Exhibit 99.1


                                                                EXECUTION COPY


                              AGREEMENT AND WAIVER
                              --------------------


AGREEMENT AND WAIVER,  dated as of March 22, 2007 by and among NATIONAL GRID USA
("National Grid"),  KEYSPAN CORPORATION  ("KeySpan"),  KEYSPAN ELECTRIC SERVICES
LLC ("KeySpan Electric"),  KEYSPAN GENERATION LLC ("Genco"),  and KEYSPAN ENERGY
TRADING  SERVICES  LLC  ("KETS")   (collectively,   the  "National  Grid/KeySpan
Companies") and the LONG ISLAND LIGHTING  COMPANY d/b/a LIPA and the LONG ISLAND
POWER AUTHORITY (the "Authority" and collectively with LIPA, "LIPA").

                              W I T N E S S E T H:
                              --------------------


     WHEREAS, on February 25, 2006 National Grid plc, National Grid US8 Inc. and
KeySpan  entered  into a  certain  Agreement  and Plan of  Merger  (the  "Merger
Agreement") pursuant to which National Grid US8 Inc., a wholly-owned  subsidiary
of  National  Grid,  will  merge  with and into  KeySpan,  with  KeySpan  as the
surviving entity and thereby becoming a wholly owned subsidiary of National Grid
(the "Merger"), subject to the terms and conditions of the Merger Agreement;

     WHEREAS,  the  consummation  of the  Merger  will  result in a  "Change  of
Control",  as such term is defined  in  Appendix  A to the  Management  Services
Agreement,  dated as of June 26, 1997, as amended,  between KeySpan Electric,  a
wholly-owned  subsidiary  of  KeySpan,  and LIPA  (the  "MSA")  of both  KeySpan
Electric and KeySpan;

     WHEREAS,  the  consummation  of the Merger  will also result in a Change of
Control of (a) KeySpan and Genco under the Power Supply  Agreement,  dated as of
June 26,  1997,  as amended,  between  Genco and LIPA (the  "PSA"),  and (b) the
Energy Management Agreement, dated as of June 26, 1997, as amended, between KETS
and LIPA (the "EMA");

     WHEREAS,  KeySpan and certain of its affiliates and LIPA have entered into:
(i) the  Settlement  Agreement  and Release,  dated  January 31, 2006;  (ii) the
Amended and Restated  Management  Services  Agreement (the "Amended MSA"), dated
January 31, 2006;  and (iii) the Option and Purchase and Sale  Agreement,  dated
January 31, 2006, as amended by letter agreement,  dated as of December 11, 2006
(the "Option Agreement")  (collectively,  the "2006  Agreements"),  all of which
will become effective upon receipt of required regulatory approvals;





     WHEREAS,  the  consummation  of the Merger  will also result in a Change of
Control of both KeySpan Electric and KeySpan under the Amended MSA;

     WHEREAS,  upon such Change of Control an Event of Default  will occur under
the MSA,  the PSA,  the EMA and the Amended MSA, as a result of which LIPA would
have the right to terminate  any of these  agreements  immediately  upon written
notice;

     WHEREAS, following extensive discussions and negotiations among the parties
hereto  following  the  announcement  of the  Merger  Agreement  and  LIPA's due
diligence  review of National Grid's  financial  condition and operations in the
United  States,  LIPA  believes  that it would be in its  best  interest  not to
terminate  the MSA,  the PSA, the EMA or the Amended MSA and to waive the Events
of Default resulting from a Change of Control occasioned by the Merger; and

     WHEREAS,  in  consideration  for  LIPA's  waiver of the  Events of  Default
resulting  from a Change of Control of the MSA, the PSA, the EMA and the Amended
MSA, the parties have agreed to enter into this  Agreement and Waiver based upon
the terms and  conditions  set forth herein,  as well as (i) an Amendment to the
Amended MSA (the "MSA Amendment"),  dated March 22, 2007; (ii) a First Amendment
to the Option Agreement (the "Option Amendment"),  dated March 22, 2007; (iii) a
Second Option and Purchase and Sale Agreement (the "Second Option"), dated March
22, 2007; (iv) a Fourth Amendment to the Power Supply Agreement, dated March 22,
2007;  (v) a Right of First  Refusal  Agreement,  dated March 22, 2007;  (vi) an
Omnibus Gas  Transportation and Balancing  Agreement,  dated March 22, 2007; and
(vii) certain other related  agreements  referred to therein  (collectively  (i)
through (vii), the "National Grid Agreements").

     NOW THEREFORE, in consideration of the premises and other good and valuable
consideration, the receipt and sufficiency of which are hereby acknowledged, the
parties hereto, intending to be legally bound, agree as follows:


SECTION 1. WAIVER OF EVENTS OF DEFAULT.
           ----------------------------

     Subject to the terms and conditions hereof and the covenants and agreements
set forth herein,  in the event the Merger is consummated  LIPA hereby waives as


                                       2



of the Effective Date the Events of Default  resulting  therefrom  under each of
Sections  7.2(A)(1)(a) of the MSA and  7.2(A)(1)(a) of the Amended MSA,  Section
12.3.1(a) of the PSA and Section 7.2.1(a) of the EMA.


