February 11, 2000

Mr. Parimal S. Patel
10 Gould Road
Bedford, MA 01730

Dear Parimal:

As you know,  Thermo Electron  Corporation  recently  announced a corporate wide
reorganization.  As part of that  reorganization,  Thermo  Electron  Corporation
announced  that Thermo  Ecotek  Corporation  will not be considered to be a core
business.  Therefore,  the next  twelve to  eighteen  months will be a period of
challenge and transition for Thermo Ecotek ("TCK").  We recognize and appreciate
your past  contributions  to TCK and would like you to continue your  employment
with us.

Transition Bonus Program

In order to provide an incentive for you to remain with TCK during this critical
period of time we are granting you a Transition Bonus in the amount of $179,500.
Thirty percent (30%) of the  Transition  Bonus will be paid on February 15, 2001
and seventy  percent (70%) of the Transition  Bonus will be paid you on February
15, 2002.  Payment of the Transition Bonus is also subject to the other terms of
this Agreement.

Terms of this Agreement

If you voluntarily  terminate your employment with TCK or you are terminated for
"Cause" (as defined  below)  before  February 15, 2001 or February 15, 2002,  as
applicable, you will not receive the Transition Bonus. However, you may keep any
portion  of the  Transition  Bonus  that  has  previously  been  paid.  If  your
employment is terminated  prior to February 15, 2002 without "Cause" or if there
is a "Change in Control"  of TCK (as  defined  below) you will be paid your full
Transition  Bonus.  If you  voluntarily  obtain  employment with Thermo Electron
Corporation or one of its  subsidiaries,  you will be paid your Transition Bonus
prorated on a daily basis to the date of your employment with Thermo Electron or
its subsidiaries.

TCK will continue to employ you as an employee-at-will and you will receive your
regular  compensation and benefits.  However, TCK retains the right to terminate
your  employment at any time with or without Cause,  but if  termination  occurs
without  Cause or due to a Change in Control,  you will  receive  payment of the
Transition  Bonus,  as  outlined  above.  You  retain  the right to  voluntarily
terminate your services with TCK at any time.


<PAGE>



For  purposes  of this  Agreement,  "Cause"  shall be  determined  by TCK in the
exercise of good faith and reasonable judgement. "Cause" will include but not be
limited to,  breach of this  Agreement by you, any act by you of gross  personal
misconduct,  gross insubordination,  material  misappropriation of funds, fraud,
dishonesty,  gross  neglect  of or failure  to  perform  the  duties  reasonably
required of you pursuant to your  employment,  engaging in  activities  that are
competitive with Thermo Ecotek Corporation's business or any conduct which is in
willful  violation  of any  applicable  law or  regulation  pertaining  to TCK's
business.

"Change  of  Control"  shall  mean the  merger,  consolidation,  reorganization,
liquidation, dissolution or similar transaction entered into by TCK (except into
Thermo  Electron  Corporation),  the sale or  disposition  of 50% or more of the
existing assets of TCK in one or a series of  transactions,  change in ownership
of 50% or more of the beneficial  ownership of the outstanding  shares of common
stock of TCK.

Severance Payments

Attached is a separate letter,  which outlines the Enhanced  Severance  Program,
which you are eligible for, in the event that you are  terminated  without Cause
or if there is Change in Control of TCK on or prior to February  15,  2002.  The
Enhanced  Severance  Program will  terminate as of February 15, 2002, and if you
are  terminated  on or after  February  16, 2002 you will  receive the  standard
severance package in accordance with existing TCK policies.

By  signing  this  agreement  you  agree to keep  the  documents  and its  terms
confidential.  After you have had the  opportunity to read and  understand  this
letter,   please  sign  and  date  the  acknowledgement   line.  Your  signature
acknowledges  that  this  communication   supersedes  any  prior  agreements  or
understandings  whether oral or written  between you and TCK  pertaining  to any
transition or incentive  payments  being  offered to you in connection  with any
termination of employment with TCK.

On  behalf  of  Thermo  Ecotek  Corporation,  I  thank  you for  your  continued
assistance  and  support.  I look  forward  to  working  with you as we meet the
challenges presented during this period of change and opportunity.







