Document:

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                                                                    Exhibit 4.20

         THIS EMPLOYMENT AGREEMENT is effective as of the 20th day of April,
2001.

BETWEEN:

                             HYDROGENICS CORPORATION

                                 (the "Company")

                                     - and -

              RAVI GOPAL, OF THE CITY OF TORONTO, (the "Executive")

  (collectively the Company and the Executive are referred to as the "Parties")

RECITALS:

A.       The Executive has valuable skills and experience which will be of
         assistance to the Company in managing its business;

B.       The Company and the Executive desire to enter into a written Agreement
         which contains the agreed upon terms and conditions of employment.

THEREFORE, the Parties agree as follows:

1.       DUTIES AND RESPONSIBILITIES

1.1      Position

The Company appoints the Executive to the position of Vice President,
Engineering, Electronics and Control effective January 1, 2001. The Executive
will report to the Chief Executive Officer (the "CEO"). The Executive will
undertake those duties, responsibilities and reporting requirements as may be
assigned from time to time by the CEO or the Board of Directors, as applicable.

1.2      REASSIGNMENT

The Company may transfer the Executive to any affiliate, subsidiary or related
corporate entity ("Member Company" collectively, "Member Companies") with the
Executive's consent and the Executive hereby acknowledges that, in the event of
such transfer, the Executive shall draw Base Salary and benefits from such
Member Company in accordance with the terms of this Agreement, which shall
continue to apply,
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with modifications necessary to conform with comparable industry practices. If
the Executive does not consent to such a transfer, the transfer request shall be
withdrawn by the Company or the Executive may regard his employment with the
Company to have been terminated without cause and the Company will remain liable
for and shall satisfy all obligations of the Company hereunder as if the Company
had terminated the Executive without notice and without cause.

1.3      TRAVEL

The Executive shall be available for such business-related travel as may be
required for the purposes of carrying out the Executive's duties and
responsibilities.

1.4      FULL TIME AND ATTENTION

The Executive shall devote full working time and attention and shall exert best
efforts, knowledge, skill and energy to the performance of the Executive's
duties with the Company. The Executive will not, without obtaining the prior
written consent of the Company, assume any other employment or engage in any
other business or occupation or become a director, officer, employee, agent or
consultant for any other company, firm or individual while in the service of the
Company. The Executive is a fiduciary of the Company and shall act at all times
in the Company's best interests.

1.5      COMPLIANCE WITH RULES AND POLICIES

The Executive shall follow all Company rules and policies as may exist and as
are made known to the Executive from time to time.

2.       TERM OF EMPLOYMENT

The terms of this Agreement will apply to the Executive's employment with the
Company effective on April 20, 2001, and will continue until April 20, 2003,
unless otherwise terminated in accordance with the provisions of this Agreement
provided, however, that the term of this Agreement and the Executive's
employment will be automatically renewed for successive two (2) year terms
thereafter unless the Company or the Executive has given notice to the other
party at least ninety (90) days prior to the expiration of the term that the
term of this Agreement and the Executive's employment will not be so renewed.
Service time will be based on the Executive's most recent date of hire with the
Company.

3.       BASE SALARY

While in the employment of the Company, the Executive will be paid an annual
salary in the amount of $135,000, subject to employee contributions to employee
benefit plans (the "Base Salary"). The Executive's Base Salary will be payable
in accordance with Company practices and procedures as they may
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exist from time to time and in accordance with comparable industry practices.
The Base Salary will be reviewed by the Board on an annual basis and in no case
shall the Base Salary be reduced.

4.       BONUS

4.1      BONUS ELIGIBILITY

In addition to Base Salary, the Executive will also be eligible to receive a
bonus (the "Bonus"). The Bonus is entirely discretionary on the part of the
Board with each Executive Officer to be considered and assessed individually.
Under no circumstances is the Bonus to be considered part of the Executive's
Base Salary or other regular employment income.

4.2      BONUS PAYMENT

The Bonus, if any, will fall due when the Company normally pays such Bonuses,
and will be based upon the Executive's service during the preceding year. The
bonus will be paid in arrears during the month of January succeeding the year
during which it applies.

5.       BENEFITS

The Executive will be eligible to participate in the Company's Life and Health
Insurance Benefit Package normally provided to executives of the Company. Some
benefits may include compulsory employee participation and employee
contributions at levels determined by the Company. The Company regularly reviews
the Benefit Package as well as its insurance carriers, and accordingly, reserves
the right to both amend the Benefit Package and change its insurance carriers
where deemed appropriate and without further notice to the Executive.

6.       VACATION

The Executive's vacation year will be the calendar year. The Executive's annual
vacation entitlement will be 4 weeks. Vacation time not taken in any calendar
year will not be permitted to be carried over to another calendar year or any
manner accumulated. Such vacation entitlement, if any, lapses at the end of the
given calendar year. The Executive is required to arrange vacation time to suit
the essential business needs of the Company.
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7.       PERQUISITES AND EXPENSES

7.1      REIMBURSEMENT OF EXPENSES

The Company recognizes that the Executive will incur expenses in connection with
performing employment-related duties. The Company agrees to reimburse the
Executive for any reasonable out of pocket expenses incurred in the course of
employment. Reimbursement will be conditional upon the Executive providing an
itemized account and receipts, in accordance with the Company's expense policy,
as it may exist from time to time.

8.       STOCK OPTION PLANS

8.1      ELIGIBILITY

The Executive will be eligible to participate in the Company's stock option
plan, as approved by the Board and as amended from time to time (the "Stock
Option Plan"). The vesting of stock options ("Options"), and the subsequent
exercise of such Options shall be governed in all respects by the Stock Option
Plan as modified by the terms and conditions set out herein.

8.2      TERMINATION OF SERVICES OR EMPLOYMENT

For the purposes of Section 8 of this Agreement and the Company's Stock Option
Plan, the date of termination of services or employment shall be the earliest
of:

         (a)      the date on which the Executive gives notice of resignation to
                  the Company;

         (b)      the date on which the Company gives notice of termination to
                  the Executive (whether or not for Cause);

         (c)      the date of termination of employment (whether or not for
                  Cause);

         (d)      the date of expiration of the Agreement, provided that the
                  Company has given ninety (90) days' notice in accordance with
                  Article 2; or

         (e)      the date of expiration of the Agreement, provided that the
                  Executive has given ninety (90) days' notice in accordance
                  with Article 2.
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9.       TERMINATION OF EMPLOYMENT

9.1      TERMINATION WITHOUT NOTICE

The Executive's employment with the Company will be terminated, without the
Company being obligated to provide the Executive with advance notice of
termination or pay in lieu of such notice, whether under contract, statute,
common law or otherwise in the following circumstances:

         (a)      Resignation

         In the event the Executive resigns, at any time, for any reason, upon
         giving a minimum of ninety (90) days' advance written notice to the
         Company. The Executive will not be entitled to receive any further
         compensation or benefits whatsoever other than those which have accrued
         up to the Executive's last day of active service with the Company. The
         Company may, at its discretion, waive in whole or in part such notice
         in which case the Company shall pay the Executive an amount equal to
         the salary that would have been payable to the Executive and maintain
         the Benefit Package for the period from the date of termination by the
         Company until the earlier of the date of resignation selected by the
         Executive and ninety days from the date the Executive gave notice of
         resignation.

         Notwithstanding the foregoing, the Executive may resign from his
         employment with the Company immediately and thereupon will be entitled
         to the payments and rights set out in Sections 9.2(a) and (b) of this
         Agreement if:

                  (i)      the Company conducts itself in a manner that would
                           constitute a constructive dismissal of the Executive
                           as determined in accordance with common law; and

                  (ii)     the Executive resigns within one month of the conduct
                           of the Company that constitutes a constructive
                           dismissal of the Executive.

