Australian Weather

18 Apr 2024, 3:20AM UTC

A weeklong stretch of low wind power was broken on Wednesday evening, as a weak cold front marched across southern Australia.  The chart below shows that the National Electricity Market (NEM) has endured a weeklong stretch of low wind generation, with wind power providing around 6% of the NEM’s electricity, down from last year’s average of 13.1% (Mon, April 15 to Wed, April 17).    The daily wind generation has been under 41 GWh/day for the last seven days leading up to Thursday, April 18. The calmest winds occurred on Sunday, April 14 with only 24 GWh/day produced or 4.6% of grid demand.   To put this in perspective, the average daily wind generation during the last year up to Wednesday, April 17, 2024, was 71 GWh/day, according to data from the open NEM.  This prolonged period of low wind was caused by blocking high pressure systems sitting over southern Australia, forcing cold fronts or strong wind further south.  The image below shows the Mean Sea Level Pressure chart on the calmest day, Sunday, April 14, with high pressure stubbornly sitting over the southern half of the country.  Image: Mean Sea Level Pressure Analysis at 4am AEST on Sunday, April 14. Source: Bureau of Meteorology.  As we mentioned earlier today, a positive Southern Annular Mode (SAM) has led to consistent high pressure systems positioned over latitudes well south of Australia during the first three months of the year and during this week. This has kept cold fronts south of the mainland, and even south of Tasmania.   READ MORE: WHAT IS THE SAM?   The period of light winds ended abruptly on Wednesday evening, with WattClarity reporting that wind production peaking above 3,000 MW at 9:10pm AEST.  The increased wind power on Wednesday night, was caused by a couple of factors;  A weak cold front swept across the southeast on Wednesday, bringing stronger winds.  A very shallow temperature inversion formed in the early evening protecting the surface from the stronger winds, but the wind turbine hub-height (150 metres above the ground) winds remained strong at around 28-38 km/h in SA.  Temperature inversions form at night when the ground cools quicker than the air above it, meaning that the temperature increases with height for a thin layer of the atmosphere.   During autumn, the temperature inversions are commonly shallow meaning that while the wind could be weak at the surface, the hub heights could continue to experience strong winds.  A similar phenomenon could happen again tonight across southern Australia, with another cold front passing across the south.  Looking ahead, light winds are expected to continue from Friday as a stubborn high-pressure system builds over the Bight until early to mid-next week.   

03 Apr 2024, 4:35AM UTC

Southern Australia saw an abundance of clear skies during March, causing rooftop solar to soar to new heights.  The run of sunny days was caused by blocking high pressure systems that prevented cloud and rain bearing cold fronts from sweeping across southern Australia.   The clear skies led to Melbourne recording its driest March on record with a measly 2.8mm total, beating the previous record of 3.7mm in March 1934. Adelaide was also dry, recording 27 days without a drop of rain, while Sydney picked up 52.5mm of rain and Brisbane 152.8mm.   Across the four major NEM capital cities:  Melbourne saw its sunniest March in 18 years, with an average of 8.5 hours of sunlight each day.  Adelaide recorded the sunniest March since 1994, averaging 10.4 hours of sunshine per day.  Sydney observed an average of 7 hours of sunlight per day, which is the most sun hours the city has seen in two years.  Brisbane was the cloudiest of these cities with only 5.7 hours of sunshine on average per day, consistent with above average rain falling in the city.   The lack of cloud and rain across southern Australia led to increased rooftop solar output across the region in March 2024.   Data from OpenNEM shows that rooftop solar in Victoria was the highest on record this March since rooftops installations begun in 2007. The graphs below show the warm season rooftop solar contribution to the National Electricity Market (NEM).  Images: Warm season (October- March) rooftop solar power (GW/h). Data sourced: OpenNEM, AEMO, APVI.  The rising trend in the graph above for VIC looks remarkably similar for SA, with March 2024 producing 294 GWh / month across the state, compared to 252 GWh / month from March 2023.  The graph also highlights that the total solar generation has been increasing year-on-year since 2018, driven by a boom in solar installations across Australia.  The Clean Energy Council reported that in 2023, renewable energy supplied a record 39.4% of Australia's electricity, led by wind's 13.4% share. Rooftop solar cracked a 10% share for the first time, reaching 11.2% ahead of solar farms at 7% and hydro's 6.5% share.  During March 2024, rooftop solar across SA supplied 24.5% of SA’s energy needs, the largest in the NEM. Meanwhile renewable energy contributed 77% of SA’s power, with wind taking the lead with a 43.5% contribution.  Image: March contribution to renewables in SA, Vic, NSW, Qld, Data sourced: OpenNEM, AEMO, APVI.  Rooftop solar is the leading renewable across NSW and Qld, contributing between 11 and 12 percent to the state's energy needs, followed by solar farms then wind.  Weatherzone Business and Solcast are a market-leading partnership delivering highly specialised solar data to the Australian renewable energy industry.  Designed for utility scale solar sites, we offer you a globally proven solution.  With low upfront CAPEX and powerful cloud-based information systems, you can access a complete suite of irradiance and weather data to ensure forecast accuracy and improve site efficiency.  Solcast is the world leader in real-time actuals and rapid-update solar forecasts. This solution utilises Solcast’s centralised Amazon Web Services’ (AWS) cloud infrastructure for all complex algorithmic processes and data plumbing. You will gain the power of AWS to interpret and deliver your data at top speed, providing real-time, historical and forecasting estimates direct to your API.  Receive monitoring and support from the Weatherzone and Solcast teams, 24/7. For more information, please contact us at business@weatherzone.com.au.