A PhD candidate at the University of South Australia has found domestic solar batteries can pay for themselves within the warranty period for some South Australians.
Vanika Sharma of UniSA’s School of Engineering found that this is because of the unique conditions in the state, including the Home Battery Scheme.
Residents can now take advantage of SA’s combination of government subsidies, abundant sunshine, high electricity costs and relatively low feed-in tariffs (FiTs). Together they make a solar battery financially attractive – if it’s the right size and price.
Domestic solar batteries: Choosing the right one
However, Sharma says batteries are not yet cost-effective in all residential cases.
She has developed a unique method to calculate battery cost-effectiveness. This uses a range of factor which allow consumers to measure their investment against projected savings.
It also factors in load and PV generation patterns as well as battery cost, type, retail price and available grid feed-in tariff. People can then determine the size and type of solar battery that suits them best.
The current break-even cost for domestic solar battery installation in SA is around $400 per kWh of battery capacity, Sharma’s thesis states. Government subsidies of $500 per kWh and retail battery prices lower than $900 per kWh all contribute to make a cost-effective investment.
Research calculates battery savings
Sharma published her paper in Renewable Energy journal along with co-researchers Dr Mohammed Haque and Professor Mahfuz Aziz.
She set out to solve a problem encountered in many homes seeking net zero energy (NZE). The homeowner still has to pay an annual electricity bill because imported energy from the grid is usually more expensive than exported energy from solar panels.
Consumers can solve the problem by installing domestic solar battery storage. As a result they exchange less energy with the grid.
Meanwhile, the paper details a method to determine optimum battery size for a typical SA home with solar panels. It does this using:
- Hourly load and solar PV generation data in SA
- Annual battery repayment and interest rates
- Retail price and FiT.
Community and shared batteries also on cards
UniSA team members are also researching alternatives to domestic solar batteries. This includes shared community energy storage.
According to Sharma, the aim is to reduce solar energy waste. This can happen through home batteries like Tesla Powerwall 2 and Enphase or using central battery storage.
A central battery could save distribution costs for providers. Ultimately, it could also help improve operation of the grid.
