Contract ID.: FT17593 Amendment No: 3 FORM OF TRANSPORTATION SERVICE AGREEMENT This Transportation Service Agreement (Agreement) is entered into by Great Lakes Gas Transmission Limited Partnership (Transporter) and ANR Pipeline Company (Shipper)....

Exhibit 99.6

Contract ID.: FT17593 Amendment No: 3 FORM OF TRANSPORTATION SERVICE AGREEMENT This Transportation Service Agreement (Agreement) is entered into by Great Lakes Gas Transmission Limited Partnership (Transporter) and ANR Pipeline Company (Shipper). WHEREAS, Shipper has requested Transporter to transport Gas on its behalf and Transporter represents that it is willing to transport Gas under the terms and conditions of this Agreement. NOW, THEREFORE, Transporter and Shipper agree that the terms below constitute the transportation service to be provided and the rights and obligations of Shipper and Transporter. 1. EFFECTIVE DATE: November 01,2020 2. CONTRACT IDENTIFICATION: FT17593 3. RATE SCHEDULE: FT 4. SHIPPER TYPE: Other 5. STATE/PROVINCE OF INCORPORATION: Delaware 6. TERM: November 01,2012 to October 31,2021 Right of First Refusal: Regulatory (in accordance with Section 6.16 of the General Terms and Conditions of Transporter's FERC Gas Tariff) 7. EFFECT ON PREVIOUS CONTRACTS: This Agreement supersedes, cancels and terminates, as of the effective date stated above, the following contract(s): Service Agreement dated November 01, 2019 with Contract Identification FT17593. 8. MAXIMUM DAILY QUANTITY (Dth/Day): Please see Appendix A for further detail. 9. RATES: Unless Shipper and Transporter have agreed to a rate other than the maximum rate, rates shall be Transporter's maximum rates and charges plus all applicable surcharges in effect from time to time under the applicable Rate Schedule (as stated above) on file with the Commission unless otherwise agreed to by the parties in writing. Provisions governing a Rate other than the maximum shall be set fotih in this Paragraph 9.

Contract ID.: FT17593 Amendment No: 3 10. POINTS OF RECEIPT AND DELIVERY: The primary receipt and delivery points are set forth on Appendix A. 11. RELEASED CAPACITY: N/A 12. INCORPORATION OF TARIFF INTO AGREEMENT: This Agreement shall incorporate and in all respects be subject to the "General Terms and Conditions" and the applicable Rate Schedule (as stated above) set forth in Transporter's FERC Gas Tariff, Third Revised Volume No. 1, as may be revised from time to time. Transporter may file and seek Commission approval under Section 4 of the Natural Gas Act (NGA) at any time and from time to time to change any rates, charges or provisions set forth in the applicable Rate Schedule (as stated above) and the "General Terms and Conditions" in Transporter's FERC Gas Tariff, Third Revised Volume No. 1, and Transporter shall have the right to place such changes in effect in accordance with the NGA, and this Agreement shall be deemed to include such changes and any such changes which become effective by operation of law and Commission Order, without prejudice to Shipper's right to protest the same. 13. MISCELLANEOUS: No waiver by either party to this Agreement of any one or more defaults by the other in the performance of this Agreement shall operate or be construed as a waiver of any continuing or future default(s), whether of a like or a different character. Any controversy between the parties arising under this Agreement and not resolved by the parties shall be detetmined in accordance with the laws of the State of Michigan. 14. OTHER PROVISIONS (As necessary): It is agreed that no personal liability whatsoever shall attach to, be imposed on or otherwise be incurred by any Partner, agent, management official or employee of the Transporter or any director, officer or employee of any of the foregoing, for any obligation of the Transporter arising under this Agreement or for any claim based on such obligation and that the sole recourse of Shipper under this Agreement is limited to assets of the Transporter. Upon termination of this Agreement, Shipper's and Transporter's obligations to each other arising under this Agreement, prior to the date of termination, remain in effect and are not being terminated by any provision of this Agreement.

Contract ID.: FT17593 Amendment No: 3 15. NOTICES AND COMMUNICATIONS: All notices and communications with respect to this Agreement shall be in writing by mail, e-mail, or other means as agreed to by the parties, and sent to the addresses stated below or to any other such address(es) as may be designated in writing by mail, e-mail, or other means similarly agreed to: ADMINISTRATIVE MATTERS: Great Lakes Gas Transmission Limited Partnership Commercial Operations 000 Xxxxxxxxx Xxxxxx, Xxxxx 000 Xxxxxxx, XX 00000-0000 ANR Pipeline Company 000 Xxxxxxxxx Xx., Xxxxx 000 Xxxxxxx, XX 00000-0000 Attn: Xxxxx Xxxxxxx AGREED TO BY: GREAT LAKES GAS TRANSMISSION LIMITED PARTNERSHIP By: Great Lakes Gas Transmission Company By: Xxx Xxxxxxxx By: Xxx Xxxx Title: Director, Transportation Accounting and Contracts Title: Director, Short Team Marketing

