Is it possible to get off the grid (electricity) completely? – Yes. However we need to make sure that certain items are removed completely from the need for solar electricity. Eliminate any possibility of cooking on photo voltaic power (PV), hot water of any sort (geyser, electric kettle), and you then make a start of getting off the grid with solar panels, batteries and inverter (to create 220 volt power from whatever DC voltage you choose from you batteries.
I have a 3 bedroom house in the dessert, gas oven & hob, usual appliances (fridge, TV, computer, hair dryer, kettle, toaster), standard lights and plugs, solar geyser – how many solar panels would I need to get off the grid and how many batteries? – For a two child, two adult household two kilowatts (8 x 250 watt panels) should suffice.
What other components would I need? – Batteries, to store enough power for refrigeration and lighting overnight, a voltage controller to prevent the panels from overcharging the batteries, and an inverter.
Could I do this piecemeal, one room at a time. If I started in the kitchen alone what components would I need and what would the cost be? – Piecemeal: Not advisable. Unless one spends less on batteries for now and adds to this aspect later. One does not want to re-invest in a new inverter because you find that the one you have chosen does not cope etc.
What is the cost of each battery and the cost of each solar panel? – Get a quote from your nearest Water Rhapsody franchisee
Would I need my house to be rewired? – If this is a retrofit consider placing a green plug (from PV) next to each municipal electricity supply.
Would an electrician need to do this? – This could be done by an electrician or by us.
Where must the batteries be stored? – Batteries must be placed in a well-ventilated area. Also somewhere that could take the weight of these. These could weigh up to 400 kilograms and if deep cycle batteries are used a lot more!
Must the solar panels be on the roof? – No, but if one has a north facing roof, this is a convenient spot. These may be placed on poles which is useful too as one can follow the sun by literally rotating the panels to get the best efficiency all day long.
What’s the answer to question 2 if I live in Newlands against the mountain? – Literally measure the daylight hours for the area and calculate this proportionately.
When the time comes how do I go grid – tied? – Good question!!! We are monitoring this one with interest. Different city councils are tackling the issue in different ways. Cape Town for example have started with corporates and will in the future allow all homes to be grid ties according to an interview with Patricia de Lille on Cape Talk in Sept 2014.
Can you show me a diagram of how it all works?
How long to install? – Three to 10 days depending on the complexity.
Whats the payoff period using Cape Town electricity prices? – Depends on current tariffs. Talk to your nearest Water Rhapsody franchisee
How long do the batteries last? – three to five years for standard sealed lead acid batteries. For more money one could go for gel batteries 5 – 7 years, and dry cell batteries even longer, but best practice at this stage is lead acid.
How long do the solar panels last? – This is the great part: in excess ln 20 years.
If Eskom’s price increase by 25% annually, how would this affect the payoff. – This is a major factor. However if one looks at where the crossover of the falling prices of renewables vs. the rising price of fossil fuels was: five years ago, the price of panels has fallen by 60% and electricity tariffs by 150%.
What the single biggest reason to use solar electricity? – The answer is twofold: a hedge against inflation and indemnity against electricity outages.
What are the limitations? – First find the money to install!
Is technology making them cheaper? – There is no doubt of that whatsoever.