A sharp fall in cost and a switch to PERC technology has transformed the economics for developers of large-scale solar projects, writes Rystad Energy senior analyst renewables Australia David Dixon.

Australian solar farms predominantly utilise PV modules with silicon solar cells, a technology which has rapidly evolved over just a few short years. The crux of this change is the development of the type of solar wafer used (mono- or multi-crystalline) and the advancement of cell design (Al-BSF vs PERC).

It is important to note that module efficiency, and therefore module power, is critical to the capex of a utility solar farm. The number and size of modules will determine the number of piles, the number of trackers, the amount of wiring and the time required to install each of these components.

An increase in module power reduces the number of modules needed, in turn generating significant cost savings on hardware and installation work. This is particularly important in Australia, where labour rates for installation services are comparatively high. (It should be noted that around 11% of utility-scale PV farms in the country utilise thin film solar modules, comprised of cells made of cadmium telluride rather than silicon.)

The first wave of utility-scale projects centered on multi-crystalline Al-BSF modules, offering lower costs but also lower output. At the time of purchase (2016-18), there was a significant price gap between the higher and lower efficiency modules, and the increase in output did not justify the extra cost.

However, the price of modules plummeted late last year, falling by nearly 50% on a per-watt basis versus comparative prices in 2016. With only a few cents per watt separating the higher and lower efficiency modules, the market flipped to the more efficient PERC design.

This switch is seen most clearly in the utility PV farms expected to be commissioned in 2020, the majority of which will use PERC design, offering a significantly higher output than any year prior.

The top 10 module suppliers in the Australian solar market have varying strategies with regard to panel technology. Some firms, such as Longi and Sunpower, have chosen to focus on panels utilising higher efficiency mono-crystalline cells. Others, such as Canadian Solar and Risen, have to date only supplied multi-crystalline modules.

Additionally, the market is clearly shifting towards the PERC cell design as the cost discrepancy between PERC and Al-BSF narrows, yet there is currently no obvious winner in the mono vs multi-crystalline wafer debate.

LCOE variance

Among Australian utility solar farms with more than 20MW capacity, average module power has risen significantly since 2016, when it stood at about 315W, and is projected to average some 373W in 2020. This has also coincided with module prices plummeting from more than $US0.40/watt in 2016 to less than $US0.25/watt in 2019.

Rystad Energy has calculated a range of LCOE’s for various module types and AC capacity factors (25.5% to 33.8%), representing different parts of Australia’s National Energy Market (NEM).

In our base case, the results show an LCOE reduction from $70 to $55/MWh. However, the LCOE range varies greatly depending on capacity factors and cost uncertainties.

David Dixon is senior analyst, Australia renewables research at Rystad Energy.