WARRANT; COMPANY OFFICE; EXPIRATION.

         (a)      GENERAL. This Warrant may be exercised at any time or from
time to time on or after the Initial Exercise Date and shall remain
exercisable thereafter until 5:00 p.m. Central Time on the date five years
after the Initial Exercise Date (the "EXPIRATION TIME"), as to the entire
number or any lesser number of whole Shares covered by this Warrant. This
Warrant shall expire and be deemed canceled immediately after the Expiration
Time if not exercised in accordance with the terms hereof.


                                       3
<PAGE>

         (b)      METHOD FOR EXERCISING. The Holder may exercise this Warrant
by the surrender of this Warrant to the Company at its office at 10 Glenville
Street, Greenwich, Connecticut 06831 or such place as is designated in
writing by the Company, together with a duly executed election in
substantially the form of EXHIBIT A attached hereto and made a part hereof
for all purposes (the "EXERCISE NOTICE"). The Holder must elect in the
Exercise Notice to either (i) to the extent permissible under applicable
securities laws without the registration of the issuance of the Shares
issuable upon such exercise under the Securities Act of 1933, as amended,
exercise some or all of this Warrant for cash or (ii) exercise some or all of
this Warrant on a cashless basis under which the Holder will receive a number
of Shares having a Fair Market Value (determined on the day of exercise)
equal to the excess of (1) the total Fair Market Value (determined on the day
of exercise) of the Shares for which this Warrant is to be exercised on a
cashless basis as specified in the Exercise Notice, over (2) the aggregate
cash Exercise Price for such Shares. If the Holder elects to exercise this
Warrant for cash, the applicable Exercise Price shall be paid by the Holder
by delivering to the Company cash, wire transfer or a certified check, bank
draft or money order payable to the order of the Company in the amount of the
aggregate Exercise Price of the Shares represented by this Warrant to be
issued pursuant to a duly executed Exercise Notice.

         3.       STOCK OWNERSHIP; STOCK CERTIFICATES; PARTIAL EXERCISE. Upon
each exercise of this Warrant, the Holder shall be deemed to be the holder of
record of the Shares issuable upon such exercise as of the close of business
on the day this Warrant is exercised, notwithstanding that the stock transfer
books of the Company shall then be closed or certificates representing such
Shares shall not then have been actually delivered to the Holder. As soon as
possible after each such exercise of this Warrant, the Company shall issue
and deliver to the Holder a certificate or certificates for the Shares
issuable upon such exercise issued in such denominations as may be specified
by Holder in the Exercise Notice and registered in the name of the Holder or,
subject to SECTION 11, such other name or names as shall be designated in the
Holder's election to exercise. If this Warrant should be exercised in part
only, the Company shall, upon surrender of this Warrant for cancellation,
execute and deliver a new Warrant evidencing the right of the Holder to
purchase the balance of the Shares subject to purchase hereunder on the terms
and conditions set forth herein (including all changes and adjustments that
have occurred hereunder).

         4.       COMPANY RECORDS; TRANSFER OR ASSIGNMENT OF WARRANT;
EXCHANGE OF WARRANT. Any Warrants issued in connection herewith or in
substitution herefor, upon complete or partial transfer, assignment or
exercise shall be numbered and shall be registered in the warrant register of
the Company (the "WARRANT REGISTER") as they are issued. The Company shall
treat the registered holder of any Warrant on the Warrant Register as the
owner in fact thereof for all purposes, except that if the Warrant is
properly transferred or assigned in accordance with the terms hereof and
written notice of such transfer or assignment is given to the Company, the
Company shall treat the transferee or assignee as the owner thereof for all
purposes. Subject to the terms hereof, this Warrant shall be transferred by
the Company upon delivery thereof duly endorsed by the Holder or by his duly
authorized attorney or representative, or accompanied by proper evidence of
succession, assignment


                                       4
<PAGE>

or authority to transfer. In case of transfer by executors, administrators,
guardians or other legal representatives, duly authenticated evidence of
their authority shall be produced if requested by the Company in its
reasonable discretion. The Company shall immediately register all assignments
and transfers in the Warrant Register and, upon any registration of
assignment or transfer, the Company shall deliver a new Warrant or Warrants
to the person or entity entitled thereto on the terms and conditions set
forth herein (including all changes and adjustments that have occurred
hereunder). This Warrant, if properly transferred or assigned, may be
exercised by a subsequent Holder without having a new Warrant issued. This
Warrant may be exchanged at the option of the Holder thereof for another
Warrant, or other Warrants, of different denominations and representing in
the aggregate the right to purchase the same number of shares of Common Stock
on the terms and conditions set forth herein (including all changes and
adjustments that have occurred hereunder) upon surrender to the Company or
its duly authorized agent. All provisions of this SECTION 4 shall be subject
to SECTION 10.