SECTION 2. LIPA ALLOCATION OF MERGER SAVINGS.
           ----------------------------------

     2.1. National Grid hereby agrees to allocate to LIPA for the benefit of the
LIPA customers a portion of the synergy savings  resulting from the Merger.  The
parties  agree that  subject to increase  pursuant to Section 2.2 below,  LIPA's
equitable  share of such Merger  synergy  savings is based upon LIPA's  customer
revenues  (less its fuel and  purchased  power and  Shoreham  related  costs) as
compared to other  companies  entitled to a share of the  National  Grid/KeySpan
synergy  savings and net of National  Grid's  estimated  cost of achieving  such
synergy savings.  The "Synergy Savings Amount" is equivalent to US$69,100,000 on
a net present value basis using a discount rate of 7.8%,  based on equal sharing
between LIPA and National  Grid/KeySpan  of the expected  savings  between April
2007 and the  remaining  terms of the Amended  MSA and the PSA (which  expire on
December 31, 2013 and May 28, 2013,  respectively),  with cost to achieve  being
levelized over a 10 year period, all as set forth in Schedule A. Accordingly, on
the Effective Date (as defined in Section 14.10 below), National Grid shall make
a lump sum payment to LIPA of the Synergy  Savings  Amount or at LIPA's  option,
will pay to LIPA an amount over the remaining life of the Amended MSA and on the
dates as set forth in Schedule  B,such  payments to be made by wire  transfer in
immediately  available  United  States  Dollars  to such  account  as LIPA shall
specify in a written notice to National Grid.

     2.2. The Synergy Savings Amount shall be increased in the event that in its
order  approving  the Merger,  the New York State  Public  Service  Commission's
("NYSPSC")  determination  of the net Merger  synergy  savings,  determined in a
manner  consistent with the  calculation in Section 2.1 (or if such  calculation
can not be  reasonably  applied  based  upon the rate  plan or plans  ultimately
approved by the NYSPSC in the Merger proceeding and the NYSPSC's order approving
the Merger,  then on a fair and  equitable  basis,  taking  into  account to the
fullest extent  practicable the components and methodology of the calculation so
as to reflect the intent of the parties),  would result in an allocation thereof
to LIPA's  customers  of an amount in excess of  US$81,400,000  on a net present


                                       3



value basis using the mid-year  convention.  In such event,  the Synergy Savings
Amount  payable by  National  Grid to LIPA on the  Effective  Date (or at LIPA's
option over the term of the Amended MSA) shall be increased by the present value
(using a 7.8% discount rate) of such amount exceeding US$81,400,000.


SECTION 3. AMENDMENTS TO THE AMENDED MSA.
           ------------------------------

     3.1.  General.  LIPA and KeySpan  Electric will,  simultaneously  herewith,
enter into the MSA  Amendment  in the form  attached  as Exhibit 1 hereto  which
generally provides,  subject to the terms and conditions set forth therein,  for
the following:

     3.1.1 LIPA Approval Rights. LIPA shall have the right to approve (with such
approval not to be unreasonably withheld) proposed key employee changes.

     3.1.2 Staffing  Levels.  KeySpan  Electric will maintain  minimum  staffing
levels for its "on-Island field force". National Grid agrees to treat LIPA as if
it were a National Grid affiliate for purposes of providing  field and logistics
support  and  mutual  aid in the  event of a storm or  other  adverse  operating
conditions.

     3.1.3  Customer  Services.  KeySpan  Electric  shall  maintain  "on-Island"
customer service functions, including a call center and customer walk-in centers
pursuant  to an  overall  plan  satisfactory  to  LIPA as set  forth  in the MSA
Amendment.

     3.1.4  Performance  Metrics.  The  parties  will enter into a Clean  Energy
Initiative performance metric as set forth in the MSA Amendment.

     3.1.5 Storm  Hardening.  For  Contract  Years 2008  through  2013,  KeySpan
Electric  will  provide  LIPA an  annual  credit in the  amount of  US$1,000,000
towards LIPA's funding of incremental  expenditures  or allocated  Capital Costs
related to storm hardening for the T&D System (e.g., hazardous tree removal).

     3.1.6 Other. The definition of "Prevalent  Utility Services" in the Amended
MSA will be  revised  and  standards  and  decision  making  procedures  will be
established  to address  potential  conflicts of interest  arising from National
Grid's representation of LIPA's interests before the New York Independent System
Operator and other similar industry bodies.

     3.2. Further Consideration.  As additional  consideration for LIPA's waiver
of the Events of Default  in the event of a Change of  Control  as  provided  in
Section 1 hereof,  National Grid hereby agrees to pay to LIPA the further sum of
US$7,000,000. On the Effective Date, National Grid shall pay LIPA such amount in
immediately  available United States Dollars by wire transfer to such account as
LIPA shall designate in writing to National Grid.


