How to Optimise Solar Energy During Load Shedding Period

<...in the event of grid failure...if solar output comes down...make the internal consumption equal to the solar generation...>

Er, ah, um, this is illogical. When the equipment is off-grid then, regardless of actual sunshine levels, the load consumption in the absence of storage will always be equal to the solar generation less, of course, any conversion losses inherent in operating the equipment! The only way it could be more involves using up storage, such as that contained in the <...battery...>.

These fora usually encourage users to do their own market research using search engines such as Google (usual disclaimer).

No wonder 16.6kW is needed.

Thanks for recommending the site and it is really informative.

However, I will appreciate if you could recommend a cheaper model for load shedding controller for a 10kW solar hybrid power system.

Thanks.

So why exactly can't the sources be turned off or put into a non power producing standby mode?

The cheapest would be a simple voltmeter and a bank of on/off switches...

I'm getting the strong impression that actually turning off the power sources to keep them from overloading the drain side of the system is not something he wants to discus.

'Ignore it and it and people will stop asking about it.' sort of thing.

Quite.

So why can't you just turn the solar power supply off or just use what part of its output you need?

Pretty sure they don't blow up of they are not running at peak power output every second the sun is shining.

Just because you have the capacity to do something doesn't mean you have to use all that capacity all the time. Especially with solar power.

This is simpler, if you add more batteries or storage modules as buffer system.

This is an interesting problem with some complications. We have solar, diesel generators as well as grid based electricity. Due to local municipal regulations we block any energy going back into the grid. (Worst case, we will get charged for feeding into the grid.) We therefore generate as much as we can, throttle if we go over demand and supplement with the grid.

If the grid goes down for any reason - load shedding (reason for the diesel generators) or grid maintennance, we have to stop using solar energy as this creates a safety risk for anyone who might be working on the supposed to be "dead" circuit. This goes against my intuition, but our electrical specialists and local municipal regulations are adament.

Check with your local municipal authorities how they address this issue and stay safe.

Andries

Clearly, your inter-connect may not be appropriate. It is supposed to isolate the solar/diesel gen-sets from the grid source during outage of the grid, so no "back-feed" takes places. That is the hazard.

You could install some extra light bulbs around if you just have to "waste" some power.

More batteries in the battery bank makes good sense, also.

So during normal use, are you mostly using your local sources, then pulling in just that power from the grid that is needed for full production?

Depending on the climate where you live, you could consider using excess solar power to either add or remove heat from a large thermal sink, perhaps a phase change material. Heating up water in a well insulated extra (electric) water heater would be an easy fairly cheap and useful load in which to shed. Making ice, or chilling brine might also be useful, but would be more complicated in reaping benefits.

If you have a swimming pool, you could shed a huge amount in there heating or cooling the water.

Thank a lot for your detailed reply.

Having thought some about your problem, the following may be your best option..

1. Feed a suitable inverter direct from your battery to power the vital loads, which may require new circuits/distribution board for these loads. Provision for bypass to mains may be automatic/short break/uninterruptible [UPS]/manual [move plug to another socket!!] according to risk & cost.
2. Hand switching of other necessary circuits to a supplementary,hand-energised, inverter, according to battery capacity and practicality - remembering that your actual experience may modify what is "practical" - start "simple/small", which is less cost & time.
3. Remember that some kinds of loads, particularly refrigerators may be difficult to start from an inverter, even if other equipment does not mind voltage dips. Also friges start when they need to - not to suit your sensitive power supply. It may be possible to use for vital stuff, a domestic "no-motor" frige (resistive), which does not have a starting surge - caravan units may even work from DC direct.