         5.       RESERVED STOCK. The Company shall reserve and keep
available at all times solely for the purpose of providing for the exercise
of this Warrant the maximum number of shares of Common Stock as to which this
Warrant may then be exercised. All such shares shall be duly authorized and
free of preemptive rights and, when issued upon such exercise, shall be
validly issued, fully paid and non-assessable.

         6.       PAYMENT OF TAXES. All Common Stock issuable upon the
exercise of this Warrant pursuant to the terms hereof shall be validly issued
as fully paid and non-assessable and without any preemptive rights. The
Company shall pay all expenses in connection with, and all taxes and other
governmental charges that may be imposed with respect to, the issue or
delivery hereof, unless such tax or charge is imposed by law upon Holder, in
which case such taxes or charges shall be paid by Holder. The Company shall
not be required, however, to pay any tax or other charge imposed in
connection with any transfer involved in the issue of any certificate for
Common Stock issuable upon exercise of this Warrant in any name other than
the Holder, and in such case the Company shall not be required to issue or
deliver any share certificate until such tax or other charge has been paid or
it is has been established to the satisfaction of the Company that no such
tax or other charge is due.

         7.       CERTAIN ADJUSTMENTS.

         (a)      NUMBER OF SHARES; EXERCISE PRICE. The number of shares of
Common Stock for which this Warrant is exercisable and the Exercise Price
shall be subject to adjustment from time to time as set forth in this SECTION
7. The Company shall give each Holder notice of any event described below
which requires an adjustment pursuant to this SECTION 7 either at the time of
such event or promptly thereafter.

         (b)      STOCK DIVIDENDS, SUBDIVISIONS AND COMBINATIONS. If at any
time the Company shall:


                                       5
<PAGE>

                  (i) take a record of the holders of its Common Stock for the
         purpose of entitling them to receive a dividend payable in, or other
         distribution of, additional shares of Common Stock,

                  (ii) subdivide its outstanding shares of Common Stock into a
         larger number of shares of Common Stock, or

                  (iii) combine its outstanding shares of Common Stock into a
         smaller number of shares of Common Stock,

then (i) the number of shares of Common Stock for which this Warrant is
exercisable immediately after the occurrence of any such event shall be adjusted
to equal the number of shares of Common Stock which a record holder of the same
number of shares of Common Stock for which this Warrant is exercisable
immediately prior to the occurrence of such event would own or be entitled to
receive after the happening of such event, and (ii) the Exercise Price shall be
adjusted to equal (A) the then current Exercise Price multiplied by the number
of shares of Common Stock for which this Warrant is exercisable immediately
prior to the adjustment divided by (B) the number of shares for which this
Warrant is exercisable immediately after such adjustment.

         (c)      CERTAIN OTHER DISTRIBUTIONS. If at any time the Company
shall take a record of the holders of its Common Stock for the purpose of
entitling them to receive any dividend or other distribution of:

                  (i)  cash,

                  (ii) any evidences of its indebtedness, any shares of its
         stock or any other securities or property of any nature whatsoever
         (other than cash or shares of Common Stock), or

                  (iii) any warrants or other rights to subscribe for or
         purchase any evidences of its indebtedness, any shares of its stock or
         any other securities or property of any nature whatsoever,

then the Company shall make provision such that the holder of this Warrant
shall, upon exercise of this Warrant, receive, in addition to the number of
Shares issuable in connection with such exercise, such cash, evidences of
indebtedness, shares of stock, other securities or property or warrants or other
subscription or purchase rights that would have been distributed with respect to
such Shares if such Shares had been outstanding at the time of such dividend or
distribution after appropriate adjustment to take into account all adjustments
made pursuant to SECTION 7 after such record date and prior to such exercise of
this Warrant. A reclassification of the Common Stock (other than a change in par
value, or from par value to no par value or from no par value to par value) into
shares of Common Stock and shares of any other class of stock shall be deemed a
distribution by Company to the holders of its Common Stock of such shares of
such other class of stock within the meaning


                                       6
<PAGE>

of this SECTION 7(c) and, if the outstanding shares of Common Stock shall be
changed into a larger or smaller number of shares of Common Stock as a part
of such reclassification, such change shall be deemed a subdivision or
combination, as the case may be, of the outstanding shares of Common Stock
within the meaning of SECTION 7(b).

