Exhibit 99(d)(i)


                           TENDER AND VOTING AGREEMENT

         TENDER AND VOTING AGREEMENT, dated as of January 19, 2000 (this
"AGREEMENT"), between Elyo S.A., a societe anonyme organized under the laws of
France ("PARENT"), T Acquisition Corp., a Delaware corporation and a wholly
owned subsidiary of Parent ("PURCHASER") and each of the persons listed on
Schedule A hereto (each a "STOCKHOLDER" and, collectively, the "STOCKHOLDERS").

                                    RECITALS

         WHEREAS, Parent, Purchaser and Trigen Energy Corporation, a Delaware
corporation (the "Company") propose to enter into an Agreement and Plan of
Merger dated as of the date hereof (as the same may be amended or supplemented,
the "MERGER AGREEMENT") providing for, among other things, the making of the
Offer by Purchaser for all of the issued and outstanding shares of common stock,
par value $0.01 per share, of the Company (referred to herein as either the
"SHARES" or "COMMON STOCK") and the merger of Purchaser with and into the
Company on the terms and conditions set forth in the Merger Agreement (the
"Merger");

         WHEREAS, each Stockholder is the beneficial owner of the Shares and
Options set forth opposite such Stockholder's name on Schedule A hereto
(collectively referred to herein as the "Shares" of such Stockholder); such
Shares, as such Shares may be adjusted by stock dividend, stock split,
recapitalization, combination or exchange of shares, merger, consolidation,
reorganization or other change or transaction of or by the Company, together
with Shares issuable upon the exercise of Options; and

         WHEREAS, as a condition to their willingness to enter into the Merger
Agreement, Parent and Purchaser have requested that the Stockholders enter into
this Agreement;

         NOW, THEREFORE, to induce Parent and Purchaser to enter into, and in
consideration of their entering into, the Merger Agreement, and in consideration
of the premises and the representations, warranties and agreements contained
herein, the parties agree as follows:

         Section 1. CERTAIN DEFINITIONS. Capitalized terms used but not
otherwise defined herein have the meanings ascribed to such terms in the Merger
Agreement.

         Section 2. REPRESENTATIONS AND WARRANTIES OF THE STOCKHOLDERS. Each
Stockholder, severally and not jointly, represents and warrants to Parent and
Purchaser, as of the date hereof, as follows:





              (a) The Shares (including the Options) constitute all of the
securities (as defined in Section 3(a)(10) of the Exchange Act), of the Company
beneficially owned, directly or indirectly, by the Stockholder.

              (b) Except for the Shares (including the Options), such
Stockholder does not, directly or indirectly, beneficially own or have any
option, warrant or other right to acquire any securities of the Company that are
or may by their terms become entitled to vote or any securities that are
convertible or exchangeable into or exercisable for any securities of the
Company that are or may by their terms become entitled to vote, nor is such
Stockholder subject to any contract, commitment, arrangement, understanding,
restriction or relationship (whether or not legally enforceable), other than
this Agreement, that provides for such Stockholder to vote or acquire any
securities of the Company. Such Stockholder holds exclusive power to vote the
Shares and has not granted a proxy to any other Person to vote the Shares
(including those issuable upon exercise of the Options), subject to the
limitations set forth in this Agreement.

              (c) This Agreement has been duly executed and delivered by such
Stockholder and, assuming due authorization, execution and delivery of this
Agreement by Parent and Purchaser, is a valid and binding obligation of the
Stockholder enforceable against such Stockholder in accordance with its terms,
except as such enforceability may be limited by (i) applicable bankruptcy,
insolvency, reorganization, moratorium or other similar laws affecting the
enforcement of creditors' rights generally; and (ii) general principles of
equity (regardless of whether such enforceability is considered in a proceeding
in equity or at law).

