Remote power generation systems have used off-grid storage for many years in outback Australia. In most cases the system is built around a diesel engine generator with battery back-up. In more recent times, with the reduction in price of solar panels, a new type of hybrid remote power system has emerged that integrates a solar PV array with a battery. In most cases a diesel generator is still required because the battery itself does not have the capacity to store enough energy use for more than a day or so. The combined solar-battery-diesel hybrid yields a lower cost of electricity than a simple diesel generator because of the reduction in maintenance and shipments of diesel fuel.
Such systems typically require a solar array with matching inverter to convert the DC power from the solar panels to AC power.
A separate inverter-charger is needed to accommodate the battery. The inverter charger also allows the diesel generator to be coupled.
Example battery inverter-chargers are the SMA Sunny Island, the Selectronics SP-Pro and the Schneider Electric SW and XW inverters and charge controllers.
experienced engineers such as LC Energy have been involved in off-grid for many years
there are lots of systems in the field
reliability is critical for off-grid customres
system design is flexible (single and three-phase options available)
systems are highly configurable but can be complex with training required
the best sysems are remotely monitored to give the user peace-of-mind
There are three types of grid-connected storage system.
1. Classical approach
This is essentially the same as the off-grid system except the diesel generator back-up is replaced by the grid.
2. Hybrid system using inverters and batteries
This system has emerged over the past 2-3 years. It combines a solar inverter and separate battery inverter/charger in one enclosure
The system has been the storage product that has been favoured by solar inverter manufacturers
Note that the Tesla PowerWall and other high voltage DC battery products require separate inverters to enable them to be integrated with existing PV systems.
LC Energy has installed systems that employ lead-acid systems supplied by
3. Energy Storage Systems
The third type of storage system is a the ‘appliance’ approach where the manufacturer has combined a solar inverter, battery inverter and battery in one enclosure
The system is easy to install, and is an easy for the owner to understand. A single badge on the product means that there is only one company to turn to for warranty and service support.
Unfortunately this approach suffers in terms of flexibility compared with the other methods.
Examples are the Bosch BPT-S Hybrid 4.4kWh and the Samsung All-in-one 3.6kWh systems.
What battery type?
LC Energy is experienced in designing and installing systems with different battery types. What works best depends on the expected lifetime, cycle duration and ultimately cost. We are experienced in using lead-acid gel batteries, sodium batteries and various lithium ion batteries from different manufacturers. We have an association with BYD for supplying systems for residential storage applications.