         (d)      OTHER PROVISIONS APPLICABLE TO ADJUSTMENTS UNDER THIS
SECTION. The following provisions shall be applicable to the making of
adjustments to the number of shares of Common Stock for which this Warrant is
exercisable and the Exercise Price provided for in this SECTION 7:

                  (i) WHEN ADJUSTMENTS TO BE MADE. The adjustments required
         by this SECTION 7 shall be made whenever and as often as any
         specified event requiring an adjustment shall occur, except that any
         adjustment to the number of shares of Common Stock for which this
         Warrant is exercisable that would otherwise be required may be
         postponed (except in the case of a subdivision or combination of
         shares of Common Stock, as provided for in SECTION 7(b)) up to, but
         not beyond the date of exercise if such adjustment either by itself
         or with other adjustments not previously made adds or subtracts less
         than 1% of the shares of Common Stock for which this Warrant is
         exercisable immediately prior to the making of such adjustment or
         less than one cent ($.01) to the Exercise Price. Any adjustment
         representing a change of less than such minimum amount (except as
         aforesaid) which is postponed shall be carried forward and made as
         soon as such adjustment, together with other adjustments required by
         this SECTION 7 and not previously made, would result in a minimum
         adjustment or on the date of exercise. For the purpose of any
         adjustment, any specified event shall be deemed to have occurred at
         the close of business on the date of its occurrence.

                  (ii) FRACTIONAL INTERESTS. In computing adjustments under
         this SECTION 7, fractional interests in Common Stock shall be taken
         into account to the nearest 1/100th of a share.

                 (iii) WHEN ADJUSTMENT NOT REQUIRED. If the Company shall
         take a record of the holders of its Common Stock for the purpose of
         entitling them to receive a dividend or distribution or subscription
         or purchase rights and shall, thereafter and before the distribution
         to stockholders thereof, legally abandon its plan to pay or deliver
         such dividend, distribution, subscription or purchase rights, then
         thereafter no adjustment shall be required by reason of the taking
         of such record and any such adjustment previously made in respect
         thereof shall be rescinded and annulled.

                 (iv) ESCROW OF PROPERTY. If after any property or securities
         becomes distributable pursuant to this SECTION 7 by reason of the
         taking of any record of the holders of Common Stock, but prior to
         the occurrence of the event for which such record is taken, and
         Holder exercises this Warrant, any additional securities or other
         property issuable upon exercise by reason of such adjustment shall
         be held in escrow for Holder by the Company to be issued to Holder
         upon and to the extent that the event actually takes place, upon
         payment of the then current Exercise Price. Notwithstanding any
         other provision to the contrary herein, if the

                                       7

<PAGE>

         event for which such record was taken fails to occur or is
         rescinded, then such escrowed property or securities shall be
         canceled by the Company and the escrowed property returned.

         (e) NO IMPAIRMENT. The Company shall not, by amendment of the
Certificate of Incorporation or through any consolidation, merger,
reorganization, transfer of assets, dissolution, issue or sale of securities or
any other voluntary action, avoid or seek to avoid the observance or performance
of any of the terms of this Warrant, and will at all times in good faith assist
in carrying out all of such terms and in the taking of all such actions as may
be necessary or appropriate in order to protect the rights of the Holder of this
Warrant against dilution or other impairment. Without limiting the generality of
the foregoing, the Company (i) will not permit the par value of any Shares
receivable upon the exercise of this Warrant to exceed the amount payable
therefor upon such exercise, (ii) will take all such action as may be necessary
or appropriate in order that the Company may validly and legally issue fully
paid and non-assessable shares of stock on the exercise of this Warrant from
time to time outstanding, and (iii) will not take any action which results in
any adjustment to the Exercise Price if the total number of shares of Common
Stock issuable after such action upon the exercise of all of this Warrant would
exceed the total number of shares of Common Stock then authorized by the
Certificate of Incorporation and available for the purpose of issuance upon such
exercise.

         (f) NOTICE. Whenever there shall be an adjustment as provided in this
SECTION 7, the Company shall promptly cause written notice thereof to be sent to
the Holder, which notice shall set forth the Exercise Price after such
adjustment and a brief statement of the facts requiring such adjustment and the
computation thereof. However, the failure by the Company to satisfy its
obligations under this SECTION 7(f) shall not in any manner affect or alter the
rights of the Holder under this Warrant.