                                       4



SECTION 4. NORTHPORT PLANT AND PORT JEFFERSON PLANT ENVIRONMENTAL UPGRADES.
           ----------------------------------------------------------------

     Genco  and LIPA  will,  simultaneously  herewith,  enter  into  the  Fourth
Amendment to the Power Supply Agreement in the form attached as Exhibit 2 hereto
which generally provides, subject to the terms and conditions set forth therein,
as follows:

     4.1 As promptly as  practicable  following the Effective  Date,  Genco will
design and implement a detailed work program  designed to upgrade the operations
and  environmental  control  systems at Units Nos. 3 and 4 at Genco's  Northport
generating  facility (the "Northport  Plant") in order to improve the efficiency
of, and reduce NOx emissions from, these Units (the "Northport Project").  Among
other  things,  Genco  agrees,  subject to Section 4.2 below,  to install at the
Northport  Plant  Units  Nos.  3 and  4  General  Electric  Dense  Pack  turbine
efficiency systems, or their equivalent, including last stage turbine blades and
related NOx emission control systems. An implementation schedule which estimates
project milestones for the Northport Project is set forth on Schedule C hereto.

     4.2 Conduct of the  Northport  Project  shall be subject to (a)  technical,
environmental  and  economic  feasibility,  and (b) the receipt of all  required
regulatory  approvals,  including any necessary  approvals by the New York State
Department of Environmental  Conservation and the U.S. Environmental  Protection
Agency,  the terms and conditions of which shall be reasonably  satisfactory  to
both the National Grid/KeySpan Companies and LIPA.

     4.3  Genco  and  LIPA  agree  to  fully  cooperate  on the  design,  scope,
procurement  and  installation of equipment and systems related to the Northport
Project.  Without  limitation,  LIPA shall have the right to review and  approve
(such approval not to be unreasonably withheld) all submissions to regulatory or
other governmental agencies and contracts or other commitments for equipment and
services related to the Northport Project, and to participate in any meetings or
proceedings  with  regulatory or other agencies or bodies with respect  thereto.
Genco and LIPA  shall  provide  copies to each  other of all  correspondence  in
connection  with  the  foregoing.  As  promptly  as  practicable  following  the
Effective Date, Genco and LIPA shall each designate a  representative  who shall
have principal  responsibility  for  coordinating and  communicating  activities
involving the Northport Project on behalf of that party.


                                       5



     4.4 Reserved.

     4.5 Within a reasonable  time  following  the  Effective  Date,  subject to
technical,  environmental and economic  feasibility and receipt of all necessary
regulatory  approvals,  the terms and  conditions  of which shall be  reasonably
satisfactory to both the National  Grid/KeySpan  Companies and LIPA,  Genco will
implement  and  install  at Units Nos. 1 and 2 of the  Northport  Plant  turbine
efficiency  systems and related NOx emission  control  systems similar to and on
the same terms and conditions as those for the Northport Project (excluding last
stage  turbine  blades).  To this end,  Genco agrees to commence  the  necessary
technical,  environmental and economic  feasibility studies within eighteen (18)
months following the Effective Date.

     4.6 National Grid, at its sole expense, agrees to perform a Northport Plant
engineering  and economics  repowering  study that will consider  environmental,
fuel supply and transmission issues. The scope of work and deliverables relating
to the "Northport Plant Repowering  Study" is attached hereto as Schedule D. The
parties will mutually agree in advance on the timing of such study.

     4.7 As promptly as  practicable  following the Effective  Date,  Genco will
design and  implement a work plan  designed to upgrade the NOx emission  control
systems at Units Nos. 3 and 4 at Genco's Port Jefferson  generating station (the
"Port  Jefferson  Plant") in order to reduce NOx emissions from these Units (the
"Port Jefferson NOx Reduction Project").  Such upgrades shall, as in the case of
the  Northport  Project,  be subject to  technical,  environmental  and economic
feasibility  and  receipt  of  all  required  regulatory   approvals  reasonably
satisfactory  to the parties and the other terms and conditions and  provisions,
including  with respect to Genco's cost  recovery,  as are set forth herein.  An
implementation  schedule  which  estimates  project  milestones,  for  the  Port
Jefferson NOx Reduction Project is set forth in Schedule C hereto.

     4.8 The parties  estimate  that the total  capital  cost of (a) the turbine
efficiency  systems and related NOx emission control systems for Northport Plant
Unit Nos. 3 and 4, (b) the turbine  efficiency  and NOx emission  control system
for Northport Plant Units Nos. 1 and 2, and (c) the NOx emission control systems
at  Port  Jefferson  3  and 4  will  be  approximately  US$100,000,000,  in  the
aggregate.


