<PAGE>
 
                                  FORM 10-K/A



                      SECURITIES AND EXCHANGE COMMISSION
                            Washington, D.C.  20549


[X]  ANNUAL REPORT PURSUANT TO SECTION 13 or 15(d) OF THE SECURITIES EXCHANGE
     ACT OF 1934

For the fiscal year ended December 31, 1998

                              OR

[_]  TRANSITION REPORT PURSUANT TO SECTION 13 or 15(d) OF THE SECURITIES
     EXCHANGE ACT OF 1934


For the transition period from               to 
--------------------------------------------    -------------             
Commission File Number 1-12554


                 COMPANIA BOLIVIANA DE ENERGIA ELECTRICA, S.A.
                        BOLIVIAN POWER COMPANY LIMITED
             -----------------------------------------------------
          (Exact Name of the Registrant as Specified in its Charter)



Nova Scotia                                                           13-2691133
----------------------------                          --------------------------
(State or other jurisdiction of                                 (I.R.S. Employer
incorporation or organization)                               Identification No.)

                              Av. Hernando Siles 5635
                              Obrajes, La Paz-Bolivia
                              -----------------------

              (Address of principal executive offices)(zip code)


Registrant's telephone numbers, including area codes:


                               (Bolivia) 591-2-782474
                               ----------------------


Securities registered pursuant to Section 12(b) of the Act:


Title of each class     Name of each exchange on which registered


  None                  Not applicable

  Securities registered pursuant to section 12(g) of the Act:


                          Common Shares, No Par Value
                          ---------------------------
                               (Title of Class)



Indicate by check mark whether the Registrant (1) has filed all reports required
to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during
the preceding 12 months (or for such shorter period that the Registrant was
required to file such reports), and (2) has been subject to such filing
requirements for the past 90 days.  YES   X    NO 
                                        -----     -----     


  Indicate by check mark if disclosure of delinquent filers pursuant to Item 405
of Regulation S-K is not contained herein, and will not be contained, to the
best of Registrant's knowledge, in definitive proxy or information statements
incorporated by reference in Part III of this Form 10-K or any amendment to this
Form 10-K.  YES   X    NO 
                -----     -----     
<PAGE>
 
  The Registrant's Common Stock was delisted from the New York Stock Exchange on
December 19, 1996.  At that time, the aggregate market value of the Registrant's
Common Stock held by non-affiliates was approximately $6,100,000.  Since then,
there has been no established active trading market for the Registrant's Common
Stock.  The Registrant is not able to estimate the current aggregate market
value of the Registrant's Common Stock held by non-affiliates since it has no
information concerning recent trading prices.

  As of March 22, 1999, there were 4,202,575 outstanding shares of the
Registrant's Common Stock, no par value.

  This filing on Form 10-K/A No. 1 amends the Annual Report on Form 10-K for the
fiscal year ended December 31, 1998, of Compania Boliviana de Energia Electrica
S.A. - Bolivian Power Company Limited (the "Company").  The undersigned
Registrant hereby amends the following items, financial statements, exhibits or
other portions of its report on Form 10-K for the fiscal year ended December 31,
1998 (the "Form 10-K"), as set forth below:


The following items are hereby amended and restated to read in their entirety as
they appear in this amendment.

                              Part III

Item 10.  Directors and Executive Officers of the Registrant

Item 11.  Executive Compensation

Item 12.  Security Ownership of Certain Beneficial Owners and Management

Item 13.  Certain Relationships and Related Transactions

                                       2
<PAGE>
 
Item 10.  Directors and Executive Officers of the Registrant
 
 
                                      DIRECTOR
                                      OR OFFICER        POSITION WITH
NAME                       AGE        SINCE             THE COMPANY
----                       ---        ----------        -----------
 
David H. Peterson           58        1996              Chairman of the Board,
                                                        Chief Executive Officer
                                                        and Director
 
Roger J. Dupuis             57        1993              President and General
                                                        Manager
 
Roland C. Gibson            47        1991              Vice President - Finance
 
Mats Fagerlund              48        1998              Director
 
Mauricio Gonzalez           42        1996              Director
 
Leonard Bluhm               53        1997              Director
 
Hans Lundgren               49        1998              Director
 
Gunnar Vallin               55        1997              Director
 
Ronald J. Will              59        1996              Director
 
Edwin G. Corr               64        1994              Director

All officers serve at the pleasure of the Board of Directors of the Company.

