So on Engineering News, Chris Herold, a Renewable Energy skeptic, asked: "Really, you can get electricity out of solar PV from 6 am to 10 pm? You must be living in a parallel universe where the sun shines at different times. And what will you do during peak periods? The biggest evening peak is after sunset. Solar energy is also pretty weak during the morning peak (even worse during winter in Cape Town). All you would achieve is to double the capital cost of overall generating capacity, since we would still need to invest in REAL base load generation. PPP - Peak Power Parasite."
And this is my answer:
Yes really :) An average 3 bedroom 4 person middle class household use 1200 kWh per month. * 12 months / 365 days / 5 average peak sun hours gives an 8 KW grid tie PV system. In July 2012, this family will be paying R1800 per month including VAT for their electricity. R182,400 at 10% per annum over 20 years is R1800 per month!! At R22.80 per watt, 8 KW is R182,400 which is R1800 per month. ie pay the CoCT R1800 per month for electricity or use Net Metering any pay R1800 per month for your PV system.
Then get more clever. Invest R60,000 reducing your electricity requirement by 70%. This means that one needs a 3 KW system. Total price R120,000 or R1200 per month or R1 per kWh instead of R1.50 per kWh.
Then get the Eskom ESCO rebate of 42 cents per kWh at peak time and 10 cents per kWh at off peak time and this equates to R29 per 10% saving in electricity per house per month, ie another R290 off making the per kWh price 82 cents instead of R1.50.
Then use this difference to put in Vanadium Redox battery banks and Ultra-Capacitors and Hydrogen Fuel Cells and load shedding and smart metering systems for households and you have a more localised, reliable system at a cost that Eskom and the Cities can't match. And Eskom pays people who load shed more than 1 MW within 1 second of notification and you have a system which costs less than 82 cents per kWh.