         (b)      Cause

         In the event the Executive's employment is terminated for Cause, the
         Executive will not be entitled to receive any further compensation or
         benefits whatsoever other than those which have accrued up to the date
         of termination of employment.

         For the purposes of this Agreement, the term "Cause" shall mean any
         grounds at common law for which an employer is entitled to dismiss an
         employee summarily, and includes, without limitation:

                  (i)      the Executive's breach of a material term of this
                           Agreement;
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                  (ii)     repeated and demonstrated failure on the part of the
                           Executive to perform the material duties of the
                           Executive's position in a competent manner that is
                           not cured by the Executive within ten (10) calendar
                           days of written notification thereof to the Executive
                           by the Company;

                  (iii)    conviction of the Executive for a criminal offence
                           involving fraud or dishonesty, or which otherwise
                           adversely impacts the reputation of the Company;

                  (iv)     the Executive's making personal profit out of or in
                           connection with a transaction or business opportunity
                           to which the Company is involved or otherwise
                           associated with, without making disclosure to and
                           seeking the prior written consent of the Board;

                  (v)      failure on the part of the Executive to act honestly
                           and in the best interests of the Company;

                  (vi)     failure on the part of the Executive to comply with
                           any Company rules or policies of which the Executive
                           has been apprised of a material nature that is not
                           cured within ten (10) calendar days of written
                           notification thereof to the Executive by the Company;

                  (vii)    failure on the part of the Executive to obey
                           reasonable instructions provided to the Executive in
                           the course of employment, within ten (10) calendar
                           days of receiving written notice of such disobedience
                           from the CEO; or

                  (viii)   any actions or omissions on the part of the Executive
                           constituting gross misconduct or negligence resulting
                           in material harm to the Company.

9.2      TERMINATION BY THE COMPANY WITHOUT CAUSE

         (a)      Separation Package

         Except as set out in Section 9.1, the Board by majority vote at a
         special meeting called for that purpose may terminate the Executive's
         employment at any time, without Cause and without prior notice, by
         providing the Executive with a Separation Package (the "Separation
         Package") equivalent to a lump sum payment of twenty four (24) months'
         Base Salary plus a pro rata portion of any Bonus (prorated with
         reference to the number of months the Executive has worked in the
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         year in which the termination of employment occurs (the "Months
         Worked") to an amount equal to the Bonus payable to the Executive for
         the fiscal year preceding the year in which the termination occurs,
         multiplied by a fraction, the numerator of which is Months Worked and
         the denominator of which is twelve (12)) and, in fulfillment of the
         Executive's entitlement to compensation in respect of bonus for the
         twenty four (24) month notice period, an amount equivalent to two times
         the Bonus payable to the Executive for the fiscal year preceding the
         year in which termination occurs and in any event not less than the
         amount to which the Executive would have been entitled in respect of
         bonus had he remained actively employed with the Company during the
         notice period. At the discretion of the Board, the Company may provide
         the Separation Package in twenty four (24) equal monthly payments to
         the Executive.

         (b)      Continuation of Certain Benefits

         As part of the Separation Package, the Executive will also be provided
         with a continuation of all employment related benefits for the duration
         of the twenty four (24) months from date the Executive ceases to
         provide active services to the Company (unless terminated earlier due
         to re-employment). However, subject to applicable legislation, both
         Short and Long Term Disability Benefit coverage will be discontinued
         immediately upon termination. Any benefit, including short and long
         term disability coverage, which is not continued for the duration of
         the 24 month period from the date the Executive ceases to provide
         active services to the Company shall be subject to a compensatory
         payment by the Company to the Executive in an amount equivalent to the
         cost incurred by the Executive in securing replacement coverage and in
         any event not less than the cost incurred by the Company in providing
         the benefit to the Executive. To the extent provided, continued
         coverage pursuant to the aforementioned benefit plans will be
         conditional on the Executive satisfying the terms and conditions
         required by the individual insurance policies.
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         (c)      Death

         In the event of the Executive's death, the Company will provide the
         Executive's estate with the Separation Package described in this
         Section 9.2 provided, however, that all benefits described in Section
         9.2(b) will terminate on the date of the Executive's death.

         (d)      Incapacity

         In the event the Executive is unable to perform substantially all of
         the Executive's employment related duties for a period of more than six
         (6) consecutive months during any twelve (12) month period, and if the
         incapacity of the Executive that has prevented him from performing
         substantially all of his employment related duties is likely to
         continue, the Executive's employment may be terminated by the Company,
         in which event the Company will provide him with the Separation Package
         described in this Section 9.2 in the form of a lump sum payment,
         provided, however, that the Company will provide the Executive with
         benefits under its long term disability policy throughout the period of
         incapacity following termination of employment (the "Period of
         Incapacity"), and provided further that during the Period of
         Incapacity, the Executive must meet any conditions contained in the
         applicable insurance policy.

         (e)      Non-Renewal.

         In the event of non-renewal of this Agreement by the Company, upon the
         expiration of this Agreement, the Company will provide the Executive
         with the Separation Package described in this Section 9.2.

9.3      SEPARATION PACKAGE DEEMED REASONABLE AND SUFFICIENT

         (a)      The Executive acknowledges that the Separation Package
                  provided pursuant to this Agreement supersedes and replaces
                  any and all rights to reasonable notice of termination that
                  the Executive might otherwise be entitled to at common law,
                  and the Executive expressly waives any rights to such notice.
                  The Executive agrees that the Separation Package is deemed
                  conclusively to be reasonable notice of termination and
                  specifically includes all amounts owing for termination and/or
                  severance pay under any contract, statute, common law or
                  otherwise.

         (b)      Except as set out above, the Executive will not be entitled to
                  any other salary or benefits of employment following
                  termination of employment.
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9.4      COMPANY PROPERTY

All items of any kind or nature created or used by the Executive in the course
of employment, or otherwise furnished by the Company, and all equipment, credit
cards, computers, cellular phones, data, books, records, reports, files
(including electronic files), notes, manuals, literature, software, Confidential
Information (as hereinafter defined) or any other materials belonging to the
Company or its customers, suppliers, distributors, employees, consultants or
Member Companies and in the Executive's possession or control, shall be
surrendered to the Company, in good condition, promptly upon the Executive's
termination of employment, irrespective of the time, manner or cause of
termination.

10.      CHANGE OF CONTROL

10.1     DEFINITIONS

         (a)      For the purposes of this Agreement, "Change of Control" means
                  the occurrence at any date hereafter of any of the following
                  events:

                  (i)      any change in the holding, direct or indirect, of
                  shares in the capital of the Corporation as a result of which
                  a person or group of persons acting jointly or in concert, or
                  person associated or affiliated with any such person or group
                  within the meaning of the Securities Act (Ontario), becomes
                  the beneficial owner, directly or indirectly, of shares and/or
                  other securities in excess of the number which, directly or
                  following conversion thereof, would entitle the holders
                  thereof to cast more than thirty-five percent (35%) of the
                  votes attaching to all shares of the Corporation which may be
                  cast to elect directors of the Corporation;

                  (ii)     Incumbent Directors no longer constituting a majority
                  of the Board of Directors;

                  (iii)    a sale or other disposition of all or substantially
                  all of the property or assets of the Corporation, other than
                  to an affiliate within the meaning of the Securities Act
                  (Ontario), if such affiliate offers to employ the Executive on
                  identical terms and conditions of employment which pertain to
                  the Executive as of the date of the sale or other disposition;
                  or
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                  (iv)     any determination by the majority of Incumbent
                  Directors of the Corporation that a change in control has
                  occurred or is about to occur and any such determination shall
                  be binding and conclusive for all purposes of this Agreement.