<PAGE>


If  you  have  any  questions,   regarding   anything   contained   within  this
communication,  please do not hesitate to contact either John Krupa, Director of
Human Resources or myself.

Please make a photocopy for yourself and return the original to me no later than
Wednesday, February 16, 2000.

Sincerely,



/s/ John T. Miller
-------------------------
John T. Miller
President Power Resources
Thermo Ecotek Corporation


Acknowledged and Agreed


/s/ Parimal S. Patel
-------------------------                         -------------------------
Parimal S. Patel                                            Date

<PAGE>

February 11, 2000

Mr. Parimal S. Patel
10 Gould Road
Bedford, MA 01730

Dear Parimal:

This letter confirms our discussion and outlines the Enhanced  Severance Program
which shall be offered to you in the event that your  employment  is  terminated
without  "Cause" (as defined below) or as a result of "Change in Control" of (as
defined  below) Thermo  Ecotek  Corporation  ("TCK").  The  availability  of the
Enhanced Severance Program, upon an employee's  separation,  is conditioned upon
and will  require  the  execution  of a release  of claims (a sample of which is
attached to this letter).  This  Enhanced  Severance  Program  together with the
release document will be presented and reaffirmed,  if necessary,  at that time.
If you do not execute the release of claims,  you will only receive the standard
severance  package in  accordance  with  existing TCK  policies.  This  Enhanced
Severance  Program will remain available to eligible  employees through February
15, 2002.

If you accept  employment with another entity which is a subsidiary or affiliate
of Thermo  Electron  Corporation  or TCK the Enhanced  Severance  Program  shall
become null and void.

In order to maintain eligibility for any of the below outlined elements, the TCK
requires that you remain a regular  active  employee  unless your  employment is
terminated without Cause or as a result of a Change in Control.

For  purposes  of this  Agreement,  "Cause"  shall be  determined  by TCK in the
exercise of good faith and reasonable judgement. "Cause" will include but not be
limited to,  breach of this  Agreement by you, any act by you of gross  personal
misconduct,  gross insubordination,  material  misappropriation of funds, fraud,
dishonesty,  gross  neglect  of or failure  to  perform  the  duties  reasonably
required of you pursuant to your  employment,  engaging in  activities  that are
competitive with Thermo Ecotek Corporation's business or any conduct which is in
willful  violation  of any  applicable  law or  regulation  pertaining  to TCK's
business.

"Change  of  Control"  shall  mean  the  merger,  consolidation,  reorganization
liquidation, dissolution or similar transaction entered into by TCK (except into
Thermo  Electron  Corporation),  the sale or  disposition  of 50% or more of the
existing assets of TCK in one or a series of  transactions,  change in ownership
of 50% or more of the beneficial  ownership of the outstanding  shares of common
stock of TCK. If as a result of such Change in Control you are terminated or you
are not  offered a position  with  comparable  salary,  compensation,  bonus and
benefits,  or your principal  work location is moved by more than 50 miles,  you
will be eligible for the Enhanced Severance Program.  However, if as a result of
a  Change  of  Control  you are  offered  a  position  with  comparable  salary,
compensation,  bonus and benefits and your  principal work location is not moved
by more than 50  miles,  you will not be  eligible  for the  Enhanced  Severance
Program or the standard TCK severance benefits.
<PAGE>

Notice of Termination

If your  employment  is  terminated  without Cause or as a result of a Change in
Control,  you will be notified at least 13 weeks prior to termination or receive
13 weeks pay-in-lieu-of notice, at TCK's option.

Salary Continuation

Beginning with the day following your  termination  date, you shall be placed on
salary continuation through the regular payroll system, at your regular biweekly
salary for a period of 78 weeks. TCK may, for its convenience, choose to provide
this benefit in the form of a lump sum rather than salary continuation.

Vacation

Accrued but unused  vacation  will be paid to you with the first check  covering
the salary continuation period.  Vacation payments will be calculated using your
regular  biweekly base  compensation.  You will not accrue  additional  vacation
credit beyond your termination date.

