Grid Tie Solutions
DC power generated from the PV modules is converted from a fluctuating DC voltage to 220V/380V grid connected power. Grid systems do not store energy and thus do not have backup. If grid failure occurs no power will be produced from the system. Grid systems are easy to monitor and measure performance as there are no storage losses. Grid inverters are very efficient and very few losses will occur in high quality grid systems.
Multi Hybrid Solutions
This system consists of 2 alternative energy systems working together. An island system secures backup power to the “essential” appliances. A DC Coupled or Grid-connected system feeds power to both the essential and non-essential appliances. The topology of a multi hybrid system allows it to function as a full island system under grid failure, ensuring an unlimited power supply to all the essentials. As the grid-connected PV system is usually sized to serve both the essential and non-essential appliances, it is well over-sized in case of grid failure to supply the essential appliances. As the batteries will only cycle in case of grid failure, standby batteries can be used that can achieve similar life to that of cyclic batteries but are far more cost effective. Battery backup is then only sized for essential appliances and therefore significantly less than typical off-grid Applications. Generator integration also possible.
Off Grid (Island) Power Solution
Energy Generated from the PV modules is used by inverters to produce 220Vac power. Surplus power is stored in the batteries to ensure power availability when usage exceeds PV production. Battery storage is sized in order to achieve 1 to 3 days autonomy. As the batteries will be working on a daily basis, cyclic batteries should ideally be used . True hybrid inverters have the ability to select how it will interact with grid supply. If grid supply is in the form of national grid, a true hybrid inverter can be programmed to ignore the dedicated supply and only accept due to low battery or load exceeding inverter specification. In the case of generator supply it can manage the generator and can be programmed not to overdraw the generator. True hybrid inverters are expandable in parallel and three phase.