         (b)      "Incumbent Directors" shall mean those persons who are
                  directors of the Company on the date of this Agreement and
                  shall include any person who becomes a director of the Company
                  thereafter and whose election, or nomination for election, by
                  the Company's shareholders was approved by a majority of in
                  the Incumbent Directors then on the Board of Directors. This
                  approval may be by either a specific vote or by approval of
                  the proxy statement of the Company in which such person is a
                  nominee for director, without objection to such nomination.

10.2     TERMINATION IN THE EVENT OF A CHANGE OF CONTROL

In the event that the Executive's duties and responsibilities are materially
changed within twelve (12) months of the occurrence of a Change of Control, the
Executive may elect to terminate his employment and will receive the Separation
Package described in Section 9.2.

10.3     ACCELERATED VESTING

If the Executive's employment terminates in the manner described in Section 10.2
or if his employment is terminated without Cause within twelve (12) months of
the occurrence of a Change of Control, notwithstanding anything contained in the
Company's Stock Option Plan, all of the Executive's unvested Options will
immediately vest and become exercisable for ninety (90) days following the date
of termination.

11.      CONFIDENTIAL INFORMATION

11.1     ACKNOWLEDGEMENT

The Executive's employment with the Company will provide the Executive with
access to certain information relating to the Company, its customers, suppliers,
distributors, employees, consultants and Member Companies of an extremely
confidential nature (the "Confidential Information"). For the purposes of this
Agreement, Confidential Information shall include without limitation:
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         (a)      Corporate information, including agreements, contracts, plans,
                  strategies, tactics, policies, resolutions, trade name
                  applications, contractual licensing arrangements and
                  information pertaining to any ongoing litigation or
                  negotiations;

         (b)      Financial information, including cost and performance data,
                  financial statements, debt arrangements, equity structure,
                  interests, investments, real estate and holdings;

         (c)      Operational and technical information, including, trade
                  secrets, products, product specifications, know-how, formulae,
                  compositions, data, work methods, practices, improvements,
                  devices, inventions, discoveries, concepts, ideas, designs,
                  sketches, photographs, graphs, drawings, samples, research and
                  development, services, computer software, database
                  technologies, systems, structures, architectural designs and
                  all Intellectual Property as hereinafter defined;

         (d)      Marketing information, including current and planned
                  manufacturing and distribution methods, customer lists and
                  preferences, current and anticipated customer requirements,
                  price lists, market studies, sales analysis, investment plans,
                  product plans and information concerning suppliers and
                  distributors;

         (e)      Employee information, including the names and backgrounds of
                  key personnel, employee lists, resumes, personal data,
                  organizational structure, information regarding labour
                  relations, recruiting, remuneration and bonus structure,
                  performance evaluations, personnel training techniques and
                  materials; and

         (f)      Miscellaneous information, including any and all other
                  information concerning the business and affairs of the Company
                  or its Member Companies, and their customers, suppliers,
                  distributors and personnel, regardless of whether such
                  information is considered confidential under any applicable
                  legislation or at common law.

11.2     COVENANT NOT TO DISCLOSE

The Executive agrees not to disclose any Confidential Information without the
prior written consent of the Company or to make use of such information for the
Executive's personal benefit, or for the benefit of any other person, firm,
corporation or entity, except to the extent authorized in writing by the
Company.

11.3     EXCEPTIONS
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For the purposes of this Agreement, it is recognized that the Executive will not
be obligated to keep in confidence, and shall not incur any liability regarding
the disclosure or use of any Confidential Information which:

         (a)      is already in the public domain or comes into the public
                  domain without any breach of this Agreement;

         (b)      is disclosed to the Executive by a third party having
                  legitimate possession of such information and having no legal
                  obligation to maintain the confidentiality of such
                  information; or

         (c)      is required to be disclosed pursuant to applicable laws,
                  regulations, and policies or by any court or administrative
                  tribunal with jurisdiction over the Parties, provided that the
                  Executive promptly informs the Company of such a requirement
                  and assists the Company in obtaining an appropriate order
                  protecting its interests.

12.      INTELLECTUAL PROPERTY RIGHTS

12.1     INTELLECTUAL PROPERTY

The Executive agrees that all of the Executive's worldwide rights, title and
interest in any and all advances, computer programs, concepts, compositions,
data, database technologies, designs, discoveries, domain names, drawings,
formulae, ideas, improvements, integrated circuit typographies, inventions,
know-how, mask works, sketches, software, practices, processes, research
materials, trade-secrets, work methods, patents, trade-marks, copyright works
and any other intellectual property (whether registrable or not) produced, made,
composed, written, performed, or designed by the Executive, either alone or
jointly with others, during and within the scope of the Executive's employment
with the Company (the "Intellectual Property") shall vest in and be the
exclusive property of the Company.

12.2     DISCLOSURE

The Executive agrees that both during the term of this Agreement and following
termination of employment with the Company, the Executive will fully and
promptly disclose to the Company, complete details of any Intellectual Property,
with the intention that the Company shall have full knowledge and ownership of
the working and practical applications of such right.
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12.3     FULL CO-OPERATION

At the expense of the Company, the Executive shall co-operate in executing all
necessary deeds and documents and shall co-operate, at the expense of the
Company, in all other such acts and things as the Company may reasonably require
in order to vest such Intellectual Property rights in the name of the Company.

12.4     WAIVER OF PROPERTY RIGHTS

The Executive hereby waives any and all author's, moral, and proprietary rights
that the Executive may now or in the future have in any Intellectual Property
developed in the course of the Executive's employment with the Company.

13.      PROTECTION OF COMPANY INTERESTS

13.1     ACKNOWLEDGEMENT

In the course of employment with the Company, the Executive may maintain close
working relationships with the customers, clients, suppliers, distributors,
consultants, agents and employees of both the Company and its Member Companies.
Due to the sensitive nature of the Executive's position and the special access
that the Executive will have to both the Company's Confidential Information and
Intellectual Property, the Executive acknowledges that the Company may suffer
irreparable harm should the Executive breach his obligations under Section 11,
12 or Section 13.2 of this Agreement.

13.2     NON-COMPETITION/NON-SOLICITATION

The Executive will not, either while employed with the Company or for a period
of two (2) years subsequent to the Executive's termination of employment for any
reason, without the Company's express written consent, either as an individual,
or in conjunction with any other person, firm, corporation, or other entity,
whether acting as a principal, agent, employee, consultant, or in any capacity
whatsoever:

         (a)      engage in or in any way be concerned with any business or
                  enterprise engaged in the development, manufacture and sale of
                  fuel cells, or the development, manufacture and sale of fuel
                  cell systems, including but not limited to, control and test
                  equipment for fuel cells worldwide;
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         (b)      solicit any firm, person or company who is a customer, client,
                  supplier or distributor of the Company or its Member
                  Companies, in respect of products or services which are (i)
                  similar to or competitive with those of the Company or its
                  Member Companies and (ii) concerned with any business specific
                  to sub para (a) above;

         (c)      take advantage of, derive a benefit or otherwise profit from
                  any business opportunities that the Executive became aware by
                  virtue of his employment with the Company even if the Company
                  does not take advantage of or exploit such opportunities
                  except to the extent permitted by the Company in writing;

         (d)      take any unlawful action as a result of which relations
                  between the Company or its Member Companies and their
                  consultants, customers, clients, suppliers, distributors,
                  employees or others may be impaired or which might otherwise
                  be detrimental to the business interests or reputation of the
                  Company or its Member Companies;

         (e)      solicit, attempt to solicit, or communicate in any way with
                  any employees or consultants of the Company or its Member
                  Companies for the purpose of having such employees or
                  consultants leave the employ of the Company or its Member
                  Companies.

