Rooftop solar power in South Australia has one of the fastest growth rates in the world: one in every four households is equipped with a photovoltaic system. Demand for solar power has been driven in great part by the soaring electricity prices in South Australia, now among the highest in the world. In addition, the Small-Scale Renewable Energy Scheme from the Australian government provides cash rebates in the form of Small-Scale Technology Credits (STC). These credits decrease the cost of a solar installation by over $650 per kilowatt, as of late 2017.
Solar photovoltaic systems reach their peak productivity around noon. Small-scale rooftop PV systems add up a total capacity of more than 700 MW in South Australia, and in October 2017 their total output reached a peak value of 538.54 MW, with represented a record-breaking 48% of total generation at the time when it occurred.
In September, the lowest demand experienced by the power network had been 786.4 MW, due to the influence of solar generation. However, this was reduced to only 587.8 MW in October. In fact, solar generation has changed the demand profile for the power network in South Australia: The lowest demand generally occurred at night, but now solar power is bringing daytime demand even lower.
The rapid growth of solar power in South Australia means one thing: homeowners and companies consider it a viable alternative to purchasing all their electricity from energy retailers, who have doubled their rates in less than a decade. For example, most electricity prices in Australia increased by 20% in July 2017.
Future projections for solar power are very promising. With current trends, the Australian Energy Market Operator estimates that daytime demand in South Australia will reach a minimum value of only 354 MW by the year 2019. It may be reduced to zero before 2030 as more homes and businesses deploy solar power.
The main technological challenge to overcome is meeting nighttime consumption with a resource that is only available during the day. However, lithium-ion batteries are a promising solution: as an investment, they break even with the current electricity prices in South Australia, but consider that batteries will only get cheaper, while electricity gets more expensive. A report from the Turnbull government states that distributed solar power and energy storage could account for 40% of overall generation in Australia within the next decade. Also consider that batteries are not the only way to store surplus electricity from solar photovoltaic systems – you can also install a high-efficiency heat pump and store hot water for nighttime use.
Exporting surplus electricity from solar panels to the local network is also a possibility, and Australian energy retailers recently increased their feed-in tariffs. However, the FIT is only around one-third of the retail price of electricity, so it makes sense to consume or store all the output of solar array if possible – each kWh is worth three times more!