                                       6



     4.9. The parties agree that a special cost recovery  mechanism  shall apply
to the  capital  investments  described  in  Sections  4.1,  4.5 and 4.7  above.
Specifically,  the annual revenue  requirements  for these  facilities  shall be
based upon 100 percent debt financing at a rate equal to that obtainable by an A
rated issuer of 20-year  fixed rate tax exempt debt.  The parties  further agree
that Genco shall recover incremental revenue  requirements  associated with such
projects under the PSA's existing cost recovery  mechanism;  provided,  however,
such mechanism  shall be amended to provide that,  with respect to these assets,
recovery  of  the  cumulative  revenue  requirements  shall  be  limited  to the
cumulative fuel and emission allowance savings from such projects.


SECTION 5. RESERVED.
           ---------


SECTION 6. LIPA OPTION TO PURCHASE THE E.F. BARRETT AND FAR ROCKAWAY PLANTS.
           -----------------------------------------------------------------


     6.1. Pursuant to the Option Agreement, Genco has granted to LIPA the option
to purchase Genco's E.F. Barrett Plant and/or the Far Rockaway Plant and certain
related assets subject to the terms and conditions set forth therein. The Option
Agreement provides that unless exercised,  LIPA's option thereunder shall expire
at 3 p.m. on May 31, 2008.

     6.2. Genco and LIPA will,  simultaneously  herewith,  enter into the Option
Amendment in the form  attached as Exhibit 3 hereto which  provides,  subject to
the terms and  conditions  set forth  therein,  for a change in the  "Expiration
Date" (as such term is defined in the Option  Amendment)  to a date which is (a)
in the case of the E.F.  Barrett Plant,  May 31, 2008 and (b) in the case of the
Far Rockaway Plant, May 31, 2008.

     6.3 The  Option  Amendment  further  provides  for the  grant to LIPA of an
option to purchase  (but only if LIPA  exercises its option to purchase the E.F.
Barrett Plant), on the same terms and conditions as those applicable to the E.F.
Barrett Plant,  Genco's Internal Combustion Units on the E.F. Barrett Plant site
and related  assets,  which assets are currently  excluded from LIPA's  purchase
option.


                                       7



SECTION 7. WADING RIVER AND SHOREHAM PLANT PURCHASE OPTIONS.
           -------------------------------------------------


     As  provided by and  subject to the terms and  conditions  set forth in the
Second Option,  Genco hereby agrees to grant LIPA an option  (exercisable  for a
six month  period  following  the date on which the  Merger is  consummated)  to
purchase  Genco's  Wading River and/or  Shoreham  combustion  turbine plants and
related  assets for a  purchase  price  equal to (a) in the case of all  assets,
other than the related CWIP and  materials  and  supplies,  their net book value
plus  twenty-five  percent  (25%) and (b) in the case of such CWIP and materials
and  supplies  their net book value.  Simultaneously  herewith,  the parties are
entering  into the  Second  Option,  in the form  attached  as Exhibit 4 hereto,
providing for the foregoing.

SECTION 8. SALE OF OTHER GENCO PLANTS.
           ---------------------------


     8.1.  National Grid,  KeySpan and Genco hereby agree that in the event they
should decide to sell,  transfer  (other than to a majority owned  affiliate) or
otherwise dispose of any of the Genco  "Generating  Facilities" (as such term is
defined in the PSA), in addition to LIPA's  existing  rights under the PSA, they
shall  provide  LIPA  with  (a)  prompt  written  notice  thereof  and  (b)  the
opportunity  to  participate  in any such  proposed  sale or  other  disposition
process  (whether by way of a  competitive  bid,  privately  negotiated  sale or
otherwise)  on a basis  equivalent  to that  provided  to all other  prospective
purchasers.

     8.2.  National  Grid and Genco  hereby agree to grant LIPA a right of first
refusal  to  purchase  any (but  not  less  than  all) of the  Genco  Generating
Facilities  (as such term is defined in the PSA) which Genco proposes to sell to
a foreign or foreign controlled entity. Simultaneously herewith, the parties are
entering into a Right of First Refusal Agreement, in the form attached hereto as
Exhibit 5, providing for the foregoing.


                                       8




SECTION 9. REPLACEMENT POWER INSURANCE.
           ----------------------------

     9.1. In order to protect LIPA from the potentially higher cost of obtaining
replacement  power during summer peak periods in the event of a forced outage or
derating  of certain key Genco  plants,  National  Grid hereby  agrees to obtain
replacement power insurance coverage at a premium of up to $1 million a year for
three years following the Effective Date (subject to extension  depending on the
ability of Genco's plants to satisfy certain availability requirements).  If the
PSA  performance  metric for  availability  is not within the penalty  range for
three  (3)  consecutive  years,  then  National  Grid will be  relieved  of this
insurance procurement requirement going forward.

     9.2. National Grid shall procure such replacement power insurance to become
effective on a date provided by LIPA after the Effective  Date.  LIPA shall have
the right to review the terms and conditions of the insurance policy which shall
be reasonably satisfactory to the parties.


