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4. CONCESSIONS AND AUTHORIZATIONS (Details) | 12 Months Ended
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Dec. 31, 2020
Energy purchased for resale [member] |  |
Disclosure Of Electricity Concessions And Authorizations [line items] |  |
Company holding concession or authorization | Cemig D | [1]
Concession or authorization contract | 002/1997 003/1997 004/1997 005/1997 | [1]
Expiration date | 12/2045 | [1]
National Grid [member] |  |
Disclosure Of Electricity Concessions And Authorizations [line items] |  |
Company holding concession or authorization | Cemig GT | [2]
Concession or authorization contract | 006/1997 | [2]
Expiration date | 01/2043 | [2]
Substation - SE Itajub [member] |  |
Disclosure Of Electricity Concessions And Authorizations [line items] |  |
Company holding concession or authorization | Cemig GT | [2]
Concession or authorization contract | 79/2000 | [2]
Expiration date | 10/2030 | [2]
Central Geradora Elica Volta Do Rio Wind Power Plants [member] |  |
Disclosure Of Electricity Concessions And Authorizations [line items] |  |
Company holding concession or authorization | Volta do Rio | [3]
Concession or authorization contract | Resolution 660/2001 | [3]
Expiration date | 01/2031 | [3]
Central Geradora Elica Praias De Parajuru Wind Power Plants [member] |  |
Disclosure Of Electricity Concessions And Authorizations [line items] |  |
Company holding concession or authorization | Parajuru | [3]
Concession or authorization contract | Resolution 526/2002 | [3]
Expiration date | 09/2032 | [3]
GAS DISTRIBUTION [member] |  |
Disclosure Of Electricity Concessions And Authorizations [line items] |  |
Company holding concession or authorization | Gasmig | [1]
Concession or authorization contract | State Law 11,021/1993 | [1]
Expiration date | 01/2053 | [1]
Sa Carvalho Hydroelectric Plants [member] | National Electrical Energy Agency [member] |  |
Disclosure Of Electricity Concessions And Authorizations [line items] |  |
Company holding concession or authorization | Sa Carvalho | [4]
Concession or authorization contract | 01/2004 | [4]
Expiration date | 12/2024 | [4]
Igarape Thermal Plants [member] | National Electrical Energy Agency [member] |  |
Disclosure Of Electricity Concessions And Authorizations [line items] |  |
Company holding concession or authorization | Cemig GT | [5]
Concession or authorization contract | 07/1997 | [5]
Expiration date | 08/2024 | [5]
Nova Ponte Hydroelectric Plants [member] | National Electrical Energy Agency [member] |  |
Disclosure Of Electricity Concessions And Authorizations [line items] |  |
Company holding concession or authorization | Cemig GT | [4],[6]
Concession or authorization contract | 07/1997 | [4],[6]
Expiration date | 07/2025 | [4],[6]
Queimado Consortium [member] | National Electrical Energy Agency [member] |  |
Disclosure Of Electricity Concessions And Authorizations [line items] |  |
Company holding concession or authorization | Cemig GT | [4]
Concession or authorization contract | 06/1997 | [4]
Expiration date | 01/2033 | [4]
Irape Hydroelectric Plants [member] | National Electrical Energy Agency [member] |  |
Disclosure Of Electricity Concessions And Authorizations [line items] |  |
Company holding concession or authorization | Cemig GT | [4]
Concession or authorization contract | 14/2000 | [4]
Expiration date | 02/2035 | [4]
Itutinga Hydroelectric Plants [member] | National Electrical Energy Agency [member] |  |
Disclosure Of Electricity Concessions And Authorizations [line items] |  |
Company holding concession or authorization | Cemig Geracao Itutinga | [7]
Concession or authorization contract | 10/2016 | [7]
Expiration date | 01/2046 | [7]
Salto Grande Hydroelectric Plants [member] | National Electrical Energy Agency [member] |  |
Disclosure Of Electricity Concessions And Authorizations [line items] |  |
Company holding concession or authorization | Cemig Geracao Salto Grande | [7]
Concession or authorization contract | 09/2016 | [7]
Expiration date | 01/2046 | [7]
Emborcacao Hydroelectric Plants [member] | National Electrical Energy Agency [member] |  |
Disclosure Of Electricity Concessions And Authorizations [line items] |  |
Company holding concession or authorization | Cemig GT | [4],[6],[8]
Concession or authorization contract | 07/1997 | [4],[6],[8]
