Renewables hit more than 80 pct of grid demand for first time – despite heavy throttling of wind and solar

Renewable energy has broken through another key milestone on Australia’s main grid, meeting more than 80 per cent of demand for the first time on Saturday afternoon, and could have met all of demand and more were it not for heavy curtailment of wind and solar.

It ended up being a weekend of records, with rooftop PV hitting new milestones, operational demand hitting new lows across the main grid and in several key states, and curtailment of large scale wind and solar also reaching new peaks.

According to various data sources, renewable energy as a share of total demand reached 80.5 per cent at 12.25 pm on Saturday afternoon (one data source put it at 81.5 per cent), breaking the previous record of 79.6 per cent that had been set just a day earlier.

The record might have been a lot higher: More than one half of available wind output was being curtailed and nearly half of large scale output was being curtailed, despite near record levels of storage, particularly from the growing fleet of big batteries on the grid.

The curtailment occurred because rooftop solar was meeting more than half of demand, and the grid is not yet ready to meet 100 per cent renewables, which would require all coal and gas fired generation to be switched off. That won’t happen until the market operator is satisfied that grid forming inverters can meet all the system security needs.

And coal fired generators went about as low as they can go without being switched off – which they don’t like doing – and were reduced to a share of just 18.8 per cent of demand. So something had to give.

Geoff Eldridge, from GE Nemlog, described the event as a significant milestone for the National Electricity Market – the formal name for the country’s main grid that covers most of Queensland, NSW, Victoria, South Australia and Tasmania.

Eldridge says that at 12:30pm on Saturday, approximately 8.42 GW of large scale wind and solar output, about equal amounts of wind and solar. Curtailment happens because of economic reasons (wind and solar farms choose not to operate when prices are below zero), and because of grid congestion or maintenance.

“By 13:50 AEST, the NEM had already curtailed around 54.8 GWh of renewable energy, while flexible loads absorbed around 22.5 GWh, including about 17.3 GWh into batteries and about 5.2 GWh into pumped hydro,” he noted in a post on LinkedIn.

He also noted that there would have been a significant absorption capacity of behind-the-meter home batteries.

“So during the first interval in which renewables exceeded 80% of NEM consumption, the system was simultaneously:

• supplying more than four-fifths of consumption from renewables and storage
• reducing coal to less than one-fifth of consumption
• absorbing more than 5.3 GW of flexible load
• charging batteries at around 4.5 GW
• and curtailing another 8.4 GW of available renewable output

“That combination is becoming an increasingly important part of the NEM transition story.

“It is no longer simply: more renewables means less coal. Increasingly it is: more renewables share → less thermal generation share + much larger flexible loads + batteries absorbing surplus energy + significant renewable curtailment

“And today, for the first time, that transition took renewable supply beyond 80% of NEM consumption.”

Updated: As it turned out, the levels of curtailment were even greater on Sunday, when it hit a record peak of 11,109 MW at 11.55 AEST – beating the previous record set a year ago by more than 250 MW.

It was part of a confluence of events driven by mild spring weather, very high levels of renewables, and rooftop PV in particular, and record lows for operational demand across the main grid.

As Eldridge noted in a new post on Monday:

At 12:55 AEST, when NEM market demand reached its record low of 9,072 MW, underlying native demand was still 30,648 MW, while rooftop PV was producing about 16,714 MW.

This provides useful context for the minimum-demand conditions. The record was not simply associated with exceptionally weak underlying consumption; a large share of demand was being met away from the operational grid.

The midday sequence provides a useful view of the conditions:

11:55 — NEM curtailment: 11,109 MW, record
12:00 — NEM rooftop PV: 16,993 MW, record
12:00 — Queensland rooftop PV: 5,380 MW, record
12:55 — NEM market demand: 9,072 MW, record low

Sunday’s minimum-demand conditions coincided with subdued spring Sunday consumption, record rooftop solar and exceptionally high renewable availability.

To join more than 29,000 others and get the latest clean energy news delivered straight to your inbox, for free, click here to subscribe to our free daily newsletter.

To support independent media, and help combat the spread of deliberate misinformation and disinformation about the energy transition, you can click here to make a one off donation or become a regular supporter of Renew Economy.