What is Load Shedding and Why It Is Happening in South Australia?

ABC News reported that South Australian residents have been warned that they could face power cuts as the state struggles to meet their power supply demands.

As Adelaide experienced a severe heatwave and the mercury tipped at 42 degrees Celsius, 90,000 homes had their power cut off for 45 minutes because there was not enough supply to meet the demand. This process is called load shedding.

Load shedding happens when the Australian Energy Market Operator (AEMO) orders power companies within Australia to start switching off customers’ power supply because of a risk in the power system.

The system always has to remain in balance between supply and demand and if there’s no extra supply available, the top boys have no choice but to reduce demand by shutting them off. If they don’t do load shedding, the entire system can fail and cause a statewide blackout similar to what happened in South Australia in September 2016.

On February 8th, the AEMO predicted that there was more demand than the available supply and the major Heywood Interconnector was importing power from Victoria close to its limit. The wholesale power prices were at peak at $14,000 megawatt-hour and AEMO called for more power stations to offer electricity into the market but some of them did not comply.

With the existing interconnector that includes Victoria, South Australia has more than enough power generation to cover demand even on the most extreme days. But many experts say that a large and expanding proportion of that generation is from intermittent renewable sources like solar and wind. When there’s no wind, the market operator cannot direct wind farms to provide power.

The Heywood Interconnector was just expanded to allow greater power flow into or out of the state, but still, has a limit of 600 megawatts. The electricity market in South Australia had been tighter since the closure of the state’s sole coal-fired power plant in Port Augusta last year.

The AEMO has predicted lack of power reserves across this summer and every summer for that matter until the additional supply is added to the mix.

Now, why is the Federal Government blaming renewables for the power shortage? South Australia has one of the highest mixes of solar and wind energy in the world. It can also be said and argued that the onset of high levels of renewable energy have helped bring down the wholesale prices in South Australia.

With subsidies through renewable certificates, the wind farms can produce and provide power at a much lower price as compared to the traditional coal and gas generators. But this flooding of cheap renewable energy has helped in the hastening of the closures of thermal generators.

Many politicians and some experts believe that with fewer traditional gas and coal generators in the market, South Australia will have less capacity to generate energy on demand. This will be an issue whenever demand is high and there is no wind.

Click here to read the full story on ABC News

Featured Image Credit: Bernard Spragg. NZ