Hidroeletrica de Cahora Bassa (HCB), the company that operates the Cahora Bassa dam on the Zambezi river, has announced that it will spend 480 million meticais (about 14 million US dollars) on protecting HCB transmission lines against the effects of flooding.
An HCB press release said this protection will involve strengthening the pylons on or near river banks. Broader and deeper foundations for the pylons will be built, which will be able to withstand the force of the waters during peak moments of a flood.
On 12 January a massive flood on the Licungo river, in the central province of Zambezia, swept away ten pylons on the transmission lines carrying Cahora Bassa power to the north of the country. This deprived the northern provinces of Nampula, Niassa and Cabo Delgado, and the northern districts of Zambezia, of electricity for four weeks. HCB seems determined to ensure that this shall not happen again.
The first of these strengthened pylons will be installed on the line carrying electricity from Cahora Bassa to South Africa.
Pylons where the lines cross the Save, Limpopo and Nuanetsi rivers are being replaced, and the route of the line will also be altered. HCB guarantees that there will be no interruption in the supply of electricity while this work is being done.
The new towers, the release adds, are designed in such a way that the solid detritus carried by flood waters will not accumulate at the base of pylons, putting pressure on them.
Severe flooding in the Limpopo valley in 2000 interrupted the flow of HCB power to South Africa for five months. There was a partial interruption in 2013, which reduced the flow of electricity to South Africa to 65 per cent of the normal supply.
HCB power is carried to South Africa along two high voltage direct current lines each running for about 1,400 kilometres and with a total of 2,000 pylons. Some of this power is then re-exported from South Africa, along a line rented from the South African power utility Eskom, to supply Maputo and the rest of southern Mozambique.
In addition, HCB has two high voltage alternating current lines that take electricity to the centre and north of the country, and a third which carries power to Zimbabwe.
The HCB release promises that further investments will be made to ensure high levels of reliability in power supply.