The national roads agency is going solar.

Toll plazas managed by SANRAL and its concessionaires have, in the past, received their power from the national electricity grid. This power is used for the daily activities of the toll plazas – which operate on a 24/7 basis – as well as supporting infrastructure such as warehouses, training centres or workshops.

SANRAL made a decision to depart from a “business as usual” approach with the introduction of a solar plant at the Dalpark Plaza on the N17. This was a bold move as energy, and renewable energy, in particular, is outside SANRAL’s core business activities and primary areas of expertise.

The agency introduced the use of renewable energy sources in managing road infrastructure and activities as far back as 2008 with the use of Variable Message Signs (VMS) during the construction of the Gauteng Freeway Improvement Project. This was later extended to fixed points along some of the major corridors in Cape Town and Durban.

Subsequently, SANRAL introduced solar-powered toll plazas at two of its plazas. The Dalpark Plaza – a SANRAL-run plaza – uses a solar plant for its mainline toll plaza operations and the Diamond Hill Plaza (managed by TRAC) started using solar power as an alternative energy source in September 2014.

Solar panels on the top of the plaza collect sun power which is then converted into electricity to run the operational requirements of the plaza. At Dalpark, all the operations, as well as an adjacent workshop, are run using solar power during daytime. It generates 65 kilowatts of power into the grid (on average).

Diamond Hill generates up to 40 kilowatts of power for the grid and, depending on the weather conditions, has resulted in savings on energy of more than 50%. As such, solar power is used to run all operations.

The two plants serve as pilot projects and the objective is to roll out further solar powered toll plazas along the 3 120 kilometres of freeway that constitute SANRAL’s toll road portfolio.

In addition, energy-efficient lighting has been fitted to reduce consumption. This means that by replacing conventional luminaires with LED technology, the agency is able to save 30% of its power requirement. Had this not been done, far more solar panels would have had to be fitted at a much greater expense.

Meanwhile, as road construction and maintenance activities have an inevitable impact on the environment, SANRAL’s approach is to mitigate the impact of these activities with interventions such as the use of Reclaimed Asphalt (RA).

For example, in the rehabilitation of the N2 between Murchison and Marburg, the use of RA was specified at 40%, resulting in 40% less aggregate to be crushed, thus less basic rock excavated from quarries, and in turn less diesel was used in loading, transporting, and crushing of rock for aggregate, bitumen imports.

This translates to significant cost saving and also eliminates the need for disposal of used road building material, which means no requirement for landfilling which also comes at the usual costs of transport and space.

SANRAL has a dedicated environmental unit which oversees environmental impact assessment programmes prior to construction programmes and monitors the subsequent management of the construction process and gives input to maintenance programmes.

SANRAL’s approach is to go beyond compliance with the applicable national and provincial legislation. It is committed to an approach of ‘continual improvement’ that is demonstrated by the increasing use of renewable energy in road infrastructure management and reflected in its general environmental practices and support for research activities at tertiary institutions.

An example of this proactive approach is its early decision to completely eliminate tar products used for road construction and to switch to asphalt which is bitumen-based and more environmentally friendly

Construction projects on major roads such as the N2 in the Eastern Cape were accompanied by projects to relocate protected plants in collaboration with botany experts from the academic and research communities. Where required, road plans are changed to protect and conserve sensitive ecological areas.

SANRAL continues to conduct research into areas such as noise reduction caused by traffic on road surfaces and follows global trends in the sustainable management of road infrastructure.