Securing water supply to your home when there are interruptions was the topic of our previous article, in this, our final article, we consider going off the grid. That means supplying all your own water and electricity.
Depending on the size of the household, estimates are in the region of R250 000 to take a small house completely off Eskom’s grid. This estimate is based on a house with 3-4 people who use approximately 25 kWh per day.
An off-grid solar system is not connected to the electricity grid. All the energy available to the home is from the solar system and available immediately via an inverter or stored in batteries to be used when energy is needed.
Off-grid solar system sizing or specifications are determined by two measures:
As a rough guideline, daily watt-hour usage can be calculated from utility bills or more accurately by energy metering data loggers. Refer to how solar systems work
Batteries will be one of the main costs of your off-grid PV system. The batteries used for off-grid systems are the same as those used for hybrid systems. For a comparison between Lithium Iron and Lead Acid batteries, see our article on inverters and batteries.
Because 100% of your home’s energy is being drawn from batteries, you may need to make small changes in usage patterns to prevent running out of power or damaging the batteries. More details are provided in the full Guide which you may download below.
To save costs on additional battery storage, it might make financial sense to keep the hybrid style of solar system, rather than going off-grid.
Going off the grid waterwise, you can harvest rainwater or sink a borehole.
If you are lucky enough to have sufficient storage space for rainwater (i.e., ± 30 kl) or a borehole that yields a constant supply, a small water treatment plant can treat the water to a quality suitable for drinking purposes.
Water that doesn’t come from the municipality must undergo testing at a qualified laboratory and meet the South African National Standard SANS241.
That concludes our 13-part series on sustainable living with facts, figures, advice and tips on how to be a savvy homeowner and take more control of your utility supply.