APPENDIX A CONTRACT IDENTIFICATION: FT17593 Date: November 01,2020 Supersedes Appendix Dated: November 01,2019 Shipper: ANR Pipeline Company Maximum Daily Quantity (Dth/Day) per Location: Point(s) of Primary Receipt Point(s) of Primary Delivery Begin Date End Date MDO MUTTONVILLE RECEIPT FORTUNE LAKE 11/1/2012 3/31/2013 506,500 SOUTH XXXXXXX DELIVERY MUTTONVILLE RECEIPT 4/1/2013 10/31/2013 390,000 MUTTONVILLE RECEIPT FORTUNE LAKE 11/1/2013 3/31/2014 506,500 SOUTH XXXXXXX DELIVERY MUTTONVILLE RECEIPT 4/1/2014 10/31/2014 207,000 MUTTONVILLE RECEIPT FORTUNE LAKE 11/112014 3/31/2015 506,500 SOUTH XXXXXXX DELIVERY MUTTONVILLE RECEIPT 4/112015 10/31/2015 207,000 MUTTONVILLE RECEIPT FORTUNE LAKE 11/1/2015 3/31/2016 506,500 SOUTH XXXXXXX DELIVERY MUTTONVILLE RECEIPT 4/1/2016 10/31/2016 207,000 MUTTONVILLE RECEIPT FORTUNE LAKE 11/1/2016 3/31/2017 506,500

SOUTH XXXXXXX DELIVERY MUTTONVILLE RECEIPT 4/1/2017 10/31/2017 207,000 MUTTONVILLE RECEIPT FORTUNE LAKE 11/1/2017 3/31/2018 506,500 SOUTH XXXXXXX DELIVERY MUTTONVILLE RECEIPT . 4/1/2018 10/31/2018 207,000 MUTTONVILLE RECEIPT FORTUNE LAKE 11/1/2018 3/31/2019 506,500 SOUTH XXXXXXX DELIVERY MUTTONVILLE RECEIPT 4/1/2019 10/31/2019 207,000 MUTTONVILLE RECEIPT FORTUNE LAKE 11/1/2019 3/31/2020 506,500 SOUTH XXXXXXX DELIVERY MUTTONVILLE RECEIPT 4/1/2020 10/31/2020 207,000 MUTTONVILLE RECEIPT FORTUNE LAKE 11/1/2020 3/31/2021 506,500 SOUTH XXXXXXX DELIVERY MUTTON VILLE RECEIPT 4/1/2021 10/31/2021 207,000 XXXXXXX RECEIPT 11/1/2012 3/31/2013 506,500 XXXXXX RECEIPT 11/1/2012 3/31/2013 506,500 SOUTH XXXXXXX RECEIPT 11/1/2012 3/31/2013 100,000 XXXXXXX RECEIPT 4/1/2013 10/31/2013 390,000 XXXXXX RECEIPT 4/1/2013 10/31/2013 207,000 XXXXXXX RECEIPT 11/1/2013 3/31/2014 506,500

XXXXXX RECEIPT 11/1/2013 3/31/2014 506,500 SOUTH XXXXXXX RECEIPT 11/1/2013 3/31/2014 100,000 XXXXXXX RECEIPT 4/1/2014 10/31/2014 207,000 SOUTH XXXXXXX RECEIPT 4/1/2014 10/31/2014 100,000 XXXXXX RECEIPT 4/1/2014 10/31/2014 207,000 XXXXXXX RECEIPT 11/1/2014 3/31/2015 506,500 XXXXXX RECEIPT 11/1/2014 3/31/2015 506,500 SOUTH XXXXXXX RECEIPT 11/1/2014 3/31/2015 100,000 XXXXXXX RECEIPT 4/1/2015 10/31/2015 207,000 XXXXXX RECEIPT 4/1/2015 10/31/2015 207,000 SOUTH XXXXXXX RECEIPT 11/1/2015 3/31/2016 100,000 XXXXXX RECEIPT 11/1/2015 3131/2016 506,500 XXXXXXX RECEIPT 11/1/2015 3/31/2016 506,500 XXXXXXX RECEIPT 4/1/2016 10/31/2016 207,000 XXXXXX RECEIPT 4/1/2016 10/31/2016 207,000

SOUTH XXXXXXX RECEIPT 11/1/2016 3/31/2017 100,000 XXXXXX RECEIPT 11/1/2016 3/31/2017 506,500 XXXXXXX RECEIPT 11/1/2016 3/31/2017 506,500 XXXXXXX RECEIPT 4/1/2017 10/31/2017 207,000 XXXXXXX RECEIPT 11/1/2017 3/31/2018 506,500 XXXXXX· RECEIPT 11/1/2017 3/31/2018 506,500 SOUTH XXXXXXX RECEIPT 11/1/2017 3/31/2018 100,000 XXXXXXX RECEIPT 10/31/2018 4/1/2018 207,000 XXXXXX RECEIPT 11/1/2018 3/31/2019 506,500 XXXXXXX RECEIPT 11/1/2018 3/31/2019 506,500 SOUTH XXXXXXX RECEIPT 11/1/2018 3/31/2019 100,000 XXXXXXX RECEIPT 4/1/2019 10/31/2019 207,000 XXXXXX RECEIPT 11/1/2019 3/31/2020 506,500 XXXXXXX RECEIPT 11/1/2019 3/31/2020 506,500 SOUTH XXXXXXX RECEIPT 11/1/2019 3/31/2020 100,000