         (g) FRACTIONAL SHARES. The Company shall not be required to issue
fractions of shares of Common Stock or other Capital Stock of the Company upon
the exercise of this Warrant. If any fraction of a Share would be issuable upon
the exercise of any Warrant (or specified portions thereof), the Company shall
purchase such fraction for an amount in cash equal to the same fraction of the
Fair Market Value of such Share of Common Stock on the date of exercise of the
Warrant.

         (h) TREASURY STOCK. For the purposes of this SECTION 7, the sale or
other disposition of any Common Stock theretofore held in the Company's treasury
shall be deemed to be an issue thereof.

         (i) VALID ISSUANCE. All Shares which may be issued upon the exercise of
this Warrant will upon issuance by the Company be duly and validly issued, fully
paid and non-assessable and free from all taxes, liens and charges with respect
to the issuance thereof, and the Company shall take no action which will cause a
contrary result.


                                       8
<PAGE>

         8. CERTAIN CORPORATE EVENTS OR ACTIONS.

         (a) CONSOLIDATION, MERGER, ETC. In case of any consolidation with or
merger of the Company with or into another corporation or other entity (except
for a merger or consolidation in which the Company is the continuing corporation
other than as a subsidiary of another corporation or other entity and there is
no change in or distribution with respect to the Common Stock), or in case of
any sale, lease or conveyance to another corporation or other entity of the
assets of the Company as an entirety or substantially as an entirety, then each
Holder shall have the right thereafter to receive upon exercise of this Warrant
the kind and amount of shares of stock and other securities, property, cash or
any combination thereof receivable upon such consolidation, merger, sale, lease
or conveyance by a holder of the number of Shares for which this Warrant might
have been exercised immediately prior to such consolidation, merger, sale, lease
or conveyance, and such successor, purchasing, leasing or receiving corporation
or other entity, as the case may be, shall, prior to and as a condition to the
occurrence of such event, (i) execute with the Holder an agreement providing
that the Holder shall have the right thereafter to receive upon exercise of this
Warrant the kind and amount of shares of stock and other securities, property,
cash or any combination thereof receivable upon such consolidation, merger,
sale, lease or conveyance by a holder of the number of Shares for which this
Warrant might have been exercised immediately prior to such consolidation,
merger, sale, lease or conveyance, and (ii) make effective provision in the
Certificate of Incorporation or similar governing instrument or otherwise, if
needed, in order to effect such agreement. Such agreement shall provide for
adjustments which shall be equivalent to the adjustments in SECTION 7 and shall
contain provisions equivalent to this SECTION 8.

         (b) RECLASSIFICATION, ETC. In case of any reclassification or change of
the Shares issuable upon exercise of this Warrant, the Holder shall have the
right thereafter to receive upon exercise of this Warrant the kind and amount of
shares of stock and other securities, property, cash or any combination thereof
receivable upon such reclassification or change by a holder of the number of
shares of Common Stock into which this Warrant would have been exercisable
immediately prior to such reclassification or change. Thereafter, appropriate
provision (as determined by the Board in good faith) shall be made for
adjustments which shall be equivalent to the adjustments in SECTION 7. This
SECTION 8(b) shall be applicable to successive reclassifications or changes.

         9. CERTAIN NOTICES. In case at any time the Company shall propose:

         (a) to pay any dividend or make any distribution on shares of Common
Stock or to fix a record date for the making of any such dividend or
distribution to holders of Common Stock; or

         (b) to take, or fix a record date for, any action that would result in
any adjustment to the Exercise Price pursuant to SECTION 7;

         (c) to effect any reclassification or change of outstanding shares of
Common Stock, or consolidation or merger, or sale, lease or conveyance of
property, of the type addressed in SECTION 8;


                                       9
<PAGE>

or

         (d) to effect any voluntary or involuntary liquidation, dissolution
or winding-up of the Company;

then, and in any one or more of such cases, the Company shall give written
notice thereof to the Holder at least 10 days prior to the date on which (i) the
books of the Company shall close, or a record date shall be set, for any such
action described in SECTION 9(a) OR (b) or (ii) such reclassification, change,
consolidation, merger, sale, lease, conveyance, liquidation, dissolution or
winding-up shall be effective, as the case may be.

         10. EXPENSES. Subject to SECTION 6, the Company shall pay all costs,
fees, taxes (other than any federal or state income or stock transfer taxes) and
expenses payable in connection with the preparation, issuance and delivery from
time to time of Shares or other securities issued upon the exercise of this
Warrant.

