AMENDING AGREEMENT This Amending Agreement is made as of the 26111 day of June 2018. BETWEEN: TRANSCANADA PIPELINES LIMITED a CanRdian corpomtion ("'l'a·masCnnada'') "and" PORTLAND NATURAL GAS TRANSM1SSION SYSTEM a Maine General Pat·tnership ) WHEREAS TmnsCqnada and ·Shippet· re parties to a Precedent A t·eement dated October 31, 2017 (the "Agt·ccm:cnt"); and WHEREAS TransCanadn and Shlpp·et· wish to amend tlte Ag,·emnent by incre slng the Phase Ill qmmtity by 10,551 GJ/d fl'Om 182,751 GJ/d to193,302 GJ/d; NOW THEREFORE Tl'ruisCanada and Shi!>j)Cl' agree as follows: ARTICLE1 INCORI,ORA'l'ION, DEFINITIONS AND EFFECTIVE DATE 1.1 This Amencliitg Agt·ectnent aild the provisions hereof are supplemelital to the Agreement, and at'e to fol'm part of atld uwe the Sl\tne effect as though inc<;li'POI'ated in the Agreement,· 1.2Unless otherwise defind \1 this nending Agreement, all capitalized temw contained in this Amending Agt'eement which are. defined in tl\e Agreement shall fo.r all. pilrposes hereof huve the meau..ing given t<? them in the Agreement unless the context otherwise specifies Ol' requires. l ,3This Amending Agreement is effective as of the date fit·st wl'ittell above, ARTICLE2 AMENDMENTS TO THE AGREEMENT 2,1The Agreement is amended as follows: (a)by deleting the thit·d recital in itentirety and replacing it with the foll9wing:

1; - - WHEREAS pm·suant to n new capacity open season which closed on September 212017 (the "New Capacity Opcu Scnson"), Shipper requested 'frausCauadn to tnmsport up to 184,862 GJ/d of natural gas ti:om the Union Dawn rcqeipt point and 8,440 GJ/d ofnaltll'UI gas fmn1 the Unioil Parkway Bell receipl point (collectively, the "Receipt Point") to, in both cases, the East He1·efonl delivery point (inlp the PNGTS system) (the "Delivery Point,) for delivel'Y for the account of Shlt>Jl.er l!l t!u·ee phases (such three phases are sometimes referred lo individually as a "PlHlHC11 and collectively defined as the "Phases"), w.ith each Phase hav.ing its own pecifled itt" set·vice date (for each Phase, its "Iu-Scl'Vice Date")l as ;f\ll'thel' desol'llled below: •the fu·st Phqse shall have at\ In"Sel'vice Date of Novembet· l, 2018 or asoon as possible thereafter to tmnsport 39,663 GJ/day from the U.Qiou Dawn ReceJpt Point and 2,651 GJ/day ft·om the Up.lon Pm·kway Belt Receipt Poh1t fm· an aggregate-of 42,314 GJ/day, fm·a term of 22 ye n('·'Phase I"); •the second Ph se shall have an JnwService D te ofNovclnpcr 1, 2019 or as soons possible thet·eafter to transpot't 159,960 GJ/day from the Urtion bnwn Receipt Point and 7,481 GJ/day ;.,· ; fi·om the Union Pal'lcway Belt Receipt Point for nn aggregate of 167,441 GJ/day, for a term of 21 yeai's ("l,ltasc II"); and·· •the. thlrd phase shall have an lnwSet·vice Date of'NpVember 1, 2020 or as .soon as posslble therelifter to tnmsport 184,862 GJ/dfty from the U on Dawn R ceipt Point and 8,44GJ/dny f ·om the Union Parkway Belt Receipt Point for an aggregate of 193,302 GJ/day, fot a term of 20 years ("J>Jtnse U{l').·· All of the above collectively defined as the "Requested Service". ARTICL-m3 MISCELLANEOUS 3,1This Amending Agt•eemcnt supercedes "ll negotiations, discllssions and tmdertakings . ' 3.2 The Agr ement shall remain in full force and effect as mneoded by tlus Amending Agt'eetnent aud fs hereby ratified a!ld conf!qued as ameuded, of [Exect(f/on page follows]

 IN WITNESS WHEREOF the pnrties to this Amending Agreement have caused it to be executed by their d 1ly auU10rlzed officerss of the day and ycm·first written nbove. l,OnTLAND NATlJRAL GAS l'RANSMJSSION SYSTEM, BY ITS OPERATOR, l,NGTS OPERATING CO.,LLC By: TRANSCANADA PIPELINES LIMITED By:----=::;z;z ---rJS"ay: Name:1..to,._ Title:,.(-.,,,jt! .se...". '..". "'Title: DonBeU· Director.CouunarlaJ&s& Manager, Customer Service Content Review LegalR(lvlew