SECTION 10. GAS TRANSPORTATION RATE CHARGES.
            --------------------------------

     As  provided by and  subject to the terms and  conditions  set forth in the
Omnibus Gas Transportation and Balancing Agreement,  commencing on the Effective
Date, the parties agree that (a) the expiration  date for the rate and balancing
provisions with respect to the gas  transportation  services provided to certain
generating plants as set forth in the Agreement and Plan of Merger,  dated as of
June 26, 1997 by which,  among other  things,  the  Authority  acquired the Long
Island  Lighting  Company,  shall be extended  from November 27, 2009 to May 28,
2013,  (b) the  expiration  date for such  rate and  balancing  provisions  with
respect to the gas  transportation  services  provided  to  generating  stations
installed  since the date of LIPA's  acquisition  of LILCO with respect to which
LIPA has  entered  into power  purchase  agreements  (collectively,  "Fast Track
Units" or "FTUs") shall be extended from the Effective Date,  subject to certain
cash-out balancing provisions, and (c) up to 1500 MW of LIPA owned or contracted
for generation within KeySpan Gas East Corporation d/b/a KeySpan Energy Delivery
Long Island's ("KEDLI") service territory, not covered in paragraphs (a) and (b)
above,  entering  service  prior to May 28, 2013 will be subject to the rate and
cash-out balancing provisions applicable to the FTUs.  Simultaneously  herewith,
the parties are  entering  into the Omnibus  Gas  Transportation  and  Balancing
Agreement, in the form of Exhibit 6 hereto, reflecting the foregoing.


                                       9



SECTION 11. TAX CERTIORARI PROCEEDINGS.
            ---------------------------

         Notwithstanding any provisions to the contrary in the PSA or the June
26, 1997 Agreement and Plan of Merger, between the KeySpan parties and LIPA, for
the term of the PSA National Grid and Genco hereby agree that unless directed to
do so by LIPA, they shall not initiate any tax certiorari proceedings with
respect to any Genco "Generating Facilities", as such term is defined in the
PSA.


SECTION 12. ELECTRIC AND GAS EFFICIENCY PROGRAMS
            ------------------------------------

     National Grid agrees to provide  US$12,000,000  to be spread equally over a
6-year  period to fund  LIPA/National  Grid  co-branded  joint  electric and gas
efficiency  projects (the "Joint Efficiency Effort" hereinafter also referred to
as "JEE").  LIPA  intends to provide  for its  participation  in JEE through its
existing Clean Energy Initiative or other follow-on efficiency program. National
Grid currently  anticipates to provide for its participation in the JEE from its
proposed gas DSM program or through funding  available from NYSERDA in the event
a  state-wide  gas  SBC is  implemented.  The  objective  of JEE is to  identify
efficiency  opportunities  that  include both  electric  and gas savings.  It is
anticipated  that  the  initiatives   undertaken  through  JEE  will  result  in
comprehensive multiple end-use projects  characteristic of combined electric and
gas efficiency programs. Experience gained through the completion of these joint
projects  will help  identify  how the gas  efficiency  programs  that  KEDLI is
proposing  to offer can be  integrated  most  effectively  with LIPA's  existing
electric  efficiency  programs.  Both  National  Grid  and  LIPA  will  actively
participate  in the  development of the projects  undertaken  through JEE. While
overall  administration  and  implementation  of JEE is expected to be conducted
within LIPA's existing energy efficiency programs, prior to commencement of JEE,
National  Grid and LIPA will  mutually  agree on the  details of JEE,  which may
include,  but are not  limited  to: (a) classes of  ratepayers  and/or  customer
segments that the projects would target (e.g.,  commercial and low income);  (b)
number of projects per year (e.g., 4 to 5 projects per class of ratepayer);  (c)
timetable  for project  completion;  (d) annual  budget per  ratepayer  class or
customer segment; (e) project identification  procedures and project eligibility
factors to be  considered  for  selection;  (f)  allocation of costs and savings
among efficiency programs;  (g) project and expenditure reporting  requirements;
and (h)  identification  of  measures  and methods  for  calculating  efficiency
savings.


                                       10



SECTION 13. CONFLICTS WITH OTHER AGREEMENTS
            -------------------------------

     The terms and conditions of the 2006  Agreements,  the PSA, the EMA and the
National Grid Agreements shall exclusively control the rights and obligations of
the parties  thereunder  and if there is any conflict  between (a) the Agreement
and Waiver,  and (b) the terms and conditions of the 2006  Agreements,  the PSA,
the EMA or the  National  Grid  Agreements,  the  agreements  listed in (b) will
govern.


