What does it take to go off the grid?

With the impact of load shedding increasing and the consensus being that things will get worse before they get better, many South Africans are looking to reduce their reliance on Eskom.

Experts agree that the best way to produce your own power is to use solar panels to generate electricity and a lithium-ion battery to store it. An off-grid system does however come with a substantial price tag, ranging from R150,000 to more than R650,000, depending on the size of the installation.

On the other side of the scale, the ever-increasing cost of energy in South Africa means that it is still economically viable to go off the grid if you can afford the initial capital outlay. According to GreenCape, the cost of a solar system can be recouped within a five-year period.

The cost of a system, including installation, that is sufficient to power a three-bedroom, two-bathroom home using around 25 kWh per day is between R200,000 and R250,000. A premium system for a larger home giving you complete independence could cost upwards of R650,000.

Before you decide on a system design, you should perform an energy-efficiency audit in your home. By making changes that makes your home more energy-efficient, you reduce the capacity needed, which in turn will reduce the cost of your system.

You can start by changing the appliances that uses the most electricity to alternative options. Converting your electrical oven to a gas option and your hot-water geyser to a solar or gas geyser will have a significant impact. Replacing older appliances (refrigerator, freezer, washing machine, dishwasher) with newer, more energy-efficient models, and switching all lights to LED options, is the next step in the process.

Factors that come into consideration when designing a system include size (power and capacity), roof details (size and pitch of roof with sun exposure), autonomy (how long the system must provide power during periods of low generation) and your budget.

The essential components of an off-grid system include the following:

Solar panels

Solar photovoltaic (PV) panels convert solar energy to electrical energy. Solar panels comprise of several solar cells. The most cost-effective panels contain between 60 and 72 cells and a standard 60-cell panel will provide 300 to 375 watts. In South African conditions solar panels are best mounted on a north-facing pitched roof to maximise exposure to sunlight. Modern solar panels last between 25 and 40 years.

Charger control

The direct current (DC) power produced by the solar panels is directed through the charger control to the battery bank where it is stored. The charger control is a critical component because it determines the efficiency of the solar system. The charger control ensures that the batteries are charged correctly and protects them from being over-charged. The charger control also eliminates any reverse current flow from the batteries back to the solar modules during period where there is no sunlight.

Inverter

The function of an inverter is to convert the DC current from solar panels into alternating current (AC) so that the electricity can be used by electrical appliances. A good quality inverter ensures stable electricity without fluctuations that could be harmful to your appliances. Inverters come in various sizes to fit with system requirements. High-end inverters are multi-functional units that combine charge controllers, battery management, seamless switchover from different power sources and computerised operation. The expected lifetime of an inverter is between 10 and 15 years.

Battery bank

The battery bank is the most expensive component of any off-grid solar system. Excess energy produced during the day is stored in a battery bank to provide electricity when there is no sunlight. The two most used battery types in solar installations are lithium-ion and lead acid. A lithium-ion battery has many advantages over lead-acid batteries and is most recommended for off-grid applications. High-end lithium-ion batteries come with a 10-year guarantee.

Absa provides the following tips for choosing a solar system installer:

Experience and references

Do they have a proven and established track record and experience? They should be able to provide references of previous projects and installations.

Qualified staff

Do they employ or subcontract qualified electricians? Ask for proof of registration from the electrician (also called a wireman’s licence) and validate.

Home visits

The installer should be able to produce a simulation or feasibility study, of the electricity production estimate for the system for a year with average weather, based on a physical site visit and advise on the size of your components (solar panels, inverter and batteries) to meet your household consumption.

Technical expertise

Are they able to demonstrate their technical capabilities and know-how, on how to install a solution that meets your electricity requirements? For example, are they able to advise on the best position for your solar panels to obtain maximum exposure to the sun during the day?

Rules and regulations

Do they understand the municipal and Eskom’s by-laws and process for installations in households?

Post-installation service

Do they have an after-sales service or offer maintenance contracts? If so, what are the service level agreements?

Warranties/Guarantees

Do they provide necessary warranties and guarantees both for the installation and for the various equipment/components of the system (solar panels, inverter, battery and the structure of the system)? Compare these with that of the manufacturer’s warranties and guarantees.

Optional: PV GreenCard certification

Do they have a PV GreenCard certificate? A PV GreenCard is a certification that has been developed to promote safe and high-quality solar PV installations.

The information contained in this article is of a general nature and intended for information purposes only. It is neither to be construed as financial advice nor to be regarded as a definitive analysis of any financial, legal or other issue. Individuals must not rely on this information to make a financial or investment decision. Before making any decision, we recommend you consult your financial planner/adviser to take into account your particular investment objectives, financial situation and individual needs.

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