The recent business experience of the Company's executive officers and directors
is summarized as follows:

David H. Peterson.  Mr. Peterson has been the Company's Chairman of the Board
since December 1996.  He served as its Chief Executive Officer from December
1996 until November 1997.  He has been Chairman of the Board of NRG Energy, Inc.
("NRG") since January 1994, Chief Executive Officer of NRG since November 1993,
President of NRG since 1989 and a Director of NRG since 1989.  He is also
Chairman of the Board of Directors of Cogeneration Corporation of America
("CogenAmerica").  He was also Chief Operating Officer of NRG from June 1992 to
November 1993.  Prior to joining NRG, Mr. Peterson was Vice President, Non -
Regulated Generation for Northern States Power Company ("NSP") and has served in
various other management positions with NSP during the last 20 years.

Roger J. Dupuis.  Mr. Dupuis has served as President and General Manager of the
Company since January 1993, and as Executive Vice President of the Company from
August 1991 to December 1992. He was a director from December 1993 to November
1994.  He previously served as Project Manager for Canadian International Power
Services, Inc. from 1987 to 1991 in Georgetown, Guyana and in Managua,
Nicaragua.  Mr. Dupuis received his Masters of Business Administration degree
from the University of Western Ontario and his Bachelor of Electrical
Engineering degree from the University of New Brunswick in Canada.

Roland C. Gibson.  Mr. Gibson has served as Vice President-Finance of the
Company since 1991 and as Assistant Finance Manager of the Company from 1988 to
1990.  Prior to joining the Company in 1988, Mr. Gibson worked as an audit
manager for Deloitte, Haskins & Sells in Buenos Aires, Argentina.  Mr. Gibson is
a Certified Public Accountant with a degree from Universidad Nacional de La
Plata, Argentina.

                                       3
<PAGE>
 
Mats Fagerlund.  Mr. Fagerlund has been General Counsel and Senior Vice
President of Vattenfall AB since 1992 and has been a member of the board of
Nordic Power Invest AB since 1993.  Prior to that, Mr. Fagerlund served as Head
of Legal Services at Telefonaktiebolaget LM Ericsson.  Mr. Fagerlund also serves
as Director of various companies within the Vattenfall group of companies.

Leonard Bluhm.  Mr. Bluhm has been Executive Vice President and Chief Financial
Officer of NRG since January 1997.  From May 1996 to December 1996, he served as
the first President and Chief Executive Officer of NRG Generating (U.S.), Inc.
("NRGG," now CogenAmerica).  Mr. Bluhm was Vice President of NRG from January
1993 and Vice President and Chief Financial Officer from May 1993 until assuming
his position with NRGG in May 1996.  Mr. Bluhm was Chief Financial Officer of
Cypress Energy Partners, an affiliate of NRG from April 1992 to January 1993,
prior to which he was Director, International Operations and Manager,
Acquisitions and Special Projects of NRG from 1991.  Mr. Bluhm previously served
for over 20 years in various financial positions with NSP.

Ronald J. Will.  Mr. Will has been Senior Vice President, NRG, as well as
President and Chief Executive Officer, NRG Europe, since June 1989, prior to
which he served as Vice President, Operations and Engineering, of NRG since May
1992 and before that Vice President Operations from February 1991.  Prior to
that, he served as President and Chief Executive Officer of NRG Thermal, a
wholly-owned subsidiary of NRG, that provided a limited number of customers with
thermal services, from September 1989 to February 1991.  Mr. Will served in a
variety of positions with Norenco, a wholly-owned thermal services subsidiary of
NSP, including Vice President and General Manager, from October 1982 to
September 1989.