              (d) No investment banker, broker, finder or other intermediary is,
or will be, entitled to a fee or commission from Purchaser, Parent or the
Company in respect of this Agreement based on any arrangement or agreement made
by or on behalf of such Stockholder in his or her capacity as a stockholder of
the Company.

              (e) Such Stockholder understands and acknowledges that Parent is
entering into, and causing Purchaser to enter into, the Merger Agreement in
reliance upon such Stockholder's execution and delivery of this Agreement.

         Section 3. REPRESENTATIONS AND WARRANTIES OF PARENT AND PURCHASER.
Parent and Purchaser represent and warrant to the Stockholders as of the date
hereof:

              (a) Each of Parent and Purchaser is a company duly organized,
validly existing and in good standing under the laws of their respective
jurisdictions of incorporation, has the requisite company power and authority to
execute and deliver this Agreement and to consummate the transactions


                                       2




contemplated hereby, and has taken all necessary company action to authorize the
execution, delivery and performance of this Agreement.

              (b) This Agreement has been duly executed and delivered by Parent
and Purchaser and, assuming the due authorization, execution and delivery of
this Agreement by the Company and the Stockholders, is a valid and binding
obligation of each of Parent and Purchaser, enforceable against each of them in
accordance with its terms, except as such enforceability may be limited by (i)
applicable bankruptcy, insolvency, reorganization, moratorium or other similar
laws affecting the enforcement of creditors' rights generally; and (ii) general
principles of equity (regardless of whether such enforceability is considered in
a proceeding in equity or at law).

         Section 4. TRANSFER OF THE SHARES. During the term of this Agreement,
except as otherwise expressly provided herein, each Stockholder agrees that such
Stockholder will not (a) tender into any tender or exchange offer or otherwise
sell, transfer, pledge, assign, hypothecate or otherwise dispose of, or encumber
with any Lien, any of the Shares, (b) acquire any shares of Common Stock or
other securities of the Company (otherwise than in connection with a transaction
of the type described in Section 5 or by exercising any of the Options), (c)
deposit the Shares into a voting trust, enter into a voting agreement or
arrangement with respect to the Shares or grant any proxy or power of attorney
with respect to the Shares, (d) enter into any contract, option or other
arrangement (including any profit sharing arrangement) or undertaking with
respect to the direct or indirect acquisition or sale, transfer, pledge,
assignment, hypothecation or other disposition of any interest in or the voting
of any Shares or any other securities of the Company, (e) exercise any rights
(including, without limitation, under Section 262 of the Delaware General
Corporation Law) to demand appraisal of any Shares which may arise with respect
to the Merger, or (f) take any other action that would in any way restrict,
limit or interfere with the performance of such Stockholder's obligations
hereunder or the transactions contemplated hereby or which would otherwise
diminish the benefits of this Agreement to Parent or Purchaser.

         Section 5. ADJUSTMENTS. (a) In the event (i) of any stock dividend,
stock split, recapitalization, reclassification, combination or exchange of
shares of capital stock or other securities of the Company on, of or
affecting the Shares or the like or any other action that would have the
effect of changing a Stockholder's ownership of the Company's capital stock
or other securities or (ii) a Stockholder becomes the beneficial owner of any
additional Shares of or other securities of the Company, then the terms of
this Agreement will apply to the shares of capital stock held by such
Stockholder immediately following the effectiveness of the events described
in clause (i) or such Stockholder becoming the beneficial owner

                                       3




thereof, as described in clause (ii), as though they were Shares hereunder.

              (b) Each Stockholder hereby agrees, while this Agreement is in
effect, to promptly notify Parent and Purchaser of the number of any new Shares
acquired by such Stockholder, if any, after the date hereof.

