Electric Company Nantucket Electric Company each d/b/a National Grid D.P.U. 18-150 Attachment AG-1-98 Page 1 of 2

NATIONAL GRID PLC

NATIONAL GRID (US) HOLDINGS LTD

- NATGRIDTW1 LTD NATIONAL GRID (US) INVESTMENTS 4 LTD - NATIONAL GRID TWENTY-FIVE LTD

NATIONAL GRID TWELVE LTD NATIONAL GRID (US) PARTNER 1 LTD

NATIONAL GRID (US) INVESTMENTS 2 LTD NATIONAL GRID NORTH AMERICA INC.

NATGRID ONE LTD NATIONAL GRID US LLC NATIONAL GRID USA 3 NATIONAL GRID TEN NATIONAL GRID NATIONAL GRID NGT TWO LTD INSURANCE USA LTD TWENTY THREE LTD NATIONAL GRID US 6 LLC

GRIDAMERICA HOLDINGS INC.

50% NEW ENGLAND POWER - EUA ENERGY INVESTMENT CORP. WAYFINDER GROUP INC. NIAGARA MOHAWK COMPANY - MASSACHUSETTS ELECTRIC COMPANY SWAN LAKE NORTH HOLDINGS INC. 90% - METROWEST REALTY LLC 17% HOLDINGS LLC - NANTUCKET ELECTRIC COMPANY VERMONT GREEN - NATIONAL GRID TRANSMISSION GREENERU, INC. 100% NATIONAL GRID CONNECT INC. LINE DEVCO, LLC 32% - CONNECTICUT YANKEE SERVICES CORPORATION ATOMIC POWER COMPANY SWAN LAKE - NATIONAL GRID USA SERVICE CLEAN LINE ENERGY 18.42% (19.5%) NORTH COMPANY INC See separate PARTNERS LLC - MAINE YANKEE ATOMIC NATIONAL GRID GREEN HYDRO, LLC - NEES ENERGY INC. chart ENBALA HOLDINGS INC. POWER COMPANY (24%) HOMES INC. - NEW ENGLAND ELECTRIC on page 2 CABRILLO - YANKEE ATOMIC TRANSMISSION CORPORATION ENERGY ELECTRIC COMPANY (34.5%) - NEW ENGLAND ENERGY 50% STORAGE LLC - NEW ENGLAND HYDRO- NIAGARA MOHAWK OPINAC NORTH INCORPORATED SUNRUN NEPTUNE POWER CORPORATION AMERICA INC. TRANSMISSION CORP. - NEWPORT AMERICA CORPORATION (3.27%) INVESTOR 2016, LLC. - THE NARRAGANSETT ELECTRIC 16% - NEW ENGLAND HYDRO- COMPANY 50.434% TRANSMISSION ELECTRIC - VALLEY APPLIANCE AND 50% NM PROPERTIES INC. E VIONYX ,INC. COMPANY INC. (3.27%) MERCHANDISING COMPANY NEW ENGLAND HYDRO- TRANSMISSION CORPORATION NIAGARA MOHAWK - LANDWEST, INC. LAND MANAGEMENT & ENERGY INC. 50.434% - UPPER HUDSON DEVELOPMENT, INC. 26% NEW ENGLAND HYDRO- 50% DEVELOPMENT INC. TRANSMISSION ELECTRIC COMPANY INC. DIRECT GLOBAL PORT OF THE ISLANDS POWER, INC. NORTH, LLC NEW ENGLAND HYDRO FINANCE COMPANY INC. Massachusetts Electric Company Nantucket Electric Company each d/b/a National Grid D.P.U. 18-150 Attachment AG-1-98 Page 2 of 2

NATIONAL GRID USA

5%

NATIONAL GRID - KEYSPAN GAS EAST CORPORATION UNIT 40 SUBLESSOR, KEYSPAN ENERGY NGNE LLC 99% GENERATION LLC - NATIONAL GRID ELECTRIC SERVICES LLC LLC CORPORATION - NATIONAL GRID ENERGY TRADING SERVICES LLC - NATIONAL GRID ENGINEERING & SURVEYING INC. 1% GRID NY LLC NATIONAL GRID NE HOLDINGS 2 LLC 28.3% - BOSTON GAS COMPANY TRANSCO LLC - COLONIAL GAS COMPANY - TRANSGAS INC. - MYSTIC STEAMSHIP CORPORATION - PHILADEPLPHIA COKE CO., INC NATIONAL GRID NATIONAL GRID NATIONAL GRID PORT - KHB VENTURE , LLC (33.33%) GENERATION GLENWOOD ENERGY JEFFERSON ENERGY VENTURES LLC CENTER, LLC CENTER LLC

- ISLAND PARK LI ENERGY STORAGE ENERGY CENTER, SYSTEM, LLC (50%) LLC (50%) THE NATIONAL GRID KEYSPAN MHK, INC. NATIONAL GRID SERVICES INC. NATIONAL GRID -LI SOLAR UNION GAS COMPANY DEVELOPMENT TECHNOLOGIES INC. GENERATION, LLC 50% 50% HOLDINGS CORP. 18.2% (50%) 9.7% EAST MONTAUK - CLEAN ENERGY MYHOMEKEY.COM ENERGY IMPACT FUND LP HAMPTON ENERGY GENERATION, LLC ENERGY STORAGE (50%) STORAGE CENTER, CENTER, LLC LLC 8 KSI CONTRACTING KSI ELECTRICAL, KSI MECHANICAL, NATIONAL GRID LLC LLC LLC ENERGY SERVICES LLC 9.68% 5.29% NORTH EAST NYSEARCH NYSEARCH TRANSMISSION CO., INC. RMLD, LLC ROBOTICS, LLC KEYSPAN ENERGY NATIONAL GRID ENERGY KEYSPAN PLUMBING SERVICES INC. MANAGEMENT LLC SOLUTIONS, INC.

METRO ENERGY L.L.C

NATIONAL GRID BROKEN NATIONAL GRID KEYSPAN NATIONAL KEYSPAN NATIONAL GRID NATIONAL GRID NATIONAL GRID NATIONAL GRID ALGONQUIN LLC BRIDGE NORTH EAST INTERNATIONAL GRID IGTS 77% MIDSTREAM INC. MILLENIUM LLC ISLANDER EAST LNG GP LLC LNG LP LLC CORP. VENTURES INC. CORPORATION CORP. 23% PIPELINE LCC 20% 0.5% 99.5% 26.25% 50% ALGONQUIN GAS KEYSPAN CI TRANSMISSION, MIDSTREAM LLC LIMITED MILLENIUM ISLANDER EAST NATIONAL GRID LNG LLC PIPELINE PIPELINE COMPANY, LLC COMPANY, LLC

KEYSPAN ENERGY DEVELOPMENT Co.