Mauricio Gonzalez.  Mr. Gonzalez was the National Secretary of Energy of Bolivia
from April 1995 to October 1996.  Mr. Gonzalez served as Chairman of the Board
and Executive President of Yacimientos Petroliferos Fiscales Bolivianos
("YPFB"), Bolivia's integrated oil and natural gas company, from September 1993
until March 1995.  Prior to joining YPFB, Mr. Gonzalez served from 1989 through
1993 as the President of Pan Andean Resources (Bolivia), a London Stock Exchange
quoted oil and gas exploration company.  Mr. Gonzalez has dual Bolivian and
American citizenship.

Gunnar Vallin.  Mr. Vallin has been Senior Vice President of Vattenfall AB since
1994 and is the Chief Executive Officer and President of Nordic Power Invest AB
("NPI") and is the Chairman of the Board of Directors of SwedPower AB.  He also
serves as a Director of Vattenfall Generating Seruices AB and of Vattenfall
Vattenkrage AB.  From 1991 to 1994, Mr. Vallin served as Division Manager at ABB
High Voltage Transmission AB.

Hans Lundgren.  Mr. Lundgren has been Vice President of Vattenfall International
AB since 1995.  He has also been Vice President for NPI Latin America since
1996.  Furthermore, Mr. Lundgren serves as a Director of Vattenfall Generator
Services AB.  From 1993 to 1995, Mr. Lundgren served as Director for Strategy
and Business Development at the corporate level of Vattenfall AB.  Prior to
joining Vattenfall, Mr. Lundgren served as an Undersecretary for Planning in the
Ministry of Industry and Commerce with responsibility for the privatization of
Swedish government owned companies.

Edwin G. Corr.  Mr. Corr has been the Director of the Energy Institute of the
Americas and Associate Director of the International Programs Center at the
University of Oklahoma since 1995.  He was a professor of Political Science and
Holder of the Henry Bellmont Chair in Public Service at the University of
Oklahoma from 1990 through 1996.  Mr. Corr served as a Foreign Service Officer
of the United States Department of State from September 1961 to September 1990.
During that period Mr. Corr held a variety of high-level positions, including,
but not limited to, serving as a Deputy Assistant Secretary of State, the U.S.
Ambassador to Peru, the U.S. Ambassador to Bolivia and the U.S. Ambassador to El
Salvador.

                                       4
<PAGE>
 
Section 16(a)  Beneficial Ownership Reporting Compliance

  Section 16(a) of the Securities Exchange Act of 1934 requires Directors,
executive officers and 10% shareholders of the Company to file reports of
changes in beneficial ownership with the Company, the Securities and Exchange
Commission and any exchange upon which the Company's common stock is traded.
Based solely on representations from the Company's Directors and executive
officers and a review of the copies of beneficial ownership reports furnished to
the Company, the Company believes that all of the Directors, executive officers
and 10% shareholders of the Company complied with such reporting requirements
during the last fiscal year.

Item 11.  Executive Compensation.

Compensation Summary

  The following table sets forth information concerning the cash and non-cash
compensation (stated in U.S. dollars), paid or to be paid by the Company to its
Chief Executive Officer and to each of its executive officers whose total salary
and bonus exceeded $100,000, for the three fiscal years ended December 31, 1998.


                              SUMMARY COMPENSATION TABLE

<TABLE> 
<CAPTION> 
                             Annual Compensation                                         Long-Term
                                                                                       Compensation 
                                                                                          Awards
-------------------------------------------------------------------------------      -----------------     ----------------
               (a)                  (b)       (c)          (d)         (e)                  (g)                   (i)

                                                                       Other
                                                                       Annual            Securities
                                                                    Compensation         Underlying            All Other
   Name and Principal Position                                         ($)(3)             Options            Compensation
                                   Year   Salary ($)    Bonus ($)                        SARS ($)(4)           ($)(5)(6)
<S>                                <C>    <C>           <C>         <C>                <C>                  <C> 
David Peterson, (1)                1998           ---          ---         ---                    ---                  ---
  Chief Executive Officer          1997           ---          ---         ---                    ---                  ---

Robert McClenachan, (2)            1998           ---          ---         ---                    ---                  ---
  Chief Executive Officer          1997           ---          ---         ---                 70,000                  ---