XXXXXXX RECEIPT 4/1/2020 10/31/2020 207,000 XXXXXX RECEIPT 11/1/2020 3/31/2021 506,500 XXXXXXX RECEIPT 11/1/2020 3/31/2021 506,500 SOUTH XXXXXXX RECEIPT 11/1/2020 3/31/2021 100,000 XXXXXXX RECEIPT 4/1/2021 10/31/2021 207,000 XXXXXXX DELIVERY 11/1/2012 3/31/2013 506,500 XXXXXX DELIVERY 11/2012 3/31/2013 506,500 MUTTONVILLE DELIVERY 11/1/2012 3/31/2013 100,000 11/1/2012 3/31/2013 OTISVILLE 100,000 XXXXXX DELIVERY 4/1/2013 10/31/2013 390,000 XXXXXXX DELIVERY 11/1/2013 3/31/2014 506,500 XXXXXX DELIVERY 11/1/2013 3/31/2014 506,500 MUTTONVILLE DELIVERY 11/1/2013 3/31/2014 100,000 11/1/2013 3/31/2014 OTISVILLE 100,000 XXXXXX DELIVERY 4/1/2014 10/31/2014 207,000 XXXXXXX DELIVERY 4/1/2014 10/31/2014 207,000 XXXXXXX DELIVERY 11/1/2014 3/31/2015 506,500

MUTTONVILLE DELIVERY 11/1/2014 3/31/20I5 100,000 11/1/2014 3/31/2015 OTISVILLE 100,000 XXXXXX DELIVERY 11/1/2014 3/31/20I5 506,500 XXXXXX DELIVERY 4/1/2015 10/31/2015 207,000 XXXXXX DELIVERY 11/1/2015 3/31/2016 506,500 XXXXXXX DELIVERY 11/1/2015 3/31/2016 506,500 11/1/2015 3/31/2016 OTISVILLE 100,000 MUTTONVILLE DELIVERY 11/1/2015 3/31/2016 100,000 XXXXXX DELIVERY 4/1/2016 10/31/2016 207,000 XXXXXX DELIVERY 11/1/2016 3/31/2017 506,500 11/1/2016 3/31/2017 OTISVILLE 100,000 MUTTONVILLE DELIVERY 11/1/2016 3/31/2017 100,000 XXXXXXX DELIVERY 11/1/2016 3/31/2017 506,500 XXXXXX DELIVERY 10/31/2017 4/1/2017 207,000 XXXXXXX DELIVERY 11/1/2017 3/31/2018 506,500 XXXXXX DELIVERY 11/1/2017 3/31/2018 506,500 MUTTONVILLE DELIVERY 11/1/2017 3/31/2018 100,000

11/1/2017 3/31/2018 OTISVILLE 100,000 SOUTH XXXXXXX DELIVERY 11/1/2017 3/31/2018 100,000 XXXXXX DELIVERY 4/1/2018 10/31/2018 207,000 XXXXXX DELIVERY 11/1/2018 3/31/2019 506,500 XXXXXXX DELIVERY 11/1/2018 3/31/2019 506,500 11/1/2018 3/31/2019 OTISVILLE 100,000 MUTTONVILLE DELIVERY 11/1/2018 3/31/2019 100,000 SOUTH XXXXXXX DELIVERY 11/1/2018 3/31/2019 100,000 XXXXXX DELIVERY 4/1/2019 10/31/2019 207,000 XXXXXX DELIVERY 11/1/2019 3/31/2020 506,500 XXXXXXX DELIVERY 11/1/2019 3/31/2020 506,500 11/1/2019 3/31/2020 OTISVILLE 100,000 MUTTON VILLE DELIVERY 11/1/2019 3/31/2020 100,000 SOUTH XXXXXXX DELIVERY 11/1/2019 3/31/2020 100,000 XXXXXX DELIVERY 4/1/2020 10/31/2020 207,000 XXXXXX DELIVERY 11/1/2020 3/31/2021 506,500

XXXXXXX DELIVERY 11/1/2020 3/31/2021 506,500 11/1/2020 3/31/2021 OTISVILLE 100,000 MUTTONVILLE DELIVERY 11/1/2020 3/31/2021 100,000 SOUTH XXXXXXX DELIVERY 11/1/2020 3/31/2021 100,000 XXXXXX DELIVERY 4/1/2021 10/31/2021 207,000