         Section 6. TENDER OF SHARES. Each Stockholder hereby agrees that such
Stockholder will validly tender (or cause the record owner of such shares to
validly tender) and sell (and not withdraw) pursuant to and in accordance with
the terms of the Offer not later than the fifth business day after commencement
of the Offer (or if the Stockholder acquires Shares after the date hereof, the
earlier of the expiration date of the Offer and the fifth business day after
such Shares are acquired by such Stockholder), or, if the Stockholder has not
received the Offer Documents by such time, within two business days following
receipt of such documents, all of the then outstanding shares of Common Stock
beneficially owned by such Stockholder (including the shares of Common Stock
outstanding as of the date hereof and shares issued upon exercise (if any) of
the Options, in each case as set forth on Schedule A hereto opposite such
Stockholder's name). Upon the purchase by Parent of all of such then outstanding
shares of Common Stock beneficially owned by such Stockholder pursuant to the
Offer in accordance with this Section 6, this Agreement will terminate as it
relates to such Stockholder. In the event, notwithstanding the provisions of the
first sentence of this Section 6, any Shares beneficially owned by a Stockholder
are for any reason withdrawn from the Offer or are not purchased pursuant to the
Offer, such Shares will remain subject to the terms of this Agreement. Each
Stockholder acknowledges that Parent's obligation to accept for payment and pay
for the shares of Common Stock tendered in the Offer is subject to all the terms
and conditions of the Offer.

         Section 7. VOTING AGREEMENT. Each Stockholder, by this Agreement, does
hereby (a) agree to appear (or not appear, if requested by Parent or Purchaser)
at any annual, special, postponed or adjourned meeting of the stockholders of
the Company or otherwise cause the Shares such Stockholder beneficially owns to
be counted as present (or absent, if requested by Parent or Purchaser) thereat
for purposes of establishing a quorum and to vote or consent, and (b) constitute
and appoint Parent and Purchaser, or any nominee thereof, with full power of
substitution, during and for the term of this Agreement, as his true and lawful
attorney and proxy for and in his name, place and stead, to vote all the Shares
such Stockholder beneficially owns at the time of such vote, at any annual,
special, postponed or adjourned meeting of the stockholders of the Company (and
this appointment will include the right to sign his or its name (as stockholder)
to any consent, certificate or other document relating to the Company that laws
of the State of Delaware may require or permit), in the case of both (a) and (b)
above, (x)


                                       4




in favor of approval and adoption of the Merger Agreement and approval and
adoption of the Merger and the other transactions contemplated thereby. This
proxy and power of attorney is a proxy and power coupled with an interest, and
each Stockholder declares that it is irrevocable until this Agreement shall
terminate in accordance with its terms. Each Stockholder hereby revokes all and
any other proxies with respect to the Shares that such Stockholder may have
heretofore made or granted. For Shares as to which a Stockholder is the
beneficial but not the record owner, such Stockholder shall use his or its best
efforts to cause any record owner of such Shares to grant to Parent a proxy to
the same effect as that contained herein. Each Stockholder hereby agrees to
permit Parent and Purchaser to publish and disclose in the Offer Documents and
the Proxy Statement and related filings under the securities laws such
Stockholder's identity and ownership of Shares and the nature of his or its
commitments, arrangements and understandings under this Agreement.

         Section 8. TERMINATION. This Agreement will terminate (a) as to any
Stockholder upon the purchase of all the Shares beneficially owned by such
Stockholder pursuant to the Offer in accordance with Section 6, or (b) on the
earlier to occur of (i) the Effective Time or (ii) the date the Merger Agreement
is terminated in accordance with its terms.

         Section 9. FEES AND EXPENSES. Except as otherwise expressly provided
herein or in the Merger Agreement, whether of not the Merger is consummated, all
costs and expenses incurred in connection with this Agreement and the
transactions contemplated hereby shall be paid by the party incurring such costs
and expenses.

         Section 10. FURTHER ASSURANCES. Each party hereto will execute and
deliver all such further documents and instruments and take all such further
action as may be reasonably necessary in order to consummate the transactions
contemplated hereby.

