Companhia de Electricidade de Macau - CEM, S.A. (CEM) is a public utility company in the Macao SAR with the sole concession to transmit, distribute and sell high, medium and low-voltage electricity, possessing power generation facilities. It is the concessionaire for the public service of management of Macao’s common services tunnel. CEM is also responsible for the operation and maintenance of Macao’s public lighting facilities, public electric vehicle charging network, and public photovoltaic facilities.

The Macao electricity transmission network is comprised of 29 high-voltage (HV) substations, 8 HV switching stations with a total length of 1,088 kilometers of HV cables ranging from voltage levels of 66kV, 110kV and 220kV. The Guangdong-Macao power network is interconnected by eight circuits of 220kV main supply lines and four circuits of 110kV backup lines, forming a transmission network with three 220kV interconnections, namely the ‘North, Central and South', for transmitting electricity to Macao. 

The 11kV medium-voltage (MV) electricity distribution network is comprised of 1,854 customer substations and 48 switching stations connected by MV cables with a total length of 2,893 kilometers. The low-voltage (LV) distribution network is made up of 1,101 kilometers of cable, while the street lighting network comprises 727 kilometers of cable and around 18,341 streetlights. Almost entire CEM’s power network in both transmission and distribution is comprised of underground cables.