Notwithstanding the foregoing, the Executive may have an interest in a competing
business: (i) through portfolio investments in publicly listed shares or debt of
a competing business; provided the legal and beneficial interest of the
Executive is less than 9.9% of the shares or debt, respectively, of such
business; and (ii) through portfolio investments through investment
partnerships, syndicates and like pooling funds; provided the interest of the
Executive is less than 9.9% of such business' equity value or debt, as the case
may be.

13.3     VITAL CONSIDERATION

The Executive agrees that the covenants and restrictions contained in the
preceding paragraph are reasonable and valid in terms of time, scope of
activities and geographical limitations and understands and agrees that they are
vital consideration for the purposes of the Company entering into this
Agreement.

14.      SEVERABILITY

In the event that any covenant, provision or restriction contained in this
Agreement is found to be void or unenforceable (in whole or in part) by a court
of competent jurisdiction, it shall not affect or impair the
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validity of any other covenant, provisions or restrictions contained herein, nor
shall it affect the validity or enforceability of such provisions in any other
jurisdiction or in regard to other circumstances. Any covenants, provisions or
restrictions found to be void or unenforceable are declared to be separate and
distinct, and the remaining covenants, provisions and restrictions shall remain
in full force and effect.

15.      ENTIRE AGREEMENT

This Agreement constitutes the entire agreement between the Parties and
supercedes and replaces any and all other representations, understandings,
negotiations and previous agreements, written or oral, express or implied. The
Parties do not rely upon or regard as material any representations or other
agreements not specifically incorporated into and made part of this Agreement.

16.      CHANGES TO AGREEMENT

Any modifications or amendments to this Agreement must be in writing and signed
by both Parties or else they shall have no force and effect. The Parties
specifically acknowledge that continued employment of the Executive shall be
sufficient and ample consideration supporting any future modifications or
amendments to this Agreement.

17.      ENFORCEMENT

17.1     REASONABLE AND VALID

All covenants, provisions and restrictions contained in this Agreement, and
without limitation, the covenants, provisions and restrictions contained in
Articles 11, 12 and 13 are reasonable and valid, and the Executive hereby waives
all defences to the strict enforcement of such covenants, provisions and
restrictions by the Company.

17.2     SURVIVAL

Articles 11, 12 and 13 shall survive the termination of this Agreement, and the
Company's obligation to provide any Separation Package or related continuation
of benefits subsequent to the Executive's termination of employment is
conditional upon the Executive's ongoing compliance with these obligations.
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17.3     RESOLUTION OF DISPUTES

Any disputes between the Executive and the Company concerning the terms of this
Agreement except for Articles 11, 12 and 13 or the termination of Executive's
employment with the Company will be referred to final and binding arbitration in
accordance with the provisions of the Arbitration Act, 1991 (Ontario).

Where a dispute first arises, for a period of thirty (30) calendar days, the
Parties shall engage in good faith efforts to resolve the subject matter of the
dispute through negotiations. Subsequent to the expiration of this period,
should the subject matter of the dispute remain unresolved, either party may
give written notice to the other of its desire to submit such dispute to
arbitration stating with reasonable particularity the subject matter of such
dispute. The Parties shall agree upon a single arbitrator within seven (7) days
after receipt of such notice. Should the Executive and the Company not agree on
the arbitrator within thirty (30) days after written notice to arbitrate has
been provided to the other party, either party may apply (with notice) to a
judge at the Superior Court of Justice to appoint an arbitrator.

The arbitrator's decision shall be final and binding on the Executive and the
Company.

17.4     COURT RELIEF

Despite Article 17.3, the Executive acknowledges and agrees that in the event
that the Executive violates the covenants, provisions and restrictions contained
in Articles 11, 12 and 13, the Company shall be authorized and entitled to
obtain from any court of competent jurisdiction interim and permanent injunctive
relief and an accounting of all profits and benefits arising out of such
violation, which rights and remedies shall be cumulative and in addition to any
other rights, damages or remedies to which the Company might otherwise be
entitled.

17.5     COSTS

In the event of any litigation arising in respect of this Agreement, each party
shall afford its own costs, including legal fees.

18.      ENUREMENT

This Agreement shall enure to the benefit of and be binding upon the Parties and
their respective successors and assigns, including without limitation, the
Executive's heirs, executors, administrators and personal representatives.
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                                      -17-

19.      ASSIGNMENT

The Executive acknowledges that the services to be rendered pursuant to this
Agreement are unique and personal. Accordingly, the Executive may not assign any
of the Executive's rights or delegate any of the Executive's duties or
responsibilities under this Agreement. The Company may, with the consent of the
Executive, assign its rights, duties and obligations under this Agreement to a
Member Company or to a purchaser or transferee of a majority of the Company's
outstanding capital stock or to a purchaser of all, or substantially all of the
assets of the Company. The Company shall ensure that the Member Company,
purchaser, transferee or other successor agrees to be bound by the terms and
conditions of the Agreement. If the Executive does not consent to the Company's
assignment of its rights, duties and obligations under this Agreement or if a
Member Company, purchaser or transferee of a majority of the Company's
outstanding capital stock, purchaser of all, or substantially all of the assets
of the Company, or any other successor does not agree to be bound by this
Agreement, the Executive shall have no obligation to accept or submit to the
assignment of this Agreement to any Member Company, purchaser, transferee or
other successor and the Company will remain liable for and shall satisfy all
obligations of the Company hereunder as if the Company had terminated the
Executive without notice and without cause on the date upon which the Member
Company, purchaser, transferee or other successor succeeds to or is assigned the
Company's rights, duties and obligations under this Agreement. The foregoing
shall not in any way preclude the Executive's entitlement to exercise his rights
under Section 1.2 of this Agreement.

20.      LEGAL ADVICE

The Executive acknowledges that the Executive has read and understands the terms
and conditions contained in this Agreement, and that the Company has provided a
reasonable opportunity for the Executive to seek independent legal advice prior
to executing this Agreement.

21.      GOVERNING LAW

This Agreement shall be construed in accordance with the laws of the province of
Ontario.
<PAGE>   18
                                      -18-

22.      NOTICES

22.1     NOTICE TO EXECUTIVE

Any notice required or permitted to be given to the Executive shall be deemed to
have been received if delivered personally to the Executive or if mailed by
registered mail to the Executive's home address last known to the Company.

22.2     NOTICE TO COMPANY

Any notice required or permitted to be given to the Company shall be deemed to
have been received if delivered personally, mailed by registered mail to the
business address of the Company, or sent by facsimile to (905) 361-3626, in each
case addressed to the attention of the Vice President, Corporate Affairs of the
Company.

23.      CURRENCY

All dollar amounts set forth or referred to in this Agreement refer to Canadian
currency.

25.      WITHHOLDING

All payments made by the Company to the Executive or for the benefit of the
Executive shall be less applicable withholdings and deductions.

IN WITNESS OF WHICH the Parties have duly executed this Agreement:

                                          HYDROGENICS CORPORATION

                                            By: /s/ Jonathan Lundy
                                               --------------------------------
                                                 Name:  Jonathan Lundy
                                                 Title: Vice President
                                                        Corporate Affairs and
                                                        Corporate Secretary
<PAGE>   19
                                      -19-

SIGNED, SEALED & DELIVERED
In the presence of:

         /s/ Boyd Taylor                               /s/ Ravi Gopal
----------------------------------          ------------------------------------
              Witness                                    RAVI GOPAL<PAGE>   1
                                                                    Exhibit 4.21
      THIS EMPLOYMENT AGREEMENT is effective as of the 20th day of April, 2001.

