What Makes Solar Powered Robots Viable In South Africa?

At the peak of the rolling blackouts in South Africa, one of the indirect consequences was an enormous snarl up in traffic flow as robots (traffic lights) went down. This significantly increased energy consumption and wasted productive time.

Yes we do call traffic lights robots in South Africa, presumably because its “A machine or device that operates automatically or by remote control”. The Department of Transport’s magazine was titled Robot until 1998 but they now seem to use Traffic Light in formal documentation.

The Central Energy Fund (CEF) of South Africa has announced a drive to install solar-powered traffic lights at critical intersections in South Africa’s major cities. The CEF foresaw an investment of R 100 million and installations at 400 intersections. This was justified by “Quantified in monetary terms, productivity losses, accidents at uncontrolled intersections, and exhaust emissions from stationary motor vehicles all have an adverse effect on the economy,”

• » See also: Bioengineers Speed Up Evolution to Make Better Bacteria
• » Get EcoWorldly by RSS or sign up by email.

Traffic studies show that at normal traffic speed reductions in the average trip speed increases the petrol consumption significantly - for example reducing average trip speed from 30 km/h to 10 km/h almost doubles the average petrol consumption.

In a back-of-the-envelope calculation, if we assume 15% of all travel is for commuting, that 5 percent of this is effected by rolling blackouts and that average speed of the congested traffic is a high 10 km/h, the cost of the extra fuel used is R 1.3 billion a year and the additional carbon dioxide generated is 400 000 tons.

Similar calculations looking at the cost of lost time give even higher figures but are not always accepted as its the worker who suffers from a longer commute time and not the employer. However, some employers in Johannesburg have been keen to sponsor solar powered traffic lights near their offices to ease the flow of traffic to get their employees to work on time.

What is the Bigger Picture?

Eskom (the national, government-owned electricity generator) has experienced a drop in electricity demand recently as a result of the worldwide economic situation. This has caused concern that renewable energy technology will receive less investment and that the drop in price of fossil fuels will effect their viability.

However, cable theft and the effect of heavy sub tropical rainstorms are additional motivators for solar traffic lights. It is also expected that as the economy recovers rolling blackouts will once more be used to balance supply while the need to assure a successful 2010 is a strong motivator for infrastructure investment. Imagine the stadium lights going out in the final - so African!

Testing of a pilot installation by the National Energy Efficiency Agency has proven the feasibility of solar traffic lights in South Africa’s environment. The fact that most rolling blackouts take place during the day suits solar power’s output, while the installation of uninterruptible power supplies and the replacement of old lights with LEDs by a number of municipalities simplify installations.

Where Are We Today?

The current situation seems to be that not many more than 20 have been installed, that these have cost about R 300 000 each but that, for example, Johannesburg has identified 400 intersections requiring lights for which the are seeking public/private investment.

It is hoped that this initiative is continued so that we are not once again announcing and planning a solution when we are already in the middle of the problem.

Photo Credit: V 2 on Flickr under a Some Creative Commons License.

Tweet This Post