While the option to capture and store solar energy has been around for a couple of years, the price of batteries and related components has been very high and the use and maintenance of the equipment has been quite complicated. This has meant residential energy storage has been largely confined to those who were truly “off the grid” or those who were hard core solar enthusiasts.
Recent reductions in price and the evolution of lithium-ion batteries has now put solar storage well and truly back on the radar! The new generation of solar batteries are more affordable, provide a better ROI and are far more compact and aesthetic than the older styles.
Many of the new systems are “set and forget” systems which require almost no upkeep and will run for years. At Solar Mad we have been receiving an unprecedented amount of inquiries about battery storage over the first few months of 2017. It’s a very hot topic!
Lithium-ion based residential energy storage has been around for a couple of years but the system that has created a solar storage ‘revolution’ is the Tesla Powerwall which incorporates new-age lithium ion batteries.
These batteries power all sorts of devices (power tools, laptop computers, mobile phones etc) and have many advantages over traditional lead acid batteries including:
- Much lighter weight and more compact
- Higher energy density
- Low self-discharge
- Lower maintenance
- No “memory effect”
- Greatly increased cycle life
Many systems have a UPS (uninterrupted power supply) function, so that in event of a power blackout, the UPS will support designated backup circuits and most can operate in four different modes, depending on the customer’s needs:
- Solar: During the day, solar power is drawn directly from the PV panel and excess energy is diverted into the batteries.
- Battery: When there is no direct sunlight shining on the PV panels, energy is drawn from of the batteries.
- Grid backup: When there is a blackout, energy is drawn from emergency battery reserves just for prioritised electrical circuits such as the fridge and appliances.
- Load shifting: store energy during the time of the day when usage is normally lowest so you can use it when electricity consumption is highest.
Battery driven energy storage is quite a simple concept, but involves some very high-tech equipment and this diagram shows how residential battery storage works using the Tesla Powerwall system.