BETWEEN:

                             HYDROGENICS CORPORATION

                                 (the "Company")

                                     - and -

         JOSEPH CARGNELLI, OF THE CITY OF TORONTO, (the "Executive")

(collectively the Company and the Executive are referred to as the "Parties")

RECITALS:

A.    The Executive has valuable skills and experience which will be of
      assistance to the Company in managing its business;

B.    The Company and the Executive desire to enter into a written Agreement
      which contains the agreed upon terms and conditions of employment.

THEREFORE, the Parties agree as follows:

1.    DUTIES AND RESPONSIBILITIES

1.1   Position

The Company appoints the Executive to the position of Vice President,
Engineering effective January 1, 2001. The Executive will report to the Chief
Executive Officer (the "CEO"). The Executive will undertake those duties,
responsibilities and reporting requirements as may be assigned from time to time
by the CEO or the Board of Directors, as applicable.

1.2   REASSIGNMENT

The Company may transfer the Executive to any affiliate, subsidiary or related
corporate entity ("Member Company" collectively, "Member Companies") with the
Executive's consent and the Executive hereby acknowledges that, in the event of
such transfer, the Executive shall draw Base Salary and benefits from such
Member Company in accordance with the terms of this Agreement, which shall
continue to apply,
<PAGE>   2
                                      -2-

with modifications necessary to conform with comparable industry practices. If
the Executive does not consent to such a transfer, the transfer request shall be
withdrawn by the Company or the Executive may regard his employment with the
Company to have been terminated without cause and the Company will remain liable
for and shall satisfy all obligations of the Company hereunder as if the Company
had terminated the Executive without notice and without cause.

1.3   TRAVEL

The Executive shall be available for such business-related travel as may be
required for the purposes of carrying out the Executive's duties and
responsibilities.

1.4   FULL TIME AND ATTENTION

The Executive shall devote full working time and attention and shall exert best
efforts, knowledge, skill and energy to the performance of the Executive's
duties with the Company. The Executive will not, without obtaining the prior
written consent of the Company, assume any other employment or engage in any
other business or occupation or become a director, officer, employee, agent or
consultant for any other company, firm or individual while in the service of the
Company. The Executive is a fiduciary of the Company and shall act at all times
in the Company's best interests.

1.5   COMPLIANCE WITH RULES AND POLICIES

The Executive shall follow all Company rules and policies as may exist and as
are made known to the Executive from time to time.

2.    TERM OF EMPLOYMENT

The terms of this Agreement will apply to the Executive's employment with the
Company effective on April 20, 2001, and will continue until April 20, 2003,
unless otherwise terminated in accordance with the provisions of this Agreement
provided, however, that the term of this Agreement and the Executive's
employment will be automatically renewed for successive two (2) year terms
thereafter unless the Company or the Executive has given notice to the other
party at least ninety (90) days prior to the expiration of the term that the
term of this Agreement and the Executive's employment will not be so renewed.
Service time will be based on the Executive's most recent date of hire with the
Company.

3.    BASE SALARY

While in the employment of the Company, the Executive will be paid an annual
salary in the amount of $135,000, subject to employee contributions to employee
benefit plans (the "Base Salary"). The Executive's Base Salary will be payable
in accordance with Company practices and procedures as they may
<PAGE>   3
                                      -3-

exist from time to time and in accordance with comparable industry practices.
The Base Salary will be reviewed by the Board on an annual basis and in no case
shall the Base Salary be reduced.

4.    BONUS

4.1   BONUS ELIGIBILITY

In addition to Base Salary, the Executive will also be eligible to receive a
bonus (the "Bonus"). The Bonus is entirely discretionary on the part of the
Board with each Executive Officer to be considered and assessed individually.
Under no circumstances is the Bonus to be considered part of the Executive's
Base Salary or other regular employment income.

4.2   BONUS PAYMENT

The Bonus, if any, will fall due when the Company normally pays such Bonuses,
and will be based upon the Executive's service during the preceding year. The
bonus will be paid in arrears during the month of January succeeding the year
during which it applies.

5.    BENEFITS

The Executive will be eligible to participate in the Company's Life and Health
Insurance Benefit Package normally provided to executives of the Company. Some
benefits may include compulsory employee participation and employee
contributions at levels determined by the Company. The Company regularly reviews
the Benefit Package as well as its insurance carriers, and accordingly, reserves
the right to both amend the Benefit Package and change its insurance carriers
where deemed appropriate and without further notice to the Executive.

6.    VACATION

The Executive's vacation year will be the calendar year. The Executive's annual
vacation entitlement will be 4 weeks. Vacation time not taken in any calendar
year will not be permitted to be carried over to another calendar year or any
manner accumulated. Such vacation entitlement, if any, lapses at the end of the
given calendar year. The Executive is required to arrange vacation time to suit
the essential business needs of the Company.
<PAGE>   4
                                      -4-

7.    PERQUISITES AND EXPENSES

7.1   REIMBURSEMENT OF EXPENSES

The Company recognizes that the Executive will incur expenses in connection with
performing employment-related duties. The Company agrees to reimburse the
Executive for any reasonable out of pocket expenses incurred in the course of
employment. Reimbursement will be conditional upon the Executive providing an
itemized account and receipts, in accordance with the Company's expense policy,
as it may exist from time to time.

8.    STOCK OPTION PLANS

8.1   ELIGIBILITY

The Executive will be eligible to participate in the Company's stock option
plan, as approved by the Board and as amended from time to time (the "Stock
Option Plan"). The vesting of stock options ("Options"), and the subsequent
exercise of such Options shall be governed in all respects by the Stock Option
Plan as modified by the terms and conditions set out herein.

8.2   TERMINATION OF SERVICES OR EMPLOYMENT

For the purposes of Section 8 of this Agreement and the Company's Stock Option
Plan, the date of termination of services or employment shall be the earliest
of:

      (a)   the date on which the Executive gives notice of resignation to
            the Company;

      (b)   the date on which the Company gives notice of termination to the
            Executive (whether or not for Cause);

      (c)   the date of termination of employment (whether or not for Cause);

      (d)   the date of expiration of the Agreement, provided that the Company
            has given ninety (90) days' notice in accordance with Article 2; or

      (e)   the date of expiration of the Agreement, provided that the Executive
            has given ninety (90) days' notice in accordance with Article 2.
<PAGE>   5
                                      -5-

9.    TERMINATION OF EMPLOYMENT

9.1   TERMINATION WITHOUT NOTICE

The Executive's employment with the Company will be terminated, without the
Company being obligated to provide the Executive with advance notice of
termination or pay in lieu of such notice, whether under contract, statute,
common law or otherwise in the following circumstances:

      (a)   Resignation

      In the event the Executive resigns, at any time, for any reason, upon
      giving a minimum of ninety (90) days' advance written notice to the
      Company. The Executive will not be entitled to receive any further
      compensation or benefits whatsoever other than those which have accrued up
      to the Executive's last day of active service with the Company. The
      Company may, at its discretion, waive in whole or in part such notice in
      which case the Company shall pay the Executive an amount equal to the
      salary that would have been payable to the Executive and maintain the
      Benefit Package for the period from the date of termination by the Company
      until the earlier of the date of resignation selected by the Executive and
      ninety days from the date the Executive gave notice of resignation.

      Notwithstanding the foregoing, the Executive may resign from his
      employment with the Company immediately and thereupon will be entitled to
      the payments and rights set out in Sections 9.2(a) and (b) of this
      Agreement if:

            (i)   the Company conducts itself in a manner that would constitute
                  a constructive dismissal of the Executive as determined in
                  accordance with common law; and

            (ii)  the Executive resigns within one month of the conduct of the
                  Company that constitutes a constructive dismissal of the
                  Executive.