Expiration date | 07/2025 | [4],[6],[8]
Camargos Hydroelectric Plants [member] | National Electrical Energy Agency [member] |  |
Disclosure Of Electricity Concessions And Authorizations [line items] |  |
Company holding concession or authorization | Cemig Geracao Camargos | [7]
Concession or authorization contract | 11/2016 | [7]
Expiration date | 01/2046 | [7]
Salto Voltao Hydroelectric Plants [member] | National Electrical Energy Agency [member] |  |
Disclosure Of Electricity Concessions And Authorizations [line items] |  |
Company holding concession or authorization | Horizontes Energia | [4]
Concession or authorization contract | Resolution 331/2002 | [4]
Expiration date | 10/2030 | [4]
Cajuru Gafan Hoto and Martins Hydroelectric Plants [member] | National Electrical Energy Agency [member] |  |
Disclosure Of Electricity Concessions And Authorizations [line items] |  |
Company holding concession or authorization | Cemig Geracao Oeste | [7]
Concession or authorization contract | 16/2016 | [7]
Expiration date | 01/2046 | [7]
Dona Rita Ervalia Neblina Peti Sinceridade And Tronqueiras Hydroelectric Plants [member] | National Electrical Energy Agency [member] |  |
Disclosure Of Electricity Concessions And Authorizations [line items] |  |
Company holding concession or authorization | Cemig Geracao Leste | [7]
Concession or authorization contract | 14/2016 and 15/2016 | [7]
Expiration date | 01/2046 | [7]
Coronel Domiciano Joasal Marmelos Paciencia E Piau Hydroelectric Plants [member] | National Electrical Energy Agency [member] |  |
Disclosure Of Electricity Concessions And Authorizations [line items] |  |
Company holding concession or authorization | Cemig Geracao Sul | [7]
Concession or authorization contract | 12/2016 and 13/2016 | [7]
Expiration date | 01/2046 | [7]
Sao Bernardo Hydroelectric Plants [member] | National Electrical Energy Agency [member] |  |
Disclosure Of Electricity Concessions And Authorizations [line items] |  |
Company holding concession or authorization | Cemig GT | [4]
Concession or authorization contract | 02/2013 | [4]
Expiration date | 08/2025 | [4]
Poco Fundo Hydroelectric Plants [member] | National Electrical Energy Agency [member] |  |
Disclosure Of Electricity Concessions And Authorizations [line items] |  |
Company holding concession or authorization | Geracao Poço Fundo | [4]
Concession or authorization contract | 01/2021 | [4]
Expiration date | 05/2045 | [4]
Rio De Pedras Hydroelectric Plants [member] | National Electrical Energy Agency [member] |  |
Disclosure Of Electricity Concessions And Authorizations [line items] |  |
Company holding concession or authorization | Cemig GT | [4]
Concession or authorization contract | 02/2013 | [4]
Expiration date | 09/2024 | [4]
Salto Do Passo Velho Hydroelectric Plants [member] | National Electrical Energy Agency [member] |  |
Disclosure Of Electricity Concessions And Authorizations [line items] |  |
Company holding concession or authorization | Horizontes Energia | [4]
Concession or authorization contract | Resolution 331/2002 | [4]
Expiration date | 10/2030 | [4]
PCH Pai Joaquim Hydro Electric Plants [member] | National Electrical Energy Agency [member] |  |
Disclosure Of Electricity Concessions And Authorizations [line items] |  |
Company holding concession or authorization | Cemig PCH | [4]
Concession or authorization contract | Authorizing Resolution 377/2005 | [4]
Expiration date | 04/2032 | [4]
Salto Paraopeba Hydroelectric Plants [member] | National Electrical Energy Agency [member] |  |
Disclosure Of Electricity Concessions And Authorizations [line items] |  |
Company holding concession or authorization | Horizontes Energia | [4]
Concession or authorization contract | Resolution 331/2002 | [4]
Expiration date | 10/2030 | [4]
Machado Mineiro Hydroelectric Plants [member] | National Electrical Energy Agency [member] |  |
Disclosure Of Electricity Concessions And Authorizations [line items] |  |
Company holding concession or authorization | Horizontes Energia | [4]
Concession or authorization contract | Resolution 331/2002 | [4]
Expiration date | 07/2025 | [4]
Rosal Hydroelectric Plants [member] | National Electrical Energy Agency [member] |  |
Disclosure Of Electricity Concessions And Authorizations [line items] |  |
Company holding concession or authorization | Rosal Energia | [4]
Concession or authorization contract | 01/1997 | [4]
