Preventing Energy Backflow to grid on hybrid system

[barnabyrees-jones]

I need some help with a technical difficulty in the installation of solar PV in South Africa. Is there a way of preventing back flow into the grid of excess solar energy? As in placing a diode or an Automatic Transfer Switch into the system between the meter and the distribution board?

The current system in South Africa doesn't favour renewable generation and you are actually charged for energy fed back into the grid (meters aren't bi-directional and have anti-tamper systems that trip when fiddled with or reverse energy go through them which can only be re-engaged by the energy board coming out and plugging a code in) so I need a solution that will physically prevent back flow?

Also, If hybrid solar system is installed, the daytime solar PV will be consumed for the background loads in the house and excess energy fed into the batteries. Once the batteries are full, what happens to excess energy?

I want the hybrid with storage setup so that the system will work should the grid go down so with backup power.

What hybrid system/battery storage have people found the most successful so far?

Thanks,
Barns

[inetdog]

There is no simple add-on device that will do this. You would have to essentially install a power meter and use the sign of its output to control the grid connection or throttle back the hybrid inverter output.

The good news is that (almost?) all packaged hybrid inverter systems include just such a device and have a simple configuration setting you can use to tell them not to try to sell power back to the grid.

Systems from Xantrex (Siemens), Outback and SMA, among others, have this feature.

[Mike90250]

Xantrex XW gear is made/sold by Schneider Electric (not Siemens)

http://www.schneider-electric.com/en/product-range/7654-conext-xw-/

The Mfg site will have info on the several models for export in your country. However, any hybrid system will require a battery bank, which is another large additional expense