Nic Roets

Ok. I managed to set up that integration on my Pi running HA.
Then set up polling of the power sensor at 5 second intervals and got this graph.
I guess I'll now be able to write code to shutdown overloaded circuits. It will run on the Pi, so I need to make sure the Wifi is as reliable as possible.

We're a 3 storey building with 45 apartments in Pretoria East. Each apartment get's municipal power, most of them on a post paid basis. Some flats use as little as 200 kWh per month, while other go up to 500 kWh.
Some residents are so fed up with load shedding that they are considering buying battery backup systems costing R3,000+ each.
I think we need to consider a central battery bank to achieve economies of scale. Then supply one socket in each apartment with reliable power. Installing electrical cables is a major hurdle, but that's our problem.
We also have 10+ parking bays getting plenty of sun. We can build car ports with solar panels on top.
At this stage, I just want to draft a discussion document for circulation.
If we aim to supply each flat with 200 W, then it's 9 kW total. Add some spare capacity then we need 3 x 5 kW of inverters. (R70,000)
18 kWh of battery backup to supply us during 2 hours of load shedding. (R125,000)
10 kW of solar panels (R70,000)
10 kW MPPT (R21,000)
45 power monitors so that we can detect if someone is overloading the circuit and / or bill residents (R18,000).
Total R304,000
According to pvwatts.nrel.gov, this system will generate 17000 kWh/Year, saving us R34,000. So the hardware will pay for itself over approximately 10 years.
What have I missed ? How realistic is this calculation ?