Expiration date | 05/2032 | [4]
Santa Luzia Hydroelectric Plants [member] | National Electrical Energy Agency [member] |  |
Disclosure Of Electricity Concessions And Authorizations [line items] |  |
Company holding concession or authorization | Cemig GT | [4]
Concession or authorization contract | 07/1997 | [4]
Expiration date | 02/2026 | [4]
Tres Marias Hydroelectric Plants [member] | National Electrical Energy Agency [member] |  |
Disclosure Of Electricity Concessions And Authorizations [line items] |  |
Company holding concession or authorization | Cemig Geracao Tres Marias | [7]
Concession or authorization contract | 08/2016 | [7]
Expiration date | 01/2046 | [7]
Furnas - Pimenta - Transmission line [member] | National Electrical Energy Agency [member] |  |
Disclosure Of Electricity Concessions And Authorizations [line items] |  |
Company holding concession or authorization | Centroeste | [2]
Concession or authorization contract | 004/2005 | [2]
Expiration date | 03/2035 | [2]
[1] | Concession contracts that are within the scope of IFRIC 12 and under which the concession infrastructure assets are recorded under the intangible and financial assets bifurcation model, and in compliance with IFRS 15, the infrastructure under construction has been classified as a contract asset.
[2] | These refer to transmission concession contracts, for which a contract asset was recognized upon the application of IFRS 15, for being subject to satisfaction of performance obligations.
[3] | This refers to concessions, given by the process of authorization, for generation, as an independent power producer, of wind power, sold under the Proinfa program. The assets tied to the right of commercial operation are recorded in PP&E. The rights of authorization of commercial operation that are classified as an Intangible.
[4] | Generation concession contracts that are not within the scope of IFRIC 12, whose infrastructure assets are recorded as PP&E since the concession grantor does not have control over whom the service is provided to as the output is being sold mainly in the Free Market ('ACL').
[5] | On December 6, 2019, Aneel suspended Igarape Plant commercial operation upon Cemig GT's claim for early termination of its concession contract, and, as a result, the corresponding assets were written-off from Cemig GT's financial statement position. In February 2021, the Thermal Plant Igarape concession was extinct. by the Brazilian Mining and Energy Ministry, in consideration of the termination request submitted by Cemig GT. Concession contracts that are within the scope of IFRIC 12 and under which the concession infrastructure assets are recorded under the intangible and financial assets bifurcation model, and in compliance with IFRS 15, the infrastructure under construction has been classified as a contract asset. Aneel approved, through Authorizing Resolution n. 9.735, on Februarty 23, 2021, the transfer of the concession contract from Cemig GT to Cemig Poco Fundo. This transfer was formally agreed on April 16, 2021, resulting in a new contract (01/2021), which also extended the concession to 05/2045.
[6] | On July 17, 2020, Cemig GT filed a statement of its interest in extending these plants concession, under the independent producer regime, outside the regime of quotas, to ensure its right of option under the legislative changes currently under discussion, relating to the group of measures to modernize the electricity sector. Any actual decision will only be made after publication by the Brazilian Mining and Energy Ministry and by the regulator, Aneel, of the conditions for extension, which will be submitted to decision by Cemig's governance bodies at the due time.
[7] | Generation concession contracts within the scope of IFRIC 12, under which Cemig has the right to receive cash and therefore, recognizes a concession financial assets.
[8] | Bank Deposit Certificates (CDBs), accrued interest at 50% to 108%, of the CDI Rate (Interbank deposit rates) published by the Custody and Settlement Chamber (Cetip) in 2020 (80% to 106% in 2019 and 40% to 106% in 2018). For these CDBs, the Company has repo transactions which state, on their trading notes, the bank's commitment to repurchase the security, on demand, on the maturity date of the transaction, or earlier.

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