How regulating efficiency in motors can help stabilise SA’s power supply

03 October 2019 | Web Article Number: ME201916298

Electrical & Electronics
Motors, Drives & Transmissions
Power Generation
How regulating efficiency in motors can help stabilise SA’s power supply

SOUTH Africa could go a long way towards cutting the risk of future load-shedding by adopting a minimum efficiency performance standard (MEPS) for electric motors.

That’s according to Fanie Steyn, Manager Rotating Machines at Zest WEG Group, who said a MEPS would significantly reduce the peak power demand on the national grid. Importantly, the step could be made at no cost to government and would also bring substantial savings to industry’s electrical energy costs.

“The MEPS would phase out the least-efficient electric motor classes by setting a minimum standard for the efficiency of motors imported and sold in South Africa. The essential challenge now is that about 280,000 electric motors are imported each year, many of which are low efficiency motors rated at IE1 level as standard.”

Steyn said great strides had recently been achieved in the efficiency of electric motors. Energy savings of between 2,1% and 12,4%, depending on the individual power rating, can be made by converting from a standard efficiency IE1 motor to a premium efficiency IE3 motor.

He added that the capital cost differential is slight and is quickly recouped by lower operating costs.

“It is estimated that as much as 30% of all energy produced globally is consumed by electric motors. It is therefore easy to see why improving motor efficiencies has a huge impact on national energy consumption.”

According to Steyn. more than 42 countries already have MEPS in place. These standards apply mostly to three-phase low voltage motors from 0,75 kW to 375 kW capacity. The MEPS is applied at import stage, so the process would be handled in the conventional manner by customs agencies.

“If the 150,000 low voltage motors entering the country each year were IE3 rated instead of IE1, the national grid could be relieved of about 195 million kWh in a single year. This means almost three billion kWh over the next five years.”

This, he said, would also mean lower carbon emissions from power stations. South Africa has committed to reduce these emissions by signing the Paris Agreement in 2016.

“Implementing MEPS will have significant benefits for everyone.”

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