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Switching over to photovoltaic power

There is also growing pressure for us to adopt renewable energy as a means to lessen our impact on the environment and our reliance on fossil fuels. One of the key ways in which residential, commercial and industrial energy users are looking to ease their electricity costs as well as better secure their energy supply is through photovoltaic (PV) electricity generation.


Load shedding, blackouts and power shortages are going to be part our lives for years to come. Recent outages and the return of load shedding have served as a sharp reminder that we are still operating off an inadequate electricity infrastructure, and that our capacity reserves have dropped from 40% to about 6% this year, way below the international norm of 15% that allows for routine maintenance and closures.

We have become complacent about a steadily deteriorating situation. At the same time, rapidly escalating electricity prices at the current rate are simply unsustainable and unaffordable for many. There is also growing pressure for us to adopt renewable energy as a means to lessen our impact on the environment and our reliance on fossil fuels. One of the key ways is through photovoltaic (PV) electricity generation.

What is rooftop PV?

A rooftop photovoltaic power station, or rooftop PV system, is a photovoltaic system that has its electricity-generating solar panels mounted on the rooftop of a residential or commercial building or structure. Solar panels, which consist of solar cells, 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 and that power gets synchronised with the Eskom grid and allows it to be fed into the network and supplies you with electricity.

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 from local utility.

Planning for a PV system will require you to analyse your electricity use, implement energy efficiency measures, study local council codes and feed-in requirements (if any), 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 and supplier to help you meet your objectives.

Why PV?

Many clients like the appeal of a grid-tie PV system which allows them to use PV during the daylight hours to power their homes and businesses – and then to switch over to grid electricity at night. If you consider that most businesses have their peak demand during the day when they operate, and many homes have processes like washing, ironing, mowing, pool pumps and so on taking place during the day, then using the energy form the sun during the day makes great financial sense. A grid-tie system allows you to perform all your daytime activities for free, powered by the sun, and save on the more costly battery back-up needed to store PV electricity to use at night time. Many businesses also use PV in conjunction with other power sources like diesel generators to provide a continuous source of power.

Depending on your electricity usage and size of your PV system, most will amortise their costs within five to seven years. This is the very best investment you can make right now to safeguard your supply, your productivity, your safety and most of all take control of rapidly escalating electricity costs for years to come.

Why do I need to implement energy efficiency measures beforehand?

Implementing energy efficiency measures in your existing home or business 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 usually your biggest electricity users to solar or heat pumps, installing LED low energy lighting, using gas for cooking, putting movement and day/night sensors on office lighting 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. Energy efficiency in buildings is no longer just the preserve of those wanting to do the right thing. What was a voluntary standard has been written into law in the SANS 10400-XA: Energy Usage in Buildings, and SANS 204: Energy Efficiency in buildings. This requires a focused solution for areas such as water heating, whereby 50% of all hot water in new houses needs to be produced by methods other than electrical element heating.





Analysing your electricity needs

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 over the year to manage peak demands.
  •  Energy saving measures you can implement to reduce your electricity use and thus save on costs for the PV system 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 and machinery. 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.

Codes and Regulations

Each municipality handles the connection of PV systems to the grid differently. Yet, as the price of electricity continues to increase, more municipalities are entertaining the idea of connecting solar PV systems to their grid. The words net-metering and feed-in-tariff are commonly used in conjunction with PV systems but consideration of your municipal office is required.

Each region has its own set of codes and regulations that you will need to follow to add a PV system to your home or business. It will determine whether you decide to connect your system to the electricity grid or use it in place of grid-supplied electricity. You can also plan your system to take advantage of future expected changes to feed-in tariffs which are very likely given Eskom’s supply challenges and need for grid relief.

Types of PV Connections

Consider these alternatives - A solar PV system with:

  •  System 1 - No batteries, grid connected system
  •  System 2 - Some batteries, grid connected system
  •  System 3 - Only batteries, no grid connection

System 1 is used to supplement your energy usage. In the event of a blackout or power outage, your solar system is forced to shut down. Therefore, even if the outage occurs in the middle of the day during full sunlight hours - no power will be produced. If net-metering is allowed, this type of system provides a one for one credit on your monthly electricity statement.

System 2 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 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.

System 3 is useful for areas where no grid exists. The energy produced will charge up the batteries which should allow for 3 days’ worth of energy needs and these batteries will feed the power requirements of the property.

It is important to note that adding batteries adds to the cost and therefore the systems are ranked from the least expensive to the most expensive.

What is the cost to install PV?

There are various aspects that play a role when we look at the cost, obviously the size/scale of the system. The advantage of solar is the long life expectancy. If we look at a typical solar plant, your initial capital layout would be in the beginning when you purchase the equipment and on average takes between 5-7 years to offset the costs, but then for the expected 25 years or more 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.

Typically, a 4kW system which is usually sufficient for an average household (without battery banks as per system 1 above) would cost in the region of R75k and could easily be funded on our monthly repayment option for around R2100 per month depending on your selected payback period and credit rating. Your electricity savings are very likely going to cover most of your monthly loan payment as well. On a 4kW config as per system 2 with battery backup, costs would start in the region of R125k. 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.

Site visits and energy audits are necessary in order to provide costs on larger systems for commercial operations, which One Energy also provides.

How can One Energy help you?

Assessing the potential for energy savings and prioritising key areas for improvement through renewable energy can be a challenging task if one does not know where to start from. The skills of One Energy’s experienced renewable energy professionals provide enormous value in this process.

We offer an extensive range of renewable energy technology to firstly make your building more efficient, and once we have done your energy measurement and audit, we’ll design a PV system for power generation. We provide retrofits for existing buildings, through to completely new installations. We handle projects from small rooftop solutions for residential clients, right through to large scale commercial and industrial PV projects.

We provide monthly finance options for smaller residential and commercial clients who can offset the capital costs against their electricity savings, as well as fully bankable PV solutions with lease agreements for very large industrial and commercial projects.

There is no more crucial time to take control of your energy needs and supply. Renewable is the only way to go – for your finances, your security, your productivity, the environment and your peace of mind!

Opinion by Teresa Kok, Director at One Energy (Boksburg)



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