Brazil’s Cemig pilots energy storage in combination with distributed generation


Brazilian energy company Cemig is undertaking R&D on the implementation of energy storage in the country’s distribution networks.

The project, undertaken under the regulator Aneel’s research and development programme, has implemented three battery storage systems alongside a 549kWp solar system. The location is the Uberlândia municipality in the Triângulo Mineiro area in the west of Minas Gerais state.

The three storage systems have a total capacity of 1.58MWh. One of the systems with 1.36MWh capacity is lithium-ion technology. The other two, totalling 225kWH, are lead acid batteries.

The aim is to test the performance of the lead-acid batteries in optimising the energy within the system, either supplying energy to the grid from the PV or from the storage.

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“The purpose of this configuration is to take advantage of the existing photovoltaic inverters to optimise the cost of implementing storage systems, and to avoid the need to install hybrid inverters,” explains Alécio de Melo Oliveira, an engineer and the project manager at Cemig.

He adds that the systems are being operated manually at this stage but a SCADA is under development for remote automated operation.

With the data gathered, the goal is to assess the feasibility of grid-connected energy storage as support for data centres.

Another goal is to develop a business model for PV and storage systems in the residential sector to provide support to the network.

The R$22 million (US$3.8 million) initiative was started in 2017 and is due for completion in 2021. Project partners include PV supplier Alsol Energias Renováveis, the Federal University of Paraíba and the Federal Institute of Education, Science and Technology of Rio Grande do Norte.

Distributed generation in Brazil

The Brazilian Association of Distributed Generation (Associação Brasileira de Geração Distribuída, ABGD) has reported the “historic milestone” of more than 400,000 end customers in Brazil being supplied with renewable energies from more than 305,000 distributed generation systems.

Of these about three-quarters are in the residential sector, a fifth are commercial and industrial and the remainder in rural areas.

“It is necessary to end the myth that distributed generation is for large entrepreneurs and wealthier consumers,” says ABGD president, Carlos Evangelista.

“There are projects of all sizes and with diverse sources, in addition to countless social projects taking the benefits of distributed generation to the neediest.”