Roger J. Dupuis,                   1998       170,170          ---      34,000                    ---               11,100
  President and General Manager    1997       162,000       78,000      42,600                  5,000               10,600
                                   1996       154,350       78,000      44,600                  5,000                9,900

Roland C. Gibson,                  1998        98,165          ---      16,000                    ---                5,100
  Vice President Finance           1997        92,600       45,000      19,300                  2,500                4,900
                                   1996        88,200       37,500      20,500                  2,500                4,800

</TABLE> 

---------------------------
(1) Mr. Peterson served as Chief Executive Officer of the Company through
    November 1997 and was elected again to that office on August 7, 1998.

(2) Mr. McClenachan became the Chief Executive Officer of the Company in
    November 1997 and resigned on August 7, 1998.

(3) Column (e) of the above table includes the value of certain benefits (valued
    on the basis of the aggregate incremental value to the Company) provided by
    the Company to its executive officers, including a housing allowance, moving
    expenses, free electricity, personal use of a Company car, social club dues,
    personal use of Company staff, schooling for minor children, life and health
    insurance policies and transportation costs for an annual trip to the
    officer's native country.  None of the benefits 

                                       5
<PAGE>
 
    included in column (e) exceeded 25% of the total benefits for any of the
    named executive officers except: (i) Mr. Dupuis' housing allowance, which
    was $18,000 for each of the three years in 1998, 1997 and 1996 respectively;
    and (ii) Mr. Dupuis' travel allowance to his native country, which was
    $13,000, $16,000 and $16,000 in 1998, 1997 and 1996, respectively.

(4) Column (g) includes options granted to Messrs. McClenachan, Dupuis and
    Gibson under the Company's 1994 Stock Option Plan.

(5) Column (i) includes payments of $6,807, $6,483 and $6,174 to Mr. Dupuis for
    1998, 1997 and 1996, respectively, in lieu of payments for his account to a
    retirement plan.  The Company's Pension Plan was frozen as of November 1,
    1991, and terminated as of September 1, 1992, and the Company has made
    payments to Mr. Dupuis equal to 4% of his annual base salary.  Column (i)
    also includes payments to Mr. Dupuis of term life insurance premiums of
    $4,293, $4,048 and $3,730 in 1998, 1997 and 1996, respectively.

(6) Column (i) includes payments of $3,927, $3,704 and $3,528 to Mr. Gibson for
    1998, 1997 and 1996, respectively, in lieu of payments for his account to a
    retirement plan.  Column (i) also includes payments to Mr. Gibson of term
    life insurance premiums of $1,200 per year for each of the three years 1998,
    1997 and 1996.

                                       6
<PAGE>
 
                              OPTION GRANT TABLE


  The Company did not grant any stock options during the year ended December 31,
1998.

                              STOCK OPTION TABLE
                Aggregated Option Exercises in Last Fiscal Year
                       and Fiscal Year-End Option Values

<TABLE>
<CAPTION>
                                            Number of Securities        Value of Unexercised
                                           Underlying Unexercised      in-the-Money Option at
                                            Options at FY-End(#)              FY-End(#) 
 
                     Shares       Value
Name              Acquired on   Realized                                                            
                  Exercise (#)     ($)     Exercisable   Unexercisable  Exercisable   Unexercisable 
---------------------------------------------------------------------------------------------------
<S>               <C>           <C>        <C>           <C>            <C>           <C> 
David H. Peterson     ---          ---               0               0            0               0 
Robert McClenachan    ---          ---               0               0            0               0
Roger J. Dupuis       ---          ---               0           5,000            0               0
Roland C. Gibson      ---          ---               0           2,500            0               0
</TABLE>

Compensation of Directors

  Messrs. Corr and Gonzalez received $14,000 per year and $1,000 per Board
meeting, and $500 per committee meeting, attended, plus expenses.  The Chairman
of a committee received $750 for each meeting attended of that committee.  Mr.
Gonzalez and Mr. Corr also received $500 per undertaking, plus expenses, for
special assignments undertaken at the request of the Board.

