Semloji

It's relatively simple Put a current sense on your grid side, electronics must monitor amps and if it exceeds rating of your system the grid contactor must drop out. Mean while power continues thru the inverter powered contactor to the house load. the fact that the grid is down means that south africa is demanding power from you, excessive load. when you set the trip current it must supply the house and excess to the grid but any more than that it must drop the grid contactor out and protect the inverter and electricians working on the line. Extra electronics can be used to monitor a balance. IE Load is using 10A, inverter is supplying 20A and grid is taking 10A. 3 current sensors. now grid voltage goes down from eskom supply and grid becomes intensive load to your system. amp are up current load becomes excessive, contactor drops out. Now you monitor the grid voltage to see its down on the town side of the contactor. Make the contactor only pull back in when the town side voltage comes back up. It's a combination connect and disconnect for different reasons thru 2 or 3 contactors. Just remember when all contactors are out, voltages can be picked up on both sides of the contactors to signal your electronics or power your contactors on when you want them on and off. when all contactors are in it acts as one line, so breaking the line momentarily and sensing voltage as there or not will work. As soon as the voltage is back from Eskom that contactor or relay in back in. Flip flop contactors can also be used and there are more angles that can be wangled out but at more cost and parts. hope this helps

Trash Incineration is the Most Expensive Way to Make EnergyVariable O&M costs include fuel and other consumable materials and supplies; raw water; waste and wastewater disposal expenses; purchased power (incurred inversely to operating hours), demand charges and related utilities; chemicals, catalysts and gases; ammonia for selective catalytic reduction (SCR), as applicable; and lubricants. Source: "Updated Capital Cost Estimates for Utility Scale Electricity Generating Plants,"

Here's something else Eskom may have to deal with in the future The combination of low demand and strong output from the Queensland

baseload fallacy. EDF in UK has today begun unplanned shut down of 4 nukes = 8GW = 10% of total UK energy demand for 8 weeks to fix a fault. The national grid operator said they can cope because "a lot of wind power is being generated right now". (Ft.com). This turns the wind=intermittency/nuclear=baseload argument on its head. Thanks to wind Power

Have a look at this, "Municipalities owe Eskom more than R10bn - Gordhan" http://www.polity.org.za/article/municipalities-owe-eskom-more-than-r10bn-gordhan-2014-08-11 I was supprised to find Western Cape Gov and Cape Town in the mix, owing so much. This also causes the prices to go up to carry the costs.

Lovely one. Dont forget the stem wall to be built to keep the home warm in winter and cool in summer without any power. also the fruit drying roof trays and power gen chimney in any new builds Add the bio digester to provide hot water cooking gas and black gold (liquid fertilizer for the garden) you can see a drop off on your graph, must be change to winter sun, or loss on panels settleing in ??? It would be interesting to see change as summer comes in.