If you have a solar system that produces more energy than you can use then having a battery allows you to store this energy and use it at night when the sun isn’t shining. The financial benefits of this are that you pay around 25 cents per unit for electricity you use and only receive around 7 cents per unit of energy you export to the grid. By having a battery large enough to power your household energy requirements and a solar system large enough to charge the battery daily you can potentially never have to pay for electricity again. Please note that there are still grid connection fees you can’t avoid!
The TESLA powerwall is a battery most people in or out of the solar business have heard of but there are multiple other options on the market these days too. We have researched the market and options available for you and provide a solution for single phase houses and for three phase houses.
BYD is a factory founded in 1995 that has grown to a giant in the field of batteries, automobiles, solar panels and various other products. Their specialty though is rechargeable batteries. For solar storage solutions, they use the Lithium Iron Phosphate chemistry and have a stack solution where you can add modules depending on the storage energy you require or desire. The stacks are made of 2.76 kWH packets. You can add from 8.28 kWH up to 22.08 kWH in total. This is the most reliable, affordable and modifiable battery system we have found for 3-phase houses. For single phase houses we recommend consideration of the ALPHA eSTORE integrated system but the BYD stack can still be used if you desire greater than 10 kWH of stored energy. This battery stack system works particularly well when integrated with the FRONIUS hybrid inverter. Click here to see an informative article by PV-magazine on this combination. Due to recent changes in the rebate being dropped to 3 cents per unit of energy you produce, battery storage is becoming more attractive. The STCs are still very generous and if you have a 3 phase house then you can load up your house with as many panels as you can and get a subsidy for every panel you install. However, you forfeit the 3c/unit feed in tariff if you go over 5kW but if you are storing this energy in a large battery and use the majority of it at night then this is of little concern.
The POWERWALL 2 from TESLA is the best known battery for solar energy storage worldwide for good reason. It is arguably the most advanced system that can be adapted to any solar system, whether 3-phase or single phase. It can be installed at the time the solar system is installed or it can be added later. You can also add this battery even if you don’t have solar. The POWERWALL connects to the grid, the solar system and the battery through a module known as the GATEWAY. It allows you unparalleled control of your system for monitoring and also for modification of charging and discharging times and parameters. The POWERWALL will operate in the even of a grid failure. Each POWERWALL 2 has 14kWh of energy storage of which 13.5kWH can be used. You can add more if you require additional storage. The POWERWALL can discharge at a high rate to power most appliances in your house, 5kW continuous and 7kW peak. Each POWERWALL battery costs $10,000. The GATEWAY is an additional $2000 and installation is $2000. Additional batteries do not require additional GATEWAY modules.
The ALPHA eSTORE system is a battery storage system suited to single phase houses that incorporates a Goodwe inverter, 10.3 kWh battery storage and a UPS. This system is very neat with all components integrated into a single unit. The UPS allows the battery to operate if grid power is lost. This is perhaps the most cost-effective and reliable solution for residential houses with 2-5 occupants who want to store the solar energy harvested by the solar panel system during the day and use it at night rather than purchasing from Synergy.