SECTION 14. GENERAL PROVISIONS.
            -------------------

     14.1. Notices.  All notices and other communications given or made pursuant
to this  Agreement  shall be in  writing  and  shall be deemed to have been duly
given  or made if (i) sent by  registered  or  certified  mail,  return  receipt
requested,  or (ii) hand delivered,  or (iii) sent by prepaid overnight carrier,
with a record of receipt,  to the parties at the following addresses (or at such
other addresses as shall be specified by the parties by like notice):


                  if to LIPA:           Long Island Power Authority
                                        333 Earle Ovington Blvd., Suite 403
                                        Uniondale, NY 11553
                                        Attn: General Counsel

                  and to:               Thelen Reid Brown Raysman & Steiner LLP
                                        875 Third Avenue
                                        New York, NY 10022
                                        Attn: Douglas E. Davidson

                  if to the National    National Grid
                  Grid/KeySpan          25 Research Drive
                  Companies:            Westborough, MA 01582
                                        Attn: Lawrence J. Reilly


                  and to:               KeySpan Corporation
                                        One MetroTech Center
                                        Brooklyn, NY 11201
                                        Attn: John J. Bishar, Jr.


     Each notice or communication shall be deemed to have been given on the date
received.

     14.2. Headings.  The headings contained in this Agreement are for reference
purposes only and shall not affect in any way the meaning or  interpretation  of
this Agreement.


                                       11



     14.3.  Miscellaneous.  This  Agreement,  together  with  the  Exhibits  and
Schedules  annexed  hereto:  (i) except as provided in Section 13 hereof,  shall
constitute  the entire  agreement and supersede all other prior  agreements  and
understandings,  both written and oral, among the parties,  or any of them, with
respect to the subject  matter  hereof and thereof;  (ii) shall be binding upon,
and inure to the benefit of, the parties hereto and thereto and their respective
successors  and permitted  assigns and are not intended to confer upon any other
person,  any  rights  or  remedies  hereunder  or  thereunder;  and (iii) may be
executed in two or more  counterparts  which together shall  constitute a single
agreement.

     14.4.  Governing Law. This Agreement shall be governed by, and construed in
accordance  with,  the laws of the State of New York  (without  giving effect to
conflict of law  principles)  as to all  matters,  including  but not limited to
matters of validity, construction, effect, performance and remedies. THE PARTIES
HERETO  AGREE THAT VENUE IN ANY AND ALL ACTIONS AND  PROCEEDINGS  RELATED TO THE
SUBJECT MATTER OF THIS AGREEMENT  SHALL BE IN THE STATE COURTS IN AND FOR NASSAU
COUNTY,  NEW YORK OR THE FEDERAL  COURTS IN AND FOR THE EASTERN  DISTRICT OF NEW
YORK, WHICH COURTS SHALL HAVE EXCLUSIVE  JURISDICTION FOR SUCH PURPOSE,  AND THE
PARTIES HERETO IRREVOCABLY  SUBMIT TO THE EXCLUSIVE  JURISDICTION OF SUCH COURTS
AND IRREVOCABLY WAIVE THE DEFENSE OR AN INCONVENIENT FORUM TO THE MAINTENANCE OF
ANY SUCH  ACTION OR  PROCEEDING.  SERVICE OF  PROCESS  MAY BE MADE IN ANY MANNER
RECOGNIZED BY SUCH COURTS.  EACH OF THE PARTIES  HERETO  IRREVOCABLY  WAIVES ITS
RIGHT TO A JURY TRIAL WITH  RESPECT  TO ANY ACTION OR CLAIM  ARISING  OUT OF ANY
DISPUTE IN  CONNECTION  WITH THIS  AGREEMENT  OR THE  TRANSACTIONS  CONTEMPLATED
HEREBY.

     14.5. Assignment.  Neither this Agreement nor any of the rights,  interests
or  obligations  hereunder  shall be assigned by the parties  hereto without the
prior  written  consent of the other  parties and any attempt by a party to make
any such  assignment  without such prior written consent shall be null and void.
No party shall be relieved of any liability  arising hereunder in respect of any
assignment pursuant to this Section, unless such assignor has received a written
release  expressly  excepting  such assignor  from any liability  that may arise
hereunder.


                                       12



     14.6.  Waiver;  Amendment.  No  waiver  by any  party  hereto  of any term,
condition or obligation of this  Agreement  shall be valid unless in writing and
signed by the waiving  party.  No failure or delay by either party hereto at any
time to require the other party hereto to perform  strictly in  accordance  with
the terms hereof shall  preclude such party from  requiring  performance by such
other  party  hereto at any later  time.  No waiver of any one or several of the
terms,  conditions  or  obligations  of this  Agreement,  and no partial  waiver
thereof, shall be construed as a waiver of any of the other terms, conditions or
obligations of this  Agreement.  This  Agreement may not be amended,  changed or
modified  in any  fashion  except by  written  instrument  signed by each of the
parties hereto.

     14.7. Further  Assurances.  The parties hereto agree to execute and deliver
such other  instruments,  agreements and other  documents and to take such other
action as may be reasonably necessary to further the purposes of the Agreement.