         Section 11. PUBLICITY. A Stockholder shall not issue any press release
or otherwise make any public statements with respect to this Agreement or the
Merger Agreement or the other transactions contemplated hereby or thereby
without the consent of Parent and Purchaser, except as may be required by Law or
applicable stock exchange rules.

         Section 12. STOCKHOLDER CAPACITY. No person executing this Agreement
makes any agreement or understanding herein in such Stockholder's capacity as a
director or officer of the Company or any subsidiary of the Company. Each
Stockholder signs solely in such Stockholder's capacity as the beneficial owner
of such Stockholder's Shares and nothing herein shall limit or affect any
actions taken


                                       5




by a Stockholder in such Stockholder's capacity as an officer or director of the
Company or any subsidiary of the Company to the extent specifically permitted by
the Merger Agreement.

         Section 13. ENFORCEMENT. The parties hereto agree that irreparable
damage may occur in the event that any of the provisions of this Agreement were
not performed in accordance with its specific terms or was otherwise breached.
It is accordingly agreed that the parties shall be entitled to an injunction or
injunctions to prevent breaches of this Agreement and to enforce specifically
the terms and provisions hereof in any New York Court, this being in addition to
any other remedy to which they are entitled at law or in equity for damages or
otherwise.

         Section 14. MISCELLANEOUS.

              (a) All representations and warranties contained herein will
survive for twelve months after the termination hereof. The covenants and
agreements made herein will survive in accordance with their respective terms.

              (b) Any provision of this Agreement may be waived at any time by
the party that is entitled to the benefits thereof. No such waiver, amendment or
supplement will be effective unless in writing and signed by the party or
parties sought to be bound thereby. Any waiver by any party of a breach of any
provision of this Agreement will not operate as or be construed to be a waiver
of any other breach of such provision or of any breach of any other provision of
this Agreement. The failure of a party to insist upon strict adherence to any
term of this Agreement or one or more sections hereof will not be considered a
waiver or deprive that party of the right thereafter to insist upon strict
adherence to that term or any other term of this Agreement.

              (c) This Agreement constitutes the entire agreement among the
parties hereto with respect to the subject matter hereof, and supersedes all
prior agreements among the parties with respect to such matters. This Agreement
may not be amended, changed, supplemented, waived or otherwise modified, except
upon the delivery of a written agreement executed by the parties hereto.

              (d) This Agreement shall be governed by and construed in
accordance with the laws of the State of Delaware without regard to its rules of
conflict of laws. Each of the Stockholders, Parent and Purchaser hereby
irrevocably and unconditionally consents to submit to the exclusive jurisdiction
of the United States District Court for the State of Delaware or any court of
the State of Delaware (the "DELAWARE COURTS") for any litigation arising out of
or relating to this Agreement and the transactions contemplated hereby (and
agrees not to commence any litigation relating thereto except in such courts),
waives any


                                       6




objection to the laying of venue of any such litigation in the Delaware Courts
and agrees not to plead or claim in any Delaware Court that such litigation
brought therein has been brought in an inconvenient forum. Parent hereby
appoints The Corporation Trust Company as agent for service of process. The
address of such agent for service of process is Corporation Trust Center, 1209
Orange Street, Wilmington, Delaware 19801.

              (e) The descriptive headings contained herein are for convenience
and reference only and will not affect in any way the meaning or interpretation
of this Agreement. In this Agreement, unless the context otherwise requires,
words describing the singular number shall include the plural and vice versa,
and words denoting any gender shall include all genders and words denoting
natural persons shall include corporations and partnerships and vice versa.
Whenever the words "include," "includes" or "including" are used in this
Agreement, they shall be understood to be followed by the words "without
limitation."

