Exhibit 10.17


                              [Thermo Fibertek Inc. Letterhead]


                                                           February 12, 2001

Thermo Fibergen Inc.
8 Alfred Circle
Bedford, Massachusetts  01730
Attn: Dr. Yiannis A. Monovoukas,
President and Chief Executive Officer

Re: Agreement to make a loan of up to $5,000,000

Ladies and Gentlemen:

        Reference is hereby made to those certain Redemption Rights issued by
Thermo Fibergen Inc., a Delaware corporation ("Thermo Fibergen"), in its public
offering of Units consisting of one share of Thermo Fibergen's Common Stock and
one Redemption Right pursuant to and as more fully described in that certain
Registration Statement filed with the Securities and Exchange Commission on July
3, 1996, as amended (the "Registration Statement"). Thermo Fibergen is a
publicly-traded subsidiary of Thermo Fibertek Inc., a Delaware corporation
("Thermo Fibertek"), which is a publicly-traded subsidiary of Thermo Electron
Corporation, a Delaware corporation. Capitalized terms used herein without
definition shall have the meaning ascribed to such terms in the Registration
Statement.

        WHEREAS, Each Redemption Right entitles the holder to sell one share of
Thermo Fibergen's Common Stock to Thermo Fibergen during September 2000 (the
"Initial Redemption") and September 2001 (the "Final Redemption"), for an amount
of cash equal to the initial public offering price per unit;

        WHEREAS, Thermo Fibergen used available working capital to fund the
Initial Redemption and intends to use available working capital to fund the
Final Redemption in September 2001; and

        WHEREAS, In the event that Thermo Fibergen's working capital is
insufficient to fund the Final Redemption and to meet its other working capital
needs, Thermo Fibergen desires to have Thermo Fibertek agree to make, and Thermo
Fibertek is willing to agree to make, a loan to Thermo Fibergen to satisfy the
Final Redemption obligation and other working capital needs.

        NOW, THEREFORE, the parties hereto (the "Parties") hereby agree that in
the event that Thermo Fibergen's working capital is insufficient to fund the
Final Redemption and to meet its other working capital needs, upon reasonable
request by Thermo Fibergen on or before December 31, 2001 and subject to and
upon commercially reasonable terms and conditions mutually satisfactory to the
Parties, Thermo Fibertek shall make a loan to Thermo Fibergen of up to FIVE
MILLION DOLLARS ($5,000,000) in original principal amount (the "Loan") bearing
interest at a commercially reasonable rate for the Final Redemption obligations
and other working capital needs of Thermo Fibergen. Thermo Fibergen's obligation
to repay the principal of and interest on such Loan shall be evidenced by a
promissory note in form and substance mutually satisfactory to the Parties;
provided, however, that Thermo Fibergen's obligation to make any specific
payment of principal of and/or interest on the Loan shall be conditioned on the
ability of Thermo Fibergen to meet reasonable cash flow requirements at the time
of such specified payment, which cash flow requirements shall be mutually
satisfactory to the Parties.

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        Please indicate your acceptance of the foregoing by signing and
returning to the undersigned an original counterpart of this letter.


                                Very truly yours,

                                THERMO FIBERTEK INC.


                                By:      __________________________________
                                Name:    Jonathan W. Painter
                                Title:   Executive Vice President, Operations





Accepted, acknowledged and agreed by the undersigned as of the date first above
written:

THERMO FIBERGEN INC.


By:    __________________________________
Name:  Yiannis A. Monovoukas
Title: President