Employment Agreements


  Roger J. Dupuis.  The Company and Roger J. Dupuis entered into an Employment
  ---------------                                                             
Agreement as of October 7, 1996 (the "Dupuis Employment Agreement").  The
following is a summary of the material terms of the Dupuis Employment Agreement.
Mr. Dupuis' employment by the Company shall be for an indefinite period
commencing on October 7, 1996 and ending on the date of termination pursuant to
the provisions set forth in Section 3 of the Dupuis Employment Agreement.  The
Company may terminate the Dupuis Employment Agreement at any time after October
31, 1998 by giving Mr. Dupuis sixty days' prior written notice.  Mr. Dupuis may
terminate the Dupuis Employment Agreement at any time after October 31, 1998 or
at any time upon sixty days' prior written notice upon the occurrence of certain
events, such as a change in his duties or a reduction in his salary or benefits.
The Company will pay Mr. Dupuis a base salary at the rate of $154,350 per annum,
payable in substantial equal monthly installments.  (Such amount, as it may be
increased from time to time, is hereinafter referred to as the "Base Salary").
The Base Salary and Mr. Dupuis' other compensation shall be reviewed annually
and may be increased or maintained as the Board of Directors may determine.  The
Company may also pay Mr. Dupuis an annual incentive bonus in such amount as the
Board of Directors may determine.


  Roland C. Gibson.  The Company and Roland C. Gibson entered into an Employment
  ----------------                                                              
Agreement as of October 7, 1996 (the "Gibson Employment Agreement").  Mr.
Gibson's employment by the Company shall be for an indefinite period commencing
on October 7, 1996 and ending on the date of termination pursuant to the
provisions set forth in Section 3 of the Gibson Employment Agreement.  The
Company may terminate the Gibson Employment Agreement at any time after October
31, 1998 by giving Mr. Gibson sixty days' prior written notice.  Mr. Gibson may
terminate the Gibson Employment Agreement at any time after October 31, 1998 or
at any time upon sixty days prior 

                                       7
<PAGE>
 
written notice upon the occurrence of certain events, such as a change in his
duties or a reduction in his salary or benefits. The Company shall pay Mr.
Gibson a base salary at the rate of $88,200 per annum, payable in substantial
equal monthly installments. (Such amount, as it may be increased from time to
time, is hereinafter referred to as the "Base Salary"). The Base Salary and Mr.
Gibson's other compensation shall be reviewed by the Board of Directors at least
annually and may be increased or maintained as the Board of Directors may
determine. The Company may also pay Mr. Gibson an annual incentive bonus in such
amount as the Board of Directors may determine.


Compensation Committee Interlocks and Insider Participation

  The Board of Directors' Compensation Committee was comprised during 1998 of
Edwin G. Corr, David H. Peterson and Gunnar Vallin.  Mr. Peterson is Chairman of
the Board of NRG and served as Chief Executive Officer of the Company from
December 1996 to November 1997 and since August 7, 1998 and Mr. Vallin is the
Chief Executive Officer and President of NPI.  NRG and NPI jointly own Tosli.

Item 12.  Security Ownership of Certain Beneficial Owners and Management

  The following table sets forth certain information with respect to the
beneficial ownership of shares by (i) each person who, to the knowledge of the
Company, is the beneficial owner of more than 5% of the outstanding common
stock, (ii) Directors, (iii) executive officers, and (iv) Directors and
executive officers as a group.  The persons listed in the table have sole voting
and investment power with respect to the shares shown in the table.

                                        Amount and
                                        Nature of
                                        Beneficial
Name and Address                        Ownership               Percent of Class
----------------                        ---------               ----------------

Tosli Investments B.V.                  4,060,732                     96.6%
Roger J. Dupuis.......................      0                           0
Roland C. Gibson......................      0                           0
Mats Fagerlund........................      1                           *
Mauricio Gonzalez.....................      1                           *
Robert McClenachan....................      0                           *
Leonard Bluhm.........................      1                           *
David H. Peterson.....................      1                           *
Hans Lundgren.........................      1                           *
Gunnar Vallin.........................      1                           *
Ronald J. Will........................      1                           *
Edwin G. Corr.........................      1                           *
All Directors and executive                                              
  officers as a group (12 persons)          8                           *

________________

*  Less than one percent.

