Across Australia most new solar installations are subject to tariffs which pay the owners as little as 1/4 or less for their excess power that they export to the grid during the day than they are charged for using the same power through the evening hours.

Installing a battery system in your home allows you to instead store this excess electricity and use it yourself, avoiding the high tariffs.

Components for solar storage systems

1. PV Solar Panels – per a traditional system, roof mounted panels generate DC electricity
2. Inverter – converts DC electricity from the panels into AC that is either used in the home by appliances or fed back into the grid
3. Charge Controller – controls charging of the batteries. DC power from the solar panels is sent to the batteries whilst they are below capacity.
4. Batteries  – used to store the excess power generated by the solar panels.

Battery Technologies

The three most commonly used battery chemistries for residential energy storage are Lead Acid, Lithium-Ion and Lithium Iron Phosphate.

Battery Chemistry	Characteristics
Lead Acid	Oldest rechargable battery technology Low energy to weight ratio Inexpensive Handles high surge currents
Lithium Ion	Most common cylindrical battery type
Lithium Iron Phosphate (LiFePO4)	Improved cycle life over Li-ion Constant discharge voltage up to exhaustion Slightly lower energy density than Li-ion

Battery / Energy Storage System Manufacturers

A number of systems as listed below are already available on the Australian market which can be purchased and installed today.

These products commonly include some or all of the components required to provide fully automated local energy storage solution.

Manufacturer	Battery Chemistry	Product details
Neeo System	Lithium-ion	Capacity: 5 – 27.5 kWh
Samsung SDI – ESS	Lithium-Ion	Capacity: 3.6 – 5.8 kWh
Nedap – PowerRouter	Lead Acid & Lithium-ion options	Capacity: 3 – 5 kWh Origin: Netherlands
Magellan Power – Residential Energy Storage	Lithium Iron Phosphate	Capacity: 9.2 – 13.8 kWh Origin: Australia
Bosch	Lithium-ion	Capacity: 4.4 – 13.2 kWh Max input/output:  2.5 – 5 kW
BYD – Dess	Lithium Iron Phosphate	Capacity: 8 – 16 kWh Max input/output: 3 – 9 kW Origin: China
Selectronic – myGrid	Lead Acid	Capacity: 8 – 80 kWh Max input / output: 3 – 20 kW Origin: Australia
BenQ Solar – PowerLegato	Lithium ion	Capacity: 2.4 – 7.2 kWh Origin: China
CMS Group	Lead Acid	Capacity: 5 – 15 kWh Origin: Australia
Redflow	Zinc Bromine	Capacity: 8 kWh Max input / output: 5 kW Origin: Australia
Enphase	Lithium Iron Phosphate	Capacity: 1.2 kWh modules Max input / output: 275 – 550 W Origin: USA Note: New product not yet available.
Zen Energy Systems	Lithium Iron Phosphate	Capacity: 10 – 20 kWh Max input / output: 5 kW Origin: Australia
Sunverge / Sunpower	-	Note: New product not yet available but widely reported for 2015 release in Australia.

Installers

Company	Location	Battery Technology Supported
Aussie Solar	Sydney, NSW	CMS Group
Solar Australia	Regional NSW	Selectronic, BYD
Lumenaus	VIC	Nedap PowerRouter
Going Solar	VIC	Selectronic
Dynamic Solar	Central West NSW	Bosch, Magellan Power
The Greenpower Company	VIC	Selectronic
The Sun Works	Southeast QLD	Enphase, Samsun, PowerLegato, Bosch
All Energy HQ	QLD	BYD

 

Online retailers

Company	Location	Battery Technologies Sold
Apollo Energy	Australia Wide	Bosch, AUO PowerLegato
Sunergy	VIC	Nedap PowerRouter, Selectronic

Economics

Grid connected solar + storage makes economic sense (being a commercial return on investment) for some niche cases now and without doubt will do for the broader market within the next 10 years.

For households that installed solar whilst feed in tariffs were at or above current peak usage tariffs it’s unlikely to make sense to install storage yet. All feed in tariffs were time limited and most run out within 2 years from now. By this time the battery cost will have come down, the supply side of the market will have improved and it will be a good time to consider installing local storage.

Just as solar panels have experienced rapid cost reductions over the last 5-10 years, the consensus is that battery prices will see similar declines.

For households installing a new solar PV system now or who are on feed in tariffs well below their usage tariffs – solar may already be viable.

Regulation & Electricity Companies

To date there has been limited reaction from the power companies to consumers installing local energy storage systems. The adoption levels to date are very very low and so the lack of reaction is not surprising.

As has been widely reported the rapid adoption of solar is causing enormous amounts of very rapid change in an industry that is accustomed to the opposite. As consumers we have grown used to a very reliable supply of electricity, delivering this requires very rigid control of the networks, extensive levels of redundancies and great deal of forward looking long term planning.

There is already discussion of a shift in the weighting from usage based to fixed monthly access charges and it should not be assumed that such changes won’t occur in future.

Solar Hot Water

Whilst perhaps not immediately obvious, solar hot water already offers the opportunity for grid connected energy storage. It is well entrenched and highly unlikely to be effected by tariff changes in future. It should be a starting point for users wanting to install local storage.