This is easy. Subject to a few reasonable assumptions, the RET subsidy on solar installations in Adelaide is $700 per Kilowatt. So removal of the Renewable Energy Certificates (RECs) will raise the cost of a 3 Kw system by $2,100 and a 5 Kw system by $3,500, for example.
Most customers are blissfully unaware of the RECs they receive for a solar installation, as they are almost invariably signed over to the supplier as an effective discount. So nearly all the advertised prices you see are post REC discount.
There have been varied percentage claims, from a 20 to 80 per cent price rise tipped if the REC system is abolished. This is because the RECs awarded to an installation are based solely on capacity, not quality. The cheapest and the most expensive systems are all equally subsidized. Additional equipment, such as monitors and storage units do not attract any REC subsidy.
The RECs that apply to household and small business solar installations are called Small Technology Certificates. An explanation and calculator can be found at http://retaustralia.com.au/rec-calculator/. Heavy polluters, such as coal-fired generators are required to purchase certificates quarterly or pay a penalty. The price per REC fluctuates, but the market for RECs is heavily regulated with the value capped at $40 per certificate. They often sit around $35 each and this is a commonly accepted value used when discounting solar installations.
Whether the RET and therefore the RECs are abolished or reduced by the current government remains to be seen. If you’ve been hanging back watching solar technology steadily get cheaper, this may be a good time to invest in your future power consumption.