         11. RESTRICTIONS ON TRANSFER. The Holder, by its acceptance hereof,
represents and warrants that it is acquiring this Warrant and any Shares issued
upon the exercise of this Warrant for investment purposes, for its own account,
and not with an intent to sell or distribute this Warrant or any such Shares
except in compliance with applicable United States federal and state securities
law. THE HOLDER AGREES THAT IT MAY NOT TRANSFER, SELL, ASSIGN OR PLEDGE THIS
WARRANT EXCEPT AS PERMITTED BY THE STOCKHOLDERS AGREEMENT. In addition, neither
this Warrant nor any of the Shares issued upon the exercise of this Warrant, nor
any interest in either, may be sold, assigned, pledged, hypothecated, encumbered
or in any other manner transferred or disposed of, in whole or in part, except
in compliance with applicable United States federal and state securities laws
and the terms and conditions hereof. The provisions of this SECTION 11 shall be
binding upon all subsequent holders of this Warrant, if any. The Shares or other
securities issued upon exercise of this Warrant shall be subject to a
stop-transfer order and the certificate or certificates evidencing any such
shares shall bear the following legend:

         THE SECURITIES REPRESENTED BY THIS CERTIFICATE ARE SUBJECT TO CERTAIN
         TRANSFER RESTRICTIONS SET FORTH IN THE STOCKHOLDERS AGREEMENT DATED AS
         OF JANUARY 6, 2000 BY AND AMONG THE COMPANY AND CERTAIN STOCKHOLDERS
         THEREOF, AS AMENDED. THE SECURITIES REPRESENTED BY THIS CERTIFICATE
         HAVE BEEN ACQUIRED FOR INVESTMENT AND HAVE NOT BEEN REGISTERED UNDER
         THE SECURITIES ACT OF 1933, AS AMENDED, OR THE SECURITIES LAWS OF ANY
         STATE OR OTHER JURISDICTION. SUCH SECURITIES MAY NOT BE SOLD, ASSIGNED
         OR OTHERWISE TRANSFERRED EXCEPT UPON SUCH REGISTRATION OR UPON DELIVERY
         TO THE COMPANY OF AN OPINION OF COUNSEL REASONABLY SATISFACTORY TO THE
         CORPORATION STATING THAT SUCH SALE, ASSIGNMENT OR TRANSFER IS EXEMPT
         FROM REGISTRATION UNDER SUCH ACT AND LAWS.

         12. REGISTRATION OF COMMON STOCK; LISTING. At any such time as the
Common Stock is listed for trading on a national securities exchange or the
Nasdaq Stock Market, the Company will,


                                       10
<PAGE>

at its expense, obtain promptly and maintain the approval of all securities
exchanges (including, for this purpose, The Nasdaq Stock Market) on which the
Common Stock is then listed for trading for an additional listing, upon
official notice of issuance, of the Shares issuable upon exercise of this
Warrant and maintain the listing of such Shares after their issuance.

         13. LOSS, THEFT, ETC. Upon receipt of evidence satisfactory to the
Company of the loss, theft, destruction or mutilation of any Warrant and upon
surrender and cancellation of any Warrant if mutilated, the Company shall
execute and deliver to the Holder thereof a new Warrant in the form and
substance of the lost, stolen, destroyed or mutilated Warrant (including all
changes and adjustments that have occurred hereunder). In any such event, the
Company shall have the right to require the Holder to post a bond as security
therefor, the cost of which shall be paid by the Holder.

         14. NO RIGHTS OR LIABILITIES AS A STOCKHOLDER. Nothing contained in
this Warrant shall be construed as conferring upon the Holder hereof any rights
as a stockholder of the Company or as imposing any obligation upon such Holder
to purchase any securities or as imposing any liability upon such Holder as a
stockholder of the Company, whether such obligation or liability is asserted by
the Company or by creditors of the Company at law or in equity.

         15. GOVERNING LAW. This Warrant shall be governed by and construed in
accordance with the internal laws of the State of Delaware, without giving
effect to conflicts of laws principles thereof.

         16. REMEDIES. The Company stipulates that the remedies at law of the
Holder of this Warrant in the event of any default or threatened default by the
Company in the performance of or compliance with any of the terms of this
Warrant are not and will not be adequate, and that, to the extent permitted by
applicable law, such terms may be specifically enforced by a decree for the
specific performance of any agreement contained herein or by an injunction
against a violation of any of the terms hereof or otherwise.

