The ominous sound of the drill starts up and you brace yourself, your fingernails making grooves in the chair arm.
Then... Suddenly... Silence... And blackness.
Yip, Eskom has chosen that precise moment to shed its load.
One dental practice in Cape Town has eliminated this potential horror story by installing a solar energy system which will eventually take them completely off the grid.
Patheodent Dental Health Care has installed two Victron Energy Blue Motion inverters with a capacity of 10,000VA each, 20 Solar World panels adorn the north-facing side of the roof to collect the sunlight, and there are 16 batteries packed in the basement to store the energy.
"As we only installed the system this winter, we'll still have to see what the full capacity is, but at the moment - on a good sunny day - the solar panels produce about 4000W of energy. The batteries store enough energy to run our entire practice for about four hours. We expect this to almost double in summer when we will be able to run pretty much off the grid," says Dr Andrew Ellis, one of the partners at Patheodent.
The entire system is automated so when there is loadshedding, there is a seamless changeover without any outage at all.
With an extremely busy practice run by four dentists, Patheodent also has some cutting-edge dental technology that they have to keep running during business hours, so they believe the solar installation is a good investment.
"It has cost R310,000 so far. A generator would have cost more than this to run our entire practice and then on top of that, you must maintain it and buy diesel. Our solar system - due to a reduced reliance on Eskom - should be paid off in about six years," Dr Ellis explains.
Although they will probably install a few more panels at a later stage, Patheodent currently has enough capacity to run the entire practice during loadshedding when a combination of battery power and solar is used.
"The solar system is used all the time, but the batteries only during loadshedding, but none of the energy generated is ever wasted. The solar feeds directly into the practice circuit, and also charges the batteries. In the event of the solar power being greater than the energy we need, then it will feed back into the grid," Dr Ellis says.
As far as Dr Ellis is aware, Patheodent is the only dental practice in South Africa that has invested in an alternative energy source to keep their business up and running.
