Loeriesfontein Wind Farm has announced that its wind turbine foundations are utilising one of the world’s lowest quantities of Portland cement in the concrete formulation.

The foundations are designed using an 89% replacement of cement, resulting in, what is believed to be, one of the world’s lowest carbon footprints for any wind farm foundation; according to research scientist, and head of Murray & Roberts’ Concrete Centre for Excellence, Cyril Attwell.

The first two bases, which were completed on 13 October, utilised an 80% replacement of Portland cement, whilst the remaining foundations use a unique design comprising 35kgs of high grade Portland cement per cubic meter, an 89% reduction from a standard concrete mix.

Reduced carbon footprint

This composition has resulted in the wind farm’s carbon footprint being reduced to approximately 90.7kg of carbon dioxide per cubic meter. Ground Granulated Corex Slag (GGCS), a by-product from the iron industry, is used to replace 89% of the cement.

“Cement manufacturing is typically a highly energy intensive process. By substituting the cement with a by-product such as GGCS, we are able to reduce our carbon footprint considerably,” said Leo Quinn, Project Manager for Loeriesfontein Wind Farm.

A twenty-eight day compressive strength test has been completed, which indicated that the 80% replacement ratio achieved an impressive strength of 55MPa (megapascals), and an expected ultimate strength of 100MPa, within a fifty-six day period.

Adding energy to the national grid

Loeriesfontein Wind Farm is situated within the Hantam Municipality and will comprise 61 wind turbines each with an output of 140MW and will generate approximately 563 500 MWh/year of clean, renewable energy to the national grid.

The wind farm will avoid approximately 550 000 tonnes of carbon emissions each year when compared to traditional fossil fuel power plants and generate enough to power around 120 000 average South African households.