The solar system that leaves competition in the shade

3 min

2018 saw unprecedented growth in large-scale solar PV with nearly two gigawatts (GW) of new capacity registered with AEMO. More than two thirds of this capacity came from solar systems that actually track and follow the movements of the sun.

Millions of Australian consumers are embracing and utilising rooftop solar energy in homes across the country, and increasingly taking control of their energy consumption. But it’s also a flourishing time for large scale commercial solar or utility-scale solar system(s). For example, in 2018, AEMO had nearly 2 GW of new capacity registered via these larger scale systems.

But what actually constitutes a utility-scale solar system? According to Greentech Media, it can be defined as, ‘A utility-scale solar facility is one which generates solar power and feeds it into the grid, supplying a utility with energy. Virtually every utility-scale solar facility has a power purchase agreement (PPA) with a utility, guaranteeing a market for its energy for a fixed term of time.’

This growth in utility-scale systems has been largely attributable to single axis tracking solar. Unlike conventional, fixed axis systems, single axis solar systems have panels that tilt around a north-south axis to follow the sun – they face east in the morning, are horizontal at solar noon and face west in the evening.

Single axis systems, or tracking solar systems, have grown rapidly to become the dominant technology for utility-scale solar in the National Electricity Market (NEM). They offer new benefits to the system in terms of greater output and higher summer capacity. They also capture more direct solar radiation for longer periods of the day which gives them a flatter profile and a higher overall capacity factor (the percentage of actual electrical output out of the total possible output of a generation asset).

Interestingly, single axis systems can make a meaningful contribution to meeting peak demand in mornings and evenings during summertime. The downside of this, however, is that as the sun sets output starts to fall quite rapidly. It’s also noteworthy that both single axis and fixed axis systems are less effective in winter due to the shorter daylight/sunlight hours. And at some sites in the NEM, single-axis tracking systems produce less winter midday output than fixed-axis systems.

Today, there is approximately 1750 megawatts (MW) of tracking and 800 MW of fixed solar capacity registered with AEMO, and the vast majority of upcoming connections are also expected to be single axis systems. With technology advancing, and increasingly hot summers on the horizon, it looks as if the growth period for utility scale solar systems and single axis technology in particular will continue for some time to come. 

*As the system and market operator, we are fuel and technology neutral. The products, services and providers in this content are for illustrative purposes only and are not endorsed by AEMO. AEMO and its officers and employees are not liable for any statement or omission in this content.

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