         17. NOTICES. All notices and other communications provided for herein
shall be in writing and shall be effective (i) on the day on which delivered if
delivered personally or transmitted by telex or telegram or telecopier with
evidence of receipt, (ii) one Business Day after the date on which such notices
are delivered to a nationally recognized courier service with evidence of
receipt, or (iii) three Business Days after the date on which the same is
deposited, postage prepaid, in the U.S. Mail, sent by certified mail, return
receipt requested, postage prepaid, in each case and addressed (a) if to any
Holder of any Warrant, to the address of such Holder as set forth in the Warrant
Register or to such other address as such Holder has notified the Company of in
writing or (b) if to the Company, to the address set forth in SECTION 2 or to
such other address as the Company may designate by written notice; PROVIDED,
HOWEVER, that the exercise of any Warrant shall be effected only in the manner
provided in SECTION 2.

         18. MISCELLANEOUS. This Warrant and any terms hereof may be changed,
waived,


                                       11
<PAGE>

discharged or terminated only by an instrument in writing signed by the party
against which enforcement of such change, waiver, discharge or termination is
sought. Any provision of this Warrant which shall be prohibited or
unenforceable in any jurisdiction shall, as to such jurisdiction, be
ineffective to the extent of such prohibition or unenforceability without
invalidating the remaining provisions hereof, and any such prohibition or
unenforceability in any jurisdiction shall not invalidate or render
unenforceable such provision in any other jurisdiction. To the extent
permitted by applicable law, the Company waives any provision of law which
shall render any provision hereof prohibited or unenforceable in any respect.

         19. NONWAIVER AND EXPENSES. No course of dealing or any delay or
failure to exercise any right hereunder on the part of Holder shall operate as a
waiver of such right or otherwise prejudice Holder's rights, powers or remedies.
If the Company fails to comply with any other provision of this Warrant, the
Company shall pay to Holder such amounts as shall be sufficient to cover any
costs and expenses including, but not limited to, reasonable attorneys' fees,
including those of appellate proceedings, incurred by Holder in collecting any
amounts due pursuant hereto or in otherwise enforcing any of its rights, powers
or remedies hereunder.

         20. SUCCESSORS AND ASSIGNS. Subject to the provisions of SECTION 11
hereof, this Warrant and the rights evidenced hereby shall inure to the benefit
of and be binding upon the successors of the Company and the successors and
assigns of Holder. The provisions of this Warrant are intended to be for the
benefit of all Holders from time to time of this Warrant and shall be
enforceable by any such Holder.

         21. AMENDMENT. This Warrant may be modified or amended or the
provisions hereof waived by the written consent of the Company and the Holders.

         22. HEADINGS. The headings used in this Warrant are for the convenience
of reference only and shall not, for any purpose, be deemed a part of this
Warrant.


                                       12
<PAGE>

         IN WITNESS WHEREOF, the Company has caused this Warrant to be duly
executed and its corporate seal to be impressed hereon and attested by its
Secretary or an Assistant Secretary.

Dated: July __, 2000                                 TNPC, INC.


                                                     By:
                                                        ---------------------
                                                     Name:
                                                          -------------------
                                                     Title:
                                                           ------------------


ATTEST


By:
   ------------------------
Name:
     ----------------------
Title:
      ---------------------


                                       13
<PAGE>

                                                            EXHIBIT A TO WARRANT

To:      TNPC, Inc.
         10 Glenville Street
         Greenwich, Connecticut 06831

                              ELECTION TO EXERCISE

         The undersigned hereby exercises his or its rights to subscribe for
__________ Shares covered by the within Warrant. The undersigned elects pursuant
to SECTION 2 of the Warrant:

         (i)      ____ to tender payment herewith in the amount of
                  $____________; or

         (ii)     ____ to exercise the Warrant on a cashless basis as provided
                  in SECTION 2(b);

in accordance with the terms thereof, and requests that certificates for such
shares in the following denominations be issued in the name of, and delivered
to, the person at the following address:


                  Denominations:
                                 ---------------------------------------------

                  ------------------------------------------------------------

                  ------------------------------------------------------------

                  ------------------------------------------------------------
                          (Print Address and Social Security Number or
                          Employer Identification Number as applicable)

and, if said number of Shares shall not be all the Shares covered by the within
Warrant, that a new Warrant for the balance remaining of the Shares covered by
the within Warrant be registered in the name of, and delivered to, the
undersigned at the address stated below:

Date:  __________, ____                     Name:
                                                 --------------------------
                                                         (Print)

                                                 --------------------------
                                                        (Signature)

                                         Address:
                                                 --------------------------
                                                 --------------------------


                                       14