     14.8.  Representations and Warranties.  The National Grid/KeySpan Companies
hereby represent and warrant to LIPA, and LIPA hereby represents and warrants to
the National Grid/KeySpan Companies that:

     14.8.1  Due  Authorization  and  Binding  Obligation.  Such  party has duly
authorized the execution and delivery of this Agreement. This Agreement has been
duly  executed and  delivered  by such party.  No consent or  authorization  of,
filing  with,  notice  to, or other  act by or in  respect  of any  governmental
authority  or any other  person is required in  connection  with the  execution,
delivery, performance,  validity or enforceability of this Agreement except for,
in the case of LIPA (a)  receipt  of  approval  of the New York  State  Attorney
General  (as to  form)  and  (b)  receipt  of  approval  of the New  York  State
Comptroller (such approvals being collectively  referred to as the "Governmental
Approvals").

     14.8.2 No Conflict. Neither the execution nor the delivery by such party of
this Agreement nor the  performance by such party of its  obligations  hereunder
nor the consummation by such party of the transactions  contemplated hereby will
(a) upon receipt of the Governmental Approvals, conflict with, violate or result
in a breach of any law or  governmental  regulation  applicable to such party or
(b) conflict with, violate or result in a breach of any term or condition of any
judgment,  decree,  agreement or instrument to which such party is a party or by
which such party or any of its  properties or assets are bound,  or constitute a
default under such judgment, decree, agreement or instrument.


                                       13



     14.8.3 No Litigation.  There is no action, suit or other proceeding, at law
or in equity,  before or by any court or  governmental  authority  pending or to
such party's best knowledge,  threatened,  which relates to this  Agreement,  or
which would materially and adversely affect the performance by such party of its
obligations hereunder.

     14.8.4 No Legal  Prohibition.  Upon receipt of the Governmental  Approvals,
there  will  be no law  applicable  to  such  party  which  would  prohibit  the
performance  by  such  party  of  this  Agreement  or any  of  the  transactions
contemplated hereby.

     14.9.  Fees and Expenses.  Each party shall bear its own costs and expenses
(including those of such party's legal,  financial and other advisors)  incurred
in connection with the transactions contemplated by this Agreement.

     14.10.  Effective  Date.  This Agreement  shall become legally  binding and
effective only upon satisfaction of each of the following  conditions  precedent
(the date upon which all such  conditions  are  satisfied,  being the "Effective
Date"):

     14.10.1  Approvals  reasonably  satisfactory to National Grid and LIPA from
the New York State  Comptroller  and the New York State Attorney  General (as to
form) of this Agreement and each of the National Grid Agreements;

     14.10.2 Each of the 2006 Agreements shall have become effective pursuant to
their respective terms and be in full force and effect; and

     14.10.3 The Merger shall have been consummated.

     14.11. Termination.  This Agreement may be terminated at any time by mutual
written consent of the parties hereto.





                                       14





         IN WITNESS WHEREOF, each party hereto has duly executed this Agreement
as of the date first above written.




NATIONAL GRID USA                              LONG ISLAND POWER AUTHORITY

By:  /s/Lawrence J. Reilly                By:  /s/Kevin S. Law
     ---------------------                     ---------------
     Name:  Lawrence J. Reilly                 Name:  Kevin S. Law
     Title: Executive Vice President and       Title: Chairman
            General Counsel


KEYSPAN CORPORATION                            LONG ISLAND LIGHTING COMPANY
                                               d/b/a/ LIPA
By:  /s/John J. Bishar Jr.                By:  /s/Richard M. Kessel
     ---------------------                     --------------------
     Name:  John J. Bishar Jr                  Name:  Richard M. Kessel
     Title: Executive Vice President           Title: CEO & President



KEYSPAN ELECTRIC SERVICES LLC

By:  /s/John J. Bishar Jr.
     ---------------------
     Name: John J. Bishar Jr.
     Title: Executive Vice President



KEYSPAN GENERATION LLC

By:  /s/John J. Bishar Jr.
     ---------------------
     Name:  John J. Bishar Jr.
     Title: Executive Vice President



KEYSPAN ENERGY TRADING SERVICES LLC

By:  /s/John J. Bishar Jr.
     ---------------------
     Name:  John J. Bishar Jr.
     Title: Executive Vice President



                                       15




                                   Schedule A
                                   ----------


                                [GRAPHIC OMITTED]









                               [GRAPHIC OMITTED]






                                       16









                               [GRAPHIC OMITTED]









                               [GRAPHIC OMITTED]














                                       17









                               [GRAPHIC OMITTED]





                               [GRAPHIC OMITTED]














                                       18



                                   Schedule B
                                   ----------


                                Synergy Payments
                              (Combined MSA & PSA)
                                  Calendar Year


                                [GRAPHIC OMITTED]












                                       19





                                   Schedule C
                                   ----------

               Implementation Schedule and Project Milestones for
       the Northport Project and the Port Jefferson NOx Reduction Project







                                [GRAPHIC OMITTED]








                                       20




                                   Schedule D
                                   ----------

                        Northport Plant Repowering Study

                                  Scope of Work

A comprehensive engineering,  economic and environmental feasibility study shall
be conducted by a recognized and qualified consulting firm mutually agreeable to
National  Grid,  KeySpan and the Long Island  Power  Authority  ("LIPA") for the
repowering of the Northport  Plant. The study shall utilize and expand upon, the
existing repowering studies conducted under LIPA/KeySpan's direction by Lockwood
Green.  The study  scope  shall  contain  a 20 year  study  period  and shall be
determined  in  consultation  with LIPA.  The scope shall  include the following
aspects:

1.  Examination of the number of existing units which could be repowered and the
maximum incremental capacity which could be added to the site given the existing
physical, technical, regulatory and other constraints of the site.