                                       8
<PAGE>
 
Item 13.  Certain Relationships and Related Transactions

  Stockholders Agreement.  Pursuant to a Stockholders Agreement, dated as of
  ----------------------                                                    
December 13, 1996, NRG and NPI have made various agreements relating to their
ownership of interests in Tosli and the Company.

  Under the Stockholders Agreement, NRG and NPI agreed that they would observe
the following basic principles governing the ownership and management of the
Company and Tosli:

     (i)    NRG and NPI shall cooperate in a spirit of good faith and fair
            dealing in an effort to develop a harmonious working relationship
            for the purpose of maximizing the long-term value of their
            investments in the Company.

     (ii)   The Company shall be operated as an independent, self-sufficient
            entity.  Neither NRG nor NPI shall have authority to bind or make
            commitments on behalf of the Company or Tosli.

     (iii)  Neither NRG nor NPI shall be obligated to make any equity
            investments in or loans to the Company or Tosli or issue guarantees
            in favor of the Company or Tosli.

     (iv)   The Board of Directors of the Company shall make decisions on the
            basis of the benefit to the Company of such decisions rather than
            the partisan interest of either NRG or NPI; provided, however, that
            while Tosli holds any shares of the Company's Common Stock, Tosli
            has agreed to take all lawful action so that NRG and NPI may vote
            (subject to the corporate governance provisions of the Stockholders
            Agreement) those shares in the same proportions as their respective
            percentage ownership interests in Tosli.

     (v)    The Company shall deal at arm's-length with NRG and NPI.

     (vi)   NRG and NPI shall cooperate fully to the end that the Company and
            Tosli will qualify for a "participation exemption" under the laws of
            the Netherlands.

     (vii)  The Company shall conduct its business with due consideration to
            applicable environmental standards.


     Upon purchase of shares pursuant to the Tender Offer, Tosli became entitled
to designate all of the members of Company's Board of Directors.  Under the
Stockholders Agreement, NRG and NPI have agreed that the Board of Directors of
the Company will consist of three designees of NRG (currently Messrs. Peterson,
Bluhm and Will), three designees of NPI (currently Messrs. Fagerlund, Lundgren
and Vallin) and three additional Directors (currently Messrs. Corr, Gonzalez and
one vacancy) who are mutually satisfactory to NPI and NRG.

     The Stockholders Agreement also provides that "Major Matters" would require
the approval of at least six Directors.  Major Matters include (i) amendments to
the Company's Memorandum or Articles of Association, (ii) approvals of mergers
and other corporate reorganizations of the Company, (iii) changes in the
Company's dividend policy, (iv) any borrowings or guarantees by the Company in
excess of $10,000,000 in any one case, (v) changes in the Company's auditors,
(vi) changes in the Company's business objectives by entering into businesses
other than the generation, transmission and/or distribution of heat or
electricity, or services related thereto, (vii) any material amendments of the
Company's material agreements, (viii) any material commitments regarding the
Mato Grosso Project or the Miguillas Project, or (ix) any exit from the
Company's existing rate base.  In addition to the Board approvals specified
above, the matters referred to in clauses (i), (iv) and (vi) would require the

                                       9
<PAGE>
 
concurrence of at least one Director designated by NPI.

     The Board approvals specified above would be in addition to the approvals,
if any, required of shareholders under applicable law and the Articles of
Association.

     Under the Stockholders Agreement, the Chairman of the Board and the
Secretary of the Company are initially to be designees of NRG and thereafter the
Chairmanship is to be rotated every two years, and the position of Secretary is
to be rotated annually, between designees of NPI and NRG.

     Under the Stockholders Agreement, the Common Stock held by Tosli, and the
shares of Tosli itself, are subject to rights of first refusal and rights of
approval of transferees where the proposed transfer includes, directly or
indirectly, 25% or more of the then outstanding shares of the Company's Common
Stock or would reduce the combined holdings of NRG and NPI to less than 51% of
the then outstanding shares of the Company's Common Stock.  Neither NPI nor NRG
is to acquire any shares of the Company from the Company or other shareholders
except through Tosli.

