Tips on how to Prepare for a Transition to Solar Power
Establish Energy requirements: If planning a transition to solar, you need to know how much electricity you currently use, as this will determine the size of the solar system that you may require. The easiest way to get a figure for this would be to take an average of one’s monthly electricity Units (kWh’s) used (from your Eskom or Municipal bill) over a 12 month period, and divide this by 30 to give you an estimate of kWh’s/day. This is one’s average daily Energy requirement, and this will be what the solar system needs to provide.
Establish Power requirement: The next step would be to do a power audit for the house - add up the power ratings (usually located on a small sticker, in Watts or kW’s) of all appliances, and lights, that might potentially be switched on at the same time. This will give one a rough idea of what size inverter your solar system will need.
High-power and energy-hungry appliances (anything rated in kWatts as opposed to Watts) should be avoided, or replaced with non-electric options, if at all possible. The most common thing requiring a change is an electric geyser. These are often around 3kW and will often run for at least 4-6 hours daily. So changing this load to either LPG or a solar geyser will remove this entirely from the electrical equation.
All lighting should be changed to LED versions of whatever bulbs are currently in use. Incandescent bulbs generate a lot more heat than light, and as a result are extremely inefficient and use far more electricity than they need to. The equivalent LED bulbs will use roughly a tenth of the electricity as an incandescent, as very little heat is produced. As a result, they also last a lot longer. I would avoid using the ‘energy-saver’ fluorescent bulbs too, as they are not as efficient as LED’s, contain harmful chemicals, and just don’t last very long.
Become aware. Reducing wasteful behaviour needs to become par for the course, for living on solar power. Shifting heavy loads to the middle of the day, when the solar system is bringing in most of its power, is also very helpful, and reduces unnecessary strain on one’s battery. Things like washing machines and dishwashers should preferably be used during daylight hours.
Any loads that can operate during the day only, e.g. a pool pump, can be put on a timer switch to ensure that these run when the system is generating power, and not running off the battery, at night.
On-demand LPG geyser
This heats up the water ‘on demand’ as there is no tank, only the hot water required is heated as needed. These are much more economical than electric geysers, but they do still use a fossil fuel in LPG.
A Gas geyser on its own, ties one into using a fossil fuel, and a solar geyser, on its own, will not give you hot water security, ie. if you have a few days of heavy cloud and rain, you won’t have hot water.
So the absolute ideal for minimising use of fossil fuels, and having hot water security, would be to have a solar geyser with a gas geyser inline, closest to the delivery point of the house. The newer models of Paloma, Rinnai and Bosch have temperature sensors on the water inlet, and only turn on when the incoming water from the solar geyser is not quite hot enough. Best of both worlds!
Please note that these suggestions are to try to reduce the overall load that a solar system might need to provide. It is quite possible for solar systems to provide as much power as you need, but the cost will escalate accordingly. It is not sensible to be wasteful with electricity and thereby necessitate a huge solar system, which will obviously cost a whole lot more, and take longer to pay for itself.
BUT, one also finds that when the sun is shining, there is often a surplus of power, because one would usually spec a system to provide enough electricity, even in inclement weather. Bear in mind that Green electricity is the cleanest energy you can use (ie. from a solar system, or other renewable source). So, to have parallel systems in place is very handy, if the budget allows.
For example, using an electric kettle is great, when the sun is shining nicely and the power from your panels would otherwise be wasted. But when your panels haven’t seen the sun for a few days, and your battery should be saved for night time usage, then one would rather use the stove-top kettle on the gas stove instead. Same goes for an electric geyser - a gas geyser could be put inline, and only switched on when the solar system can’t provide what’s needed. This does, however, require attentive management.