Medical, Dental, and Life Insurance

Through  the  end of your  salary  continuation  period,  you  may  continue  to
participate in any medical,  dental and/or life insurance  programs in which you
are currently  enrolled,  provided that you pay the regular  employee portion of
these benefits where  applicable.  Once medical and dental benefits  cease,  you
will be notified of your  eligibility  to continue  medical and dental  coverage
under the provisions of COBRA.

If TCK chooses to provide  the salary  continuation  benefit  through a lump sum
payment,  you will not be able to  participate  in the regular  medical,  dental
and/or life insurance programs in which you are currently enrolled. However, you
will be  immediately  eligible  under the  provisions of COBRA or the conversion
provisions of these  programs.  Should this occur,  TCK will issue to you a lump
sum payment equal to 6 months of applicable premiums.

STD and LTD

Both short term and long term disability coverage will cease as of your last day
of active employment.
<PAGE>

Employee Assistance Program

This program will  continue to be available to you and your  dependents  through
the end of your salary continuation period.

Employee Stock Purchase Plan

You will continue to be eligible for  participation  under the normal plan rules
through the end of your salary continuation period.

401K Plan

You will continue to be eligible for  participation  under the normal plan rules
through the end of your salary continuation period.

Outplacement Program

The company has arranged,  at no cost to you,  outplacement  consulting services
through  Keystone  Associates.  Keystone will  coordinate  the delivery of these
services at their offices in Burlington, Massachusetts. You shall be eligible to
begin receiving these services immediately upon termination, or you may schedule
the  start  of this  program  anytime  within  90 days  after  the  date of your
termination. The major elements of this comprehensive program include:

            Counseling

                        Resume development
                        Research skills
                        Self assessment and job targeting
                        Effective correspondence
                        Networking and other search techniques
                        Interview training


<PAGE>


      Administrative Support

Office space and private telephone line with voice mail
            Research assistance
                  Reference library

The outplacement services described above will be available for a period of four
months.

Sincerely,


/s/ John T. Miller
---------------------------
John T. Miller
Vice President
Thermo Ecotek Corporation



<PAGE>





Sample Release of Claims

In exchange for the additional  severance program offered to me by Thermo Ecotek
Corporation  in an Agreement  dated  February 11, 2000. I hereby  release Thermo
Ecotek  Corporation  and Thermo Electron  Corporation,  their  subsidiaries  and
affiliates  (collectively  the  "Corporation")  and  its  officers,   directors,
employees and legal predecessors and successors from all claims, liabilities and
causes of action,  whether known or unknown, which I have, may have, or claim to
have against the Corporation based upon or arising out of my employment with the
Corporation. I hereby agree not to file any lawsuit to assert such claims, which
include,  but are not  limited to any claims  for breach of  contract,  wrongful
termination,  or age, sex, race,  disability or other  discrimination  under the
Civil Rights Act of 1964, the Age  Discrimination  in Employment Act of 1967, or
any other federal, state, or local laws prohibiting such discrimination. As used
herein, the Corporation includes any and all parents, divisions, or subsidiaries
of the Corporation.

I understand that I have been advised to seek the advice of an attorney, if I so
choose, prior to signing this release and that I am giving up any legal claims I
have against the Corporation by signing this release.  I further understand that
I may have 21 days to consider this agreement,  that I may revoke it at any time
during the 7 days after I sign it, and that it shall not become  effective until
that 7 day revocation  period has passed. I fully understand my right to take 21
days to consider  signing  this release and,  after  having  sufficient  time to
consider my options,  I hereby waive my right to take the full 21-day period.  I
acknowledge that I am signing this release knowingly,  willingly and voluntarily
in exchange for the additional severance payment described in this letter.

I acknowledge  that I have carefully read and fully  understand  this Release of
All Claims and I have not relied on any statement, written or oral, which is not
set out in this document.




/s/ John T. Miller                                     /s/ Parimal S. Patel
-------------------------                              ------------------------
John T. Miller                                         Parimal S. Patel
Vice President
Thermo Ecotek Corporation