     Pursuant to the Stockholders Agreement, in the event of the transfer of
effective working control of NPI by Vattenfall, or of NRG by Northern States
(other than a spin-off or split-off of NRG to all shareholders of Northern
States or a change of control of Northern States or Vattenfall), then the other
party would have a right to purchase the first party's interest in the Common
Stock held by Tosli and in Tosli at fair market value.

     The Stockholders Agreement states that each party would be free to pursue
other business opportunities without offering them to the Company, except as
otherwise required by applicable law.  However, each party has agreed to ensure
that none of its unilateral actions would be detrimental to the Company.

                                       10
<PAGE>
 
CAF Agreement

     The Company entered into a loan agreement with Corporacion Andina de
Fomento (the "CAF Agreement") in August 1997.  CAF is a multilateral,
supernational financial institution, the shareholders of which are the member
countries of the Andean Community (i.e., Bolivia, Colombia, Ecuador, Peru and
Venezuela), plus Chile, Mexico, Trinidad and Tobago, Brazil, Paraguay, Jamaica
and 22 private commercial banks.  The CAF Agreement provides an A Loan of up to
$30,000,000 (the "A Loan") to be provided by CAF and a B Loan of up to
$45,000,000 (the "B Loan") to be provided by ING Baring (U.S.) Capital
Corporation (or an affiliate) and other Participants.  The Company has borrowed
$75,000,000 under the CAF Agreement.

     The Loans under the CAF Agreement will be amortized in 18 semi-annual
installments of varying amounts beginning January 31, 1999 and ending July 31,
2007.

     The A Loan may be voluntarily prepaid upon 90 days notice in whole or in
part in an amount of not less than $5,000,000 beginning on July 31, 1999 subject
to the payment of (i) a prepayment fee of 2.00% if a prepayment occurs on or
before July 31, 2003, or 1.00% if a prepayment occurs thereafter and (ii)
applicable breakage costs.  The B Loan may be voluntarily prepaid in whole or in
part at any time upon 90 days notice, subject to payment of applicable breakage
costs.  Any voluntary prepayment will be made pro rata between the A Loan and
the B Loan, except that CAF may elect to waive pro rata voluntary prepayment and
allow voluntary prepayment of B Loan amounts only.  Voluntary prepayments shall
be applied pro rata to remaining principal payments due on the Loan or Loans
being prepaid.

     Certain mandatory prepayments will be required in the event of asset sales
by the Company in excess of a cumulative total of $15,000,000.

     Interest is payable semi-annually in arrears at a rate equal to 6-month
LIBOR plus a margin of 4.5% on the A Loan and 6-month LIBOR plus a margin of
4.0% in the B Loan.  Overdue amounts will bear interest at a rate of 4.00% over
the amount otherwise payable.

     The A Loan and the B Loan are collateralized by a mortgage on substantially
all of the Company's assets.

     The CAF Agreement provides for a number of Events of Default, including,
among other things, defaults in payment, or defaults in the performance of
various covenants, under the CAF Agreement, abandonment of, or cessation of work
for more than 90 days on, the Zongo Valley Expansion Project or the occurrence
of a material adverse change affecting the Company's ability to perform its
obligations under the CAF Agreement.

                                       11
<PAGE>
 
Shareholder Maintenance Agreement

     In connection with the execution of the CAF Agreement, NRG, NPI and CAF
entered into the Shareholder Maintenance Agreement.  For a period of five years,
NPI and NRG agreed to maintain a combined ownership of at least 40% of each of
the voting power and the aggregate capital stock of the Company, provided,
however, that they agreed to maintain a combined ownership of more than 50% of
each of the voting power and aggregate capital stock unless the voting stock of
the Company is publicly traded and at least 20% of the voting power is held by
persons other than NRG, NPI and their affiliates.  Thereafter, for the remaining
term of the financing, NPI and NRG agreed to maintain a combined ownership of at
least 30% of each of the voting power and aggregate capital stock of the
Company; provided, however, that they agreed to maintain a combined ownership of
more than 50% of each of the voting power and aggregate capital stock unless the
voting stock of the Company is publicly traded and at least 20% of the voting
power is held by management control of the Company, and to appoint competent
directors of the Company who will exercise diligence and attention to the
management of, and appointment of officers with appropriate competence and
experience to manage, the Company.