              (f) All notices and other communications hereunder will be in
writing and will be given (and will be deemed to have been duly given upon
receipt) by delivery in person, by telecopy, or by registered or certified mail,
postage prepaid, return receipt requested, addressed as follows:

         If to Parent or Purchaser to:

         Elyo S.A.
         235 Avenue Georges Clemenceau BP 4601
         92746 Nanterre Cedex
         France
         Attention:  Michel Caillard
         Fax:  (01 41 20 10 10)

         with copies to:

         Fried, Frank, Harris, Shriver & Jacobson
         One New York Plaza
         New York, New York 10004
         Attention:  Jeffrey Bagner, Esq.
         Telecopy:  (212) 859-4000

         If to a Stockholder, at the address set forth on Schedule A hereto or
to such other address as any party may have furnished to the other parties in
writing in accordance herewith.

              (g) This Agreement may be executed by the parties hereto in
separate


                                       7




counterparts, each of which, when so executed and delivered, shall be an
original. All such counterparts shall together constitute one and the same
instrument. Each counterpart may consist of a number of copies hereof, each
signed by less than all, but together signed by all, of the parties hereto.

              (h) This Agreement is binding upon and is solely for the benefit
of the parties hereto and their respective successors, legal representatives and
assigns. Neither this Agreement nor any of the rights, interests or obligations
under this Agreement will be assigned by any of the parties hereto without the
prior written consent of the other parties, except that Parent and Purchaser
will have the right to assign to any direct or indirect wholly owned subsidiary
of Parent or Purchaser any and all rights and obligations of Parent or Parent
under this Agreement, provided that any such assignment will not relieve either
Parent or Purchaser from any of its obligations hereunder.

              (i) Any term or provision of this Agreement that is invalid or
unenforceable in any jurisdiction shall, as to that jurisdiction, be ineffective
to the extent of such invalidity or unenforceability without rendering invalid
or unenforceable the remaining terms and provisions of this Agreement or
affecting the validity or enforceability of any of the terms or provisions of
this Agreement in any other jurisdiction. If any provision of this Agreement is
so broad as to be unenforceable, the provision shall be interpreted to be only
so broad as is enforceable.

              (j) All rights, powers and remedies provided under this Agreement
or otherwise available in respect hereof at law or in equity will be cumulative
and not alternative, and the exercise of any thereof by either party will not
preclude the simultaneous or later exercise of any other such right, power or
remedy by such party.


                                       8




              IN WITNESS WHEREOF, each of the Parent and Purchaser has caused
this Agreement to be signed by its officer or director thereunto duly authorized
and each Stockholder has signed this Agreement, all as of the date first written
above.

                                  ELYO S.A.

                                  By: /s/ Olivier Degos
                                      -------------------------------
                                      Name:  Olivier Degos
                                      Title: Corporate Vice President

                                  T ACQUISITION CORP.

                                  By: /s/ Olivier Degos
                                      -------------------------------
                                      Name:  Olivier Degos
                                      Title: Secretary

                                  STOCKHOLDERS:

                                  /s/ George F. Keane
                                  -----------------------------------
                                  GEORGE F. KEANE

                                  /s/ Charles E. Bayless
                                  -----------------------------------
                                  CHARLES E. BAYLESS

                                  /s/ Charles E. Bayless, Trustee
                                  -----------------------------------
                                  BAYLESS FAMILY TRUST


                                       9







                                   SCHEDULE A

                                                                     Number             Number
Stockholder                         Address                        of Shares          of Options
- -----------                         -------                        ---------          ----------
                                                                              
George F. Keane                  237 Mayfield                       27,200             30,000
                                 Trumbull, CT  06611

Charles E. Bayless               7300 North Sunset                  2,348.346*         10,000
                                  Canyon Drive
                                 Tucson, AR  85718

Bayless Family Trust             7300 North Sunset                  9,149
                                  Canyon Drive
                                 Tucson, AR  85718

With copies to:

W. Brinkley Dickerson, Jr.       Troutman Sanders LLP
                                 600 Peachtree Street N.E.
                                 Suite 5200
                                 Atlanta, GE  30308




- ----------
*   Through October 13, 1999, plus additional deferred shares and reinvestments
granted to date.