Photovoltaic (PV) systems make use of the sun to generate electricity during daylight hours. And because solar is a technology and not a fuel, there are no ongoing costs after installation as is the case with gas for example. Right now, solar delivers at least an 18-25% return on investment each year based on electricity savings, far outstripping any other investment vehicle where you could place your money. Investing in solar to save on your electricity costs is a no-brainer, and the very best investment you can make right now for your business or home for the next 20-25 years.

What is rooftop PV?

A rooftop photovoltaic (PV) system has its electricity-generating solar panels mounted on the rooftop of a building or structure. Solar panels are exposed to sunlight or solar radiation and generate electricity which is called a photovoltaic effect. This solar power flows via cable to a device called an inverter which converts the direct current (produced from the panels) to alternating current. With the inverters synchronising the solar power and the Eskom grid, that power can be fed directly into your internal electrical network and save electricity. So every KWh generated by the solar system is a kWh less required from Eskom or local municipality.

PV installation residential
How to choose the right solar partner

Planning for PV

Planning for a PV system will require you to analyse your electricity use, implement energy efficiency measures, decide if you want to operate your system entirely off grid or use a hybrid or grid-connected solution, and then finally select, the technologies to help you meet your objectives. And because your system is going to be working for the next 25 years, you need to be sure about working with a supplier that has the network, financial stability, product quality and warranties in place to maximise your investment. Reputation, credibility and the expertise of your renewable energy partner are fundamental to you realising the maximum benefit from your PV investment.

Why do I need to implement energy efficiency measures beforehand?

Implementing energy efficiency measures before you buy your PV system will reduce your electricity use and allow you to buy a smaller and less expensive system. For example, converting geysers which are your biggest electricity users to solar or heat pumps, installing LED low energy lighting, using gas for cooking, installing lighting motion sensors and so on. If you’re designing a new building, consider working with the architect and builder to incorporate renewable energy solutions into your design from the outset. In fact, some measures are already legislated. SANS 10400-XA: Energy Usage in Buildings, and SANS 204: Energy Efficiency in buildings requires a focused solution for areas such as water heating, whereby 50% of all hot water in new buildings needs to be produced by methods other than electrical element heating.

Analysing your electricity needs – No shooting in the dark

Calculating your electricity needs is the first step towards getting PV ready. A thorough examination of your electricity needs helps you determine the following:

  • The size and cost of the system you will need.
  • Fluctuations in your energy usage during the day and night and over the months to manage peak demands.
  • Energy saving measures you can implement to reduce your electricity use before installing PV so that you save on the costs of a bigger system simply by being more efficient.

By conducting a load analysis, One Energy will record the wattage and average daily use of all of the electrical devices that are plugged into your central power source such as refrigerators, lights, televisions, PCs, power tools, machinery and computer equipment. Some loads, like your refrigerator or electric fencing, use electricity all the time, while others, like power tools or large format printers, use electricity intermittently, known as selectable loads.

Some providers will ask you only for an electricity bill and attempt to provide a PV solution based on this, but the approach is fundamentally flawed and inaccurate since your bill cannot reveal day and night usage, selective loads or peak demands which need to be factored into your PV solution. A thorough load analysis is a must. We’ll visit your premises, set-up loggers on your electricity distribution board for at least a week to ten days, and provide you with a comprehensive view of where your electricity usage is going, and what steps we can take to help you reduce it. We will also be able to provide a very accurate indication of what your savings will be depending on what size system and the solutions we specify for you, so there is no shooting in the dark.

Types of PV Connections
A solar PV system typically comes in three configurations


System 1 Grid Tie
– No batteries, grid connected. This system supplements your grid energy usage and is a very good option for reducing your electricity usage from the grid. In the event of a blackout or power outage, your solar system is forced to shut down. However, given that Eskom outages are not the issue, but cost savings are, this is a highly practical solution to dramatically reduce your electricity bill by producing all your daytime energy requirements, free from the sun, and avoiding the additional expense of a battery system. A Grid tie system is highly cost-effective and has a much shorter payback period (ie: starts paying for itself from day 1).

System 2 Hybrid
– Batteries and a grid connection, and is commonly referred to as a hybrid system and with the correct installation will act as a UPS (uninterrupted power supply) in the event of a power outage. The PV system will charge up the batteries first and then the excess production will supplement your household/ business energy needs. Many of our clients start with system 1 with a plan to build up to a system 2 and then add battery back-up at a later stage as their budget allows to build up to a system 2 configuration. The great benefit of solar PV is that it’s entirely scalable and you can add to it as your needs grow. Clients typically opt for this when power outages are an ongoing issue.


System 3 Island
– Only batteries, no grid connection, useful for areas where no grid exists, such as farms or remote areas. The energy produced will charge up the batteries which should allow for three days’ worth of energy needs and these batteries will feed the power requirements of the property.

What is the cost to install PV?

Many people believe renewable energy is too expensive without actually doing their homework. The reality is that the cost of renewable energy solutions has come down significantly over the last few years. When we take them through the costs versus the savings and the fact that their savings can even finance their move to renewable energy, most are stunned at how absolutely affordable it is. In fact, on a monthly repayment option, in many cases the monthly finance payments are covered by what they would be paying on electricity costs anyway. Once paid off, you’ll be smiling even more!

If we look at a typical PV system, your initial capital layout would be in the beginning when you purchase the equipment and on average takes around 5 years to offset the costs, but then for the expected 25 years of the lifespan of your panels, you will get free electricity. The initial upfront cost is the only cost involved with solar. After that, because there are no moving parts, the maintenance on the system is very low. Once fully paid, you have an incredible investment and asset for your property that keeps saving you thousands of Rands each year, for many years to come. And you’ll have a highly efficient, green home or business which is an absolute win. Another advantage of PV is that it is entirely scalable and can be ramped up as your requirements demand and, more importantly, as your budget allows.

PV benefits

Solar PV has a range of benefits. Systems focused primarily on savings (grid tied systems) immediately reduce your electricity bill pro rata to the size of the system you install. Back-up systems, which provide during power outages, provide clean, quiet, instant and environmentally friendly electricity when your utility lets you down. Hybrid solutions provide back-up with a measure of savings. The true benefit of Grid-tie Solar PV (focused on savings) is the fact that you are protected from future Eskom price increases. Any component of your electricity requirement covered by a solar system is in effect hedged against future tariff escalations. All indications are that South African electricity users are in transition from enjoying the lowest cost of electricity in the world ten years ago to becoming one of the highest payers.