      (b)   Cause

      In the event the Executive's employment is terminated for Cause, the
      Executive will not be entitled to receive any further compensation or
      benefits whatsoever other than those which have accrued up to the date of
      termination of employment.

      For the purposes of this Agreement, the term "Cause" shall mean any
      grounds at common law for which an employer is entitled to dismiss an
      employee summarily, and includes, without limitation:

             (i)  the Executive's breach of a material term of this Agreement;
<PAGE>   6
                                      -6-

             (ii) repeated and demonstrated failure on the part of the Executive
                  to perform the material duties of the Executive's position in
                  a competent manner that is not cured by the Executive within
                  ten (10) calendar days of written notification thereof to the
                  Executive by the Company;

             (iii) conviction of the Executive for a criminal offence involving
                  fraud or dishonesty, or which otherwise adversely impacts the
                  reputation of the Company;

             (iv) the Executive's making personal profit out of or in connection
                  with a transaction or business opportunity to which the
                  Company is involved or otherwise associated with, without
                  making disclosure to and seeking the prior written consent of
                  the Board;

             (v)  failure on the part of the Executive to act honestly and in
                  the best interests of the Company;

             (vi) failure on the part of the Executive to comply with any
                  Company rules or policies of which the Executive has been
                  apprised of a material nature that is not cured within ten
                  (10) calendar days of written notification thereof to the
                  Executive by the Company;

             (vii) failure on the part of the Executive to obey reasonable
                  instructions provided to the Executive in the course of
                  employment, within ten (10) calendar days of receiving written
                  notice of such disobedience from the CEO; or

             (viii) any actions or omissions on the part of the Executive
                  constituting gross misconduct or negligence resulting in
                  material harm to the Company.

9.2   TERMINATION BY THE COMPANY WITHOUT CAUSE

      (a)   Separation Package

      Except as set out in Section 9.1, the Board by majority vote at a special
      meeting called for that purpose may terminate the Executive's employment
      at any time, without Cause and without prior notice, by providing the
      Executive with a Separation Package (the "Separation Package") equivalent
      to a lump sum payment of twenty four (24) months' Base Salary plus a pro
      rata portion of any Bonus (prorated with reference to the number of months
      the Executive has worked in the
<PAGE>   7
                                      -7-

      year in which the termination of employment occurs (the "Months Worked")
      to an amount equal to the Bonus payable to the Executive for the fiscal
      year preceding the year in which the termination occurs, multiplied by a
      fraction, the numerator of which is Months Worked and the denominator of
      which is twelve (12)) and, in fulfillment of the Executive's entitlement
      to compensation in respect of bonus for the twenty four (24) month notice
      period, an amount equivalent to two times the Bonus payable to the
      Executive for the fiscal year preceding the year in which termination
      occurs and in any event not less than the amount to which the Executive
      would have been entitled in respect of bonus had he remained actively
      employed with the Company during the notice period. At the discretion of
      the Board, the Company may provide the Separation Package in twenty four
      (24) equal monthly payments to the Executive.

      (b)   Continuation of Certain Benefits

      As part of the Separation Package, the Executive will also be provided
      with a continuation of all employment related benefits for the duration of
      the twenty four (24) months from date the Executive ceases to provide
      active services to the Company (unless terminated earlier due to
      re-employment). However, subject to applicable legislation, both Short and
      Long Term Disability Benefit coverage will be discontinued immediately
      upon termination. Any benefit, including short and long term disability
      coverage, which is not continued for the duration of the 24 month period
      from the date the Executive ceases to provide active services to the
      Company shall be subject to a compensatory payment by the Company to the
      Executive in an amount equivalent to the cost incurred by the Executive in
      securing replacement coverage and in any event not less than the cost
      incurred by the Company in providing the benefit to the Executive. To the
      extent provided, continued coverage pursuant to the aforementioned benefit
      plans will be conditional on the Executive satisfying the terms and
      conditions required by the individual insurance policies.
<PAGE>   8
                                      -8-

      (c)   Death

      In the event of the Executive's death, the Company will provide the
      Executive's estate with the Separation Package described in this Section
      9.2 provided, however, that all benefits described in Section 9.2(b) will
      terminate on the date of the Executive's death.

      (d)   Incapacity

      In the event the Executive is unable to perform substantially all of the
      Executive's employment related duties for a period of more than six (6)
      consecutive months during any twelve (12) month period, and if the
      incapacity of the Executive that has prevented him from performing
      substantially all of his employment related duties is likely to continue,
      the Executive's employment may be terminated by the Company, in which
      event the Company will provide him with the Separation Package described
      in this Section 9.2 in the form of a lump sum payment, provided, however,
      that the Company will provide the Executive with benefits under its long
      term disability policy throughout the period of incapacity following
      termination of employment (the "Period of Incapacity"), and provided
      further that during the Period of Incapacity, the Executive must meet any
      conditions contained in the applicable insurance policy.

      (e)   Non-Renewal.

      In the event of non-renewal of this Agreement by the Company, upon the
      expiration of this Agreement, the Company will provide the Executive with
      the Separation Package described in this Section 9.2.

9.3   SEPARATION PACKAGE DEEMED REASONABLE AND SUFFICIENT

      (a)   The Executive acknowledges that the Separation Package provided
            pursuant to this Agreement supersedes and replaces any and all
            rights to reasonable notice of termination that the Executive
            might otherwise be entitled to at common law, and the Executive
            expressly waives any rights to such notice.  The Executive agrees
            that the Separation Package is deemed conclusively to be
            reasonable notice of termination and specifically includes all
            amounts owing for termination and/or severance pay under any
            contract, statute, common law or otherwise.

      (b)   Except as set out above, the Executive will not be entitled to any
            other salary or benefits of employment following termination of
            employment.
<PAGE>   9
                                      -9-

9.4   COMPANY PROPERTY

All items of any kind or nature created or used by the Executive in the course
of employment, or otherwise furnished by the Company, and all equipment, credit
cards, computers, cellular phones, data, books, records, reports, files
(including electronic files), notes, manuals, literature, software, Confidential
Information (as hereinafter defined) or any other materials belonging to the
Company or its customers, suppliers, distributors, employees, consultants or
Member Companies and in the Executive's possession or control, shall be
surrendered to the Company, in good condition, promptly upon the Executive's
termination of employment, irrespective of the time, manner or cause of
termination.

10.   CHANGE OF CONTROL

10.1  DEFINITIONS

      (a)   For the purposes of this Agreement, "Change of Control" means the
            occurrence at any date hereafter of any of the following events:

            (i) any change in the holding, direct or indirect, of shares in the
            capital of the Corporation as a result of which a person or group of
            persons acting jointly or in concert, or person associated or
            affiliated with any such person or group within the meaning of the
            Securities Act (Ontario), becomes the beneficial owner, directly or
            indirectly, of shares and/or other securities in excess of the
            number which, directly or following conversion thereof, would
            entitle the holders thereof to cast more than thirty-five percent
            (35%) of the votes attaching to all shares of the Corporation which
            may be cast to elect directors of the Corporation;

            (ii)  Incumbent Directors no longer constituting a majority of
            the Board of Directors;

            (iii) a sale or other disposition of all or substantially all of the
            property or assets of the Corporation, other than to an affiliate
            within the meaning of the Securities Act (Ontario), if such
            affiliate offers to employ the Executive on identical terms and
            conditions of employment which pertain to the Executive as of the
            date of the sale or other disposition; or
<PAGE>   10
                                      -10-

            (iv) any determination by the majority of Incumbent Directors of the
            Corporation that a change in control has occurred or is about to
            occur and any such determination shall be binding and conclusive for
            all purposes of this Agreement.