     Under the Shareholder Maintenance Agreement, NRG and NPI are prohibited
from encumbering or otherwise hypothecating shares in the Company or any
intermediate company through which they hold their ownership interests in the
Company.  Additional covenants include notification/information requirements,
maintenance of corporate existence, compliance with laws and regulations, and an
agreement not to modify their organizational documents.  In an event of default,
remedies include specific performance and injunctive relief as well as monetary
damages.

     The Shareholder Maintenance Agreement will automatically terminate upon the
repayment in full of all amounts payable under the CAF Agreement.  In addition,
NRG and NPI shall have the right to transfer all of their capital stock of the
Company or of Tosli pursuant to a claims payment settlement under an insurance
agreement covering expropriation risk, and thereupon the Shareholder Maintenance
Agreement shall automatically terminate.

CDLLC Agreement

     During 1998, NRG and NPI created a separate jointly-owned entity to
provide, among other things, development services on behalf of the Company.  On
October 9, 1998, this new entity, Cobee Development LLC ("CDLLC"), entered into
an agreement with the Company pursuant to which CDLLC agreed to provide
development services to the Company in connection with the Miguillas and Puerto
Suarez projects.  Under the agreement, in return for the provision of such
services by CDLLC, the Company agreed that, in the event there is a financing
closing in connection with either of the projects, it would reimburse CDLLC's
development expenses and pay CDLLC a development fee out of the financing
proceeds associated with the project.  The agreement expires on December 31,
1999 unless the parties terminate it prior to, or extend it beyond, that date.

                                       12
<PAGE>
 
                                   SIGNATURES

     Pursuant to the requirements of Section 13 or 15(d) of the Securities
Exchange Act of 1934, the Registrant has duly caused this report to be signed on
its behalf by the undersigned, thereunto duly authorized.

 COMPANIA BOLIVIANA DE ENERGIA ELECTRICA S.A. -- BOLIVIAN POWER COMPANY LIMITED


Date:  April 30, 1999               By:     /s/ Roger J. Dupuis
                                            -------------------
                                            Roger J. Dupuis
                                            President and General Manager

     Pursuant to the requirements of the Securities Exchange Act of 1934, this
report has been signed below by the following persons on behalf of the
Registrant and in the capacities and on the dates indicated.

SIGNATURE                    TITLE                            DATE
------------------------------------------------------------------------

By  /s/ David H. Peterson    Chairman of the Board            April 30, 1999
    ---------------------    and Director and Chief                  
    David H. Peterson        Executive Officer             
                             (Principal Executive Officer) 

By  /s/ Roger J. Dupuis      President and General            April 30, 1999  
    ------------------       Manager                                 
    Roger J. Dupuis                  


By  /s/ Roland C. Gibson     Vice President-Finance           April 30, 1999
    --------------------     (Principal Financial and                
    Roland C. Gibson         Accounting Officer)       
                                                       

By  /s/ Leonard Bluhm        Director                         April 30, 1999 
    -----------------                                              
    Leonard Bluhm


By  /s/ Edwin G. Corr        Director                         April 30, 1999
    ----------------                                                
    Edwin G. Corr


By  /s/ Mats Fagerlund       Director                         April 30, 1999
    ------------------                                               
    Mats Fagerlund


By  /s/ Mauricio Gonzales    Director                         April 30, 1999
    ---------------------                                            
    Mauricio Gonzales

                                       13
<PAGE>
 
By  /s/ Hans Lundgren        Director                         April 30, 1999
    -----------------                                                
    Hans Lundgren


By  /s/ Gunnar Vallin        Director                         April 30, 1999
    -----------------                                                
    Gunnar Vallin


By  /s/ Ronald J. Will       Director                         April 30, 1999
    ------------------                                               
    Ronald J. Will

                                       14