2. Examination of the advantages, disadvantages, risks and EPC (Engineer Procure
and Construct)  costs of the various  repowering  options  available,  including
"Hybrid"  (re-utilization  of  existing  steam   turbines/condensers  etc.)  and
"Backyard"  (building  of  stand  alone  new  combined  cycle  capacity  and the
concurrent  retirement/mothballing  or curtailed use of the existing  facility).
Site layout drawings for each option shall be developed and provided.

3. Examination of the electric  transmission upgrades required and the estimated
EPC costs  necessary to deliver the capacity and energy into the LIPA system for
each repowering approach.

4. Examination of the fuel supply infrastructure  upgrade requirements and their
estimated costs for each repowering approach.

5.  Examination  of the cooling  system  options  available  and their EPC costs
including (i) continued use of the existing once through  cooling  system,  (ii)
use of natural draft cooling towers, (iii) mechanical draft cooling towers, (iv)
air cooled  condensers  and (v) the possible use of a Substratum  Intake  System
(SIS) once through cooling configuration.  Cooling system analysis shall include
an assessment  of the  licensability  of the existing once through  system under
existing and anticipated state and federal regulation.

6. A comparison  of before and after stack  emission  rate and total annual mass
emissions for key air pollutants  including NOx, SO2, and CO2 and  determination
of long term emission  impacts of the repowering in  conjunction  with the total
LIPA system.

7. A pre and post  repowering  air quality  impact  comparison and optimum stack
height analysis.

8. An examination of the noise impacts and the mitigation  options and EPC costs
for each repowering approach.

9. An examination of the aesthetic impacts of the various options.


                                       21



10. An  examination  of waste  water  management  options,  including  re-use of
existing waste water treatment facilities,  required modifications and estimated
EPC costs, and an examination of incremental fresh water supply requirements, if
any.

11.  An  examination  of  the  required  modifications  to  existing  substation
infrastructure and their estimated EPC cost.

12.  An  examination  of  repowering  scenarios  within an  integrated  resource
management  plan (MAPPS  analysis-  with  support from and in  conjunction  with
LIPA's  planning  organization).  Such analysis shall include an estimate of the
optimal timing for the  introduction of repowering  capacity  increments  within
LIPA's integrated resource plan and load growth estimates, an examination of the
electric  system  reliability and fuel diversity  implications  and the electric
rate impact of the various repowering options.

13. An overall  examination of the  licensability  of the various  options under
federal,  state and local law and an  estimate  of the  licensing  requirements,
approach, duration, milestones and approvals required.

14. An examination of the property tax and or pilot payment  implications of the
various repowering options.

15. An  examination  of the ammonia  delivery,  storage and safety  implications
associated with the Selective Catalytic Reduction (SCR) NOx control systems.

16. An examination of demolition requirements if any associated with the various
repowering options and their EPC costs.

17. An examination of necessary  outage durations and the LIPA system impacts of
unavailable  capacity,  if any, during  construction for the various  repowering
options.

Deliverables:
- -------------

After  consultation  with LIPA  regarding  the study of the various  options the
consultant  shall provide a  preliminary  report  identifying  the most feasible
repowering  options and an analysis of the rationale for their selection and the
rejection of the other options examined.

After  review and approval by National  Grid/KeySpan  and LIPA,  the  consultant
shall  develop and provide a conceptual  designs,  detailed  site layout  plans,
budgetary  level EPC cost  estimates,  approximate  licensing,  procurement  and
construction schedule, heat balance, water balance, environmental impact and air
quality  benefit  assessment and an electric rate impact  assessment for each of
the highest feasibility  repowering options agreed upon by National Grid/KeySpan
and LIPA.







                                       22





                                    Exhibit 1


                          Amendment to the Amended MSA













                                       23





                                    Exhibit 2


                 Fourth Amendment to the Power Supply Agreement














                                       24





                                    Exhibit 3


          First Amendment to the Option and Purchase and Sale Agreement
















                                       25





                                    Exhibit 4


                  Second Option and Purchase and Sale Agreement















                                       26





                                    Exhibit 5


                        Right of First Refusal Agreement












                                       27





                                    Exhibit 6

               Omnibus Gas Transportation and Balancing Agreement














                                       28