      (b)   "Incumbent Directors" shall mean those persons who are directors
            of the Company on the date of this Agreement and shall include
            any person who becomes a director of the Company thereafter and
            whose election, or nomination for election, by the Company's
            shareholders was approved by a majority of in the Incumbent
            Directors then on the Board of Directors.  This approval may be
            by either a specific vote or by approval of the proxy statement
            of the Company in which such person is a nominee for director,
            without objection to such nomination.

10.2  TERMINATION IN THE EVENT OF A CHANGE OF CONTROL

In the event that the Executive's duties and responsibilities are materially
changed within twelve (12) months of the occurrence of a Change of Control, the
Executive may elect to terminate his employment and will receive the Separation
Package described in Section 9.2.

10.3  ACCELERATED VESTING

If the Executive's employment terminates in the manner described in Section 10.2
or if his employment is terminated without Cause within twelve (12) months of
the occurrence of a Change of Control, notwithstanding anything contained in the
Company's Stock Option Plan, all of the Executive's unvested Options will
immediately vest and become exercisable for ninety (90) days following the date
of termination.

11.   CONFIDENTIAL INFORMATION

11.1  ACKNOWLEDGEMENT

The Executive's employment with the Company will provide the Executive with
access to certain information relating to the Company, its customers, suppliers,
distributors, employees, consultants and Member Companies of an extremely
confidential nature (the "Confidential Information"). For the purposes of this
Agreement, Confidential Information shall include without limitation:
<PAGE>   11
                                      -11-

      (a)   Corporate information, including agreements, contracts, plans,
            strategies, tactics, policies, resolutions, trade name applications,
            contractual licensing arrangements and information pertaining to any
            ongoing litigation or negotiations;

      (b)   Financial information, including cost and performance data,
            financial statements, debt arrangements, equity structure,
            interests, investments, real estate and holdings;

      (c)   Operational and technical information, including, trade secrets,
            products, product specifications, know-how, formulae, compositions,
            data, work methods, practices, improvements, devices, inventions,
            discoveries, concepts, ideas, designs, sketches, photographs,
            graphs, drawings, samples, research and development, services,
            computer software, database technologies, systems, structures,
            architectural designs and all Intellectual Property as hereinafter
            defined;

      (d)   Marketing information, including current and planned manufacturing
            and distribution methods, customer lists and preferences, current
            and anticipated customer requirements, price lists, market studies,
            sales analysis, investment plans, product plans and information
            concerning suppliers and distributors;

      (e)   Employee information, including the names and backgrounds of key
            personnel, employee lists, resumes, personal data, organizational
            structure, information regarding labour relations, recruiting,
            remuneration and bonus structure, performance evaluations, personnel
            training techniques and materials; and

      (f)   Miscellaneous information, including any and all other information
            concerning the business and affairs of the Company or its Member
            Companies, and their customers, suppliers, distributors and
            personnel, regardless of whether such information is considered
            confidential under any applicable legislation or at common law.

11.2  COVENANT NOT TO DISCLOSE

The Executive agrees not to disclose any Confidential Information without the
prior written consent of the Company or to make use of such information for the
Executive's personal benefit, or for the benefit of any other person, firm,
corporation or entity, except to the extent authorized in writing by the
Company.

11.3  EXCEPTIONS
<PAGE>   12
                                      -12-

For the purposes of this Agreement, it is recognized that the Executive will not
be obligated to keep in confidence, and shall not incur any liability regarding
the disclosure or use of any Confidential Information which:

      (a)   is already in the public domain or comes into the public domain
            without any breach of this Agreement;

      (b)   is disclosed to the Executive by a third party having legitimate
            possession of such information and having no legal obligation to
            maintain the confidentiality of such information; or

      (c)   is required to be disclosed pursuant to applicable laws,
            regulations, and policies or by any court or administrative tribunal
            with jurisdiction over the Parties, provided that the Executive
            promptly informs the Company of such a requirement and assists the
            Company in obtaining an appropriate order protecting its interests.

12.   INTELLECTUAL PROPERTY RIGHTS

12.1  INTELLECTUAL PROPERTY

The Executive agrees that all of the Executive's worldwide rights, title and
interest in any and all advances, computer programs, concepts, compositions,
data, database technologies, designs, discoveries, domain names, drawings,
formulae, ideas, improvements, integrated circuit typographies, inventions,
know-how, mask works, sketches, software, practices, processes, research
materials, trade-secrets, work methods, patents, trade-marks, copyright works
and any other intellectual property (whether registrable or not) produced, made,
composed, written, performed, or designed by the Executive, either alone or
jointly with others, during and within the scope of the Executive's employment
with the Company (the "Intellectual Property") shall vest in and be the
exclusive property of the Company.

12.2  DISCLOSURE

The Executive agrees that both during the term of this Agreement and following
termination of employment with the Company, the Executive will fully and
promptly disclose to the Company, complete details of any Intellectual Property,
with the intention that the Company shall have full knowledge and ownership of
the working and practical applications of such right.
<PAGE>   13
                                      -13-

12.3  FULL CO-OPERATION

At the expense of the Company, the Executive shall co-operate in executing all
necessary deeds and documents and shall co-operate, at the expense of the
Company, in all other such acts and things as the Company may reasonably require
in order to vest such Intellectual Property rights in the name of the Company.

12.4  WAIVER OF PROPERTY RIGHTS

The Executive hereby waives any and all author's, moral, and proprietary rights
that the Executive may now or in the future have in any Intellectual Property
developed in the course of the Executive's employment with the Company.

13.   PROTECTION OF COMPANY INTERESTS

13.1  ACKNOWLEDGEMENT

In the course of employment with the Company, the Executive may maintain close
working relationships with the customers, clients, suppliers, distributors,
consultants, agents and employees of both the Company and its Member Companies.
Due to the sensitive nature of the Executive's position and the special access
that the Executive will have to both the Company's Confidential Information and
Intellectual Property, the Executive acknowledges that the Company may suffer
irreparable harm should the Executive breach his obligations under Section 11,
12 or Section 13.2 of this Agreement.

13.2  NON-COMPETITION/NON-SOLICITATION

The Executive will not, either while employed with the Company or for a period
of two (2) years subsequent to the Executive's termination of employment for any
reason, without the Company's express written consent, either as an individual,
or in conjunction with any other person, firm, corporation, or other entity,
whether acting as a principal, agent, employee, consultant, or in any capacity
whatsoever:

      (a)   engage in or in any way be concerned with any business or enterprise
            engaged in the development, manufacture and sale of fuel cells, or
            the development, manufacture and sale of fuel cell systems,
            including but not limited to, control and test equipment for fuel
            cells worldwide;
<PAGE>   14
                                      -14-

      (b)   solicit any firm, person or company who is a customer, client,
            supplier or distributor of the Company or its Member Companies, in
            respect of products or services which are (i) similar to or
            competitive with those of the Company or its Member Companies and
            (ii) concerned with any business specific to sub para (a) above;

      (c)   take advantage of, derive a benefit or otherwise profit from any
            business opportunities that the Executive became aware by virtue of
            his employment with the Company even if the Company does not take
            advantage of or exploit such opportunities except to the extent
            permitted by the Company in writing;

      (d)   take any unlawful action as a result of which relations between the
            Company or its Member Companies and their consultants, customers,
            clients, suppliers, distributors, employees or others may be
            impaired or which might otherwise be detrimental to the business
            interests or reputation of the Company or its Member Companies;

      (e)   solicit, attempt to solicit, or communicate in any way with any
            employees or consultants of the Company or its Member Companies for
            the purpose of having such employees or consultants leave the employ
            of the Company or its Member Companies.

Notwithstanding the foregoing, the Executive may have an interest in a competing
business: (i) through portfolio investments in publicly listed shares or debt of
a competing business; provided the legal and beneficial interest of the
Executive is less than 9.9% of the shares or debt, respectively, of such
business; and (ii) through portfolio investments through investment
partnerships, syndicates and like pooling funds; provided the interest of the
Executive is less than 9.9% of such business' equity value or debt, as the case
may be.

13.3  VITAL CONSIDERATION

The Executive agrees that the covenants and restrictions contained in the
preceding paragraph are reasonable and valid in terms of time, scope of
activities and geographical limitations and understands and agrees that they are
vital consideration for the purposes of the Company entering into this
Agreement.

14.   SEVERABILITY

In the event that any covenant, provision or restriction contained in this
Agreement is found to be void or unenforceable (in whole or in part) by a court
of competent jurisdiction, it shall not affect or impair the
<PAGE>   15
                                      -15-

validity of any other covenant, provisions or restrictions contained herein, nor
shall it affect the validity or enforceability of such provisions in any other
jurisdiction or in regard to other circumstances. Any covenants, provisions or
restrictions found to be void or unenforceable are declared to be separate and
distinct, and the remaining covenants, provisions and restrictions shall remain
in full force and effect.

15.   ENTIRE AGREEMENT

This Agreement constitutes the entire agreement between the Parties and
supercedes and replaces any and all other representations, understandings,
negotiations and previous agreements, written or oral, express or implied. The
Parties do not rely upon or regard as material any representations or other
agreements not specifically incorporated into and made part of this Agreement.

16.   CHANGES TO AGREEMENT

Any modifications or amendments to this Agreement must be in writing and signed
by both Parties or else they shall have no force and effect. The Parties
specifically acknowledge that continued employment of the Executive shall be
sufficient and ample consideration supporting any future modifications or
amendments to this Agreement.

17.   ENFORCEMENT

17.1  REASONABLE AND VALID

All covenants, provisions and restrictions contained in this Agreement, and
without limitation, the covenants, provisions and restrictions contained in
Articles 11, 12 and 13 are reasonable and valid, and the Executive hereby waives
all defences to the strict enforcement of such covenants, provisions and
restrictions by the Company.

17.2  SURVIVAL

Articles 11, 12 and 13 shall survive the termination of this Agreement, and the
Company's obligation to provide any Separation Package or related continuation
of benefits subsequent to the Executive's termination of employment is
conditional upon the Executive's ongoing compliance with these obligations.
<PAGE>   16
                                      -16-

17.3  RESOLUTION OF DISPUTES

Any disputes between the Executive and the Company concerning the terms of this
Agreement except for Articles 11, 12 and 13 or the termination of Executive's
employment with the Company will be referred to final and binding arbitration in
accordance with the provisions of the Arbitration Act, 1991 (Ontario).

Where a dispute first arises, for a period of thirty (30) calendar days, the
Parties shall engage in good faith efforts to resolve the subject matter of the
dispute through negotiations. Subsequent to the expiration of this period,
should the subject matter of the dispute remain unresolved, either party may
give written notice to the other of its desire to submit such dispute to
arbitration stating with reasonable particularity the subject matter of such
dispute. The Parties shall agree upon a single arbitrator within seven (7) days
after receipt of such notice. Should the Executive and the Company not agree on
the arbitrator within thirty (30) days after written notice to arbitrate has
been provided to the other party, either party may apply (with notice) to a
judge at the Superior Court of Justice to appoint an arbitrator.

The arbitrator's decision shall be final and binding on the Executive and the
Company.

17.4  COURT RELIEF

Despite Article 17.3, the Executive acknowledges and agrees that in the event
that the Executive violates the covenants, provisions and restrictions contained
in Articles 11, 12 and 13, the Company shall be authorized and entitled to
obtain from any court of competent jurisdiction interim and permanent injunctive
relief and an accounting of all profits and benefits arising out of such
violation, which rights and remedies shall be cumulative and in addition to any
other rights, damages or remedies to which the Company might otherwise be
entitled.

17.5  COSTS

In the event of any litigation arising in respect of this Agreement, each party
shall afford its own costs, including legal fees.

18.   ENUREMENT

This Agreement shall enure to the benefit of and be binding upon the Parties and
their respective successors and assigns, including without limitation, the
Executive's heirs, executors, administrators and personal representatives.
<PAGE>   17
                                      -17-

19.   ASSIGNMENT

The Executive acknowledges that the services to be rendered pursuant to this
Agreement are unique and personal. Accordingly, the Executive may not assign any
of the Executive's rights or delegate any of the Executive's duties or
responsibilities under this Agreement. The Company may, with the consent of the
Executive, assign its rights, duties and obligations under this Agreement to a
Member Company or to a purchaser or transferee of a majority of the Company's
outstanding capital stock or to a purchaser of all, or substantially all of the
assets of the Company. The Company shall ensure that the Member Company,
purchaser, transferee or other successor agrees to be bound by the terms and
conditions of the Agreement. If the Executive does not consent to the Company's
assignment of its rights, duties and obligations under this Agreement or if a
Member Company, purchaser or transferee of a majority of the Company's
outstanding capital stock, purchaser of all, or substantially all of the assets
of the Company, or any other successor does not agree to be bound by this
Agreement, the Executive shall have no obligation to accept or submit to the
assignment of this Agreement to any Member Company, purchaser, transferee or
other successor and the Company will remain liable for and shall satisfy all
obligations of the Company hereunder as if the Company had terminated the
Executive without notice and without cause on the date upon which the Member
Company, purchaser, transferee or other successor succeeds to or is assigned the
Company's rights, duties and obligations under this Agreement. The foregoing
shall not in any way preclude the Executive's entitlement to exercise his rights
under Section 1.2 of this Agreement.

20.   LEGAL ADVICE

The Executive acknowledges that the Executive has read and understands the terms
and conditions contained in this Agreement, and that the Company has provided a
reasonable opportunity for the Executive to seek independent legal advice prior
to executing this Agreement.

21.   GOVERNING LAW

This Agreement shall be construed in accordance with the laws of the province of
Ontario.
<PAGE>   18
                                      -18-

22.   NOTICES

22.1  NOTICE TO EXECUTIVE

Any notice required or permitted to be given to the Executive shall be deemed to
have been received if delivered personally to the Executive or if mailed by
registered mail to the Executive's home address last known to the Company.

22.2  NOTICE TO COMPANY

Any notice required or permitted to be given to the Company shall be deemed to
have been received if delivered personally, mailed by registered mail to the
business address of the Company, or sent by facsimile to (905) 361-3626, in each
case addressed to the attention of the Vice President, Corporate Affairs of the
Company.

23.   CURRENCY

All dollar amounts set forth or referred to in this Agreement refer to Canadian
currency.

25.   WITHHOLDING

All payments made by the Company to the Executive or for the benefit of the
Executive shall be less applicable withholdings and deductions.

IN WITNESS OF WHICH the Parties have duly executed this Agreement:

                                         HYDROGENICS CORPORATION

                                          By: /s/ Jonathan Lundy
                                             __________________________________
                                              Name:  Jonathan Lundy
                                              Title: Vice President
                                                     Corporate Affairs and
                                                     Corporate Secretary
<PAGE>   19
                                      -19-

SIGNED, SEALED & DELIVERED
In the presence of:

         /s/ David Frank                             /s/ Joseph Cargnelli
_______________________________              ___________________________________
            Witness                                    JOSEPH CARGNELLI

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