With electricity price hikes on the cards and load reduction being implemented, more people are thinking about gaining independence from the national grid with alternative energy sources, like solar, to power their lives. Switching to solar makes sense if applied for the correct reasons. South Africa has an ideal climate with around seven hours of sunlight a day. Using the sun’s energy which is clean, unlimited and quiet, solar power systems that are planned aesthetically have very little impact on the environment, so it suits companies and people who have green goals. Though the sun’s energy is free, the photovoltaic panels and associated systems that collect it, and especially those meant to store it, require a considerable investment.
This is why Nick Oosthuizen, Managing Director at Inframid, advises companies and homeowners thinking of making the switch to first plan and then buy.
“Don’t just jump in. First, understand your reasons for wanting solar power. Is it to save on overall energy costs, is it to provide backup power during load shedding, or is it a bit of both? You also need to know what your energy demand profile is and what type of system you would need to meet your needs. Solar power systems are a serious investment, and the worst thing you can do is overcapitalise. You will not see a return on your investment if you do.”
He explains that as a backup in the event of power failures, solar systems will normally be connected as a typical uninterrupted power supply. This needs storage capacity to supply enough energy to cover the load for the planned back-up period.
“If your reason for installing solar is to provide backup power, you will need to buy large enough batteries to provide capacity for the average load reduction outage of three to four hours. For this purpose, it is important to compare the cost of different backup technologies, such as petrol, diesel, gas and battery. There could be cheaper backup power options for you.”
To save on electricity costs, both grid-tied and off-grid systems are options. Off-grid systems work entirely independent from the national electricity grid, which means they need ample battery storage to provide backup during low solar irradiation. The idea of being “off-the-grid” is enticing for frustrated South Africans being hit with regular load reductions and power outages. However, Oosthuizen says these systems must be planned carefully, especially in terms of cost, and keep in mind that it will take some time to see returns.
If your need is to save on electricity costs, grid-tied solar systems are the most common because they are cost-effective, the easiest to install and need the least amount of equipment which means they have fewer points of failure. They are connected parallel to the grid and the load, thus being exposed to the total load, meaning that the solar system has the best chance of applying its total capacity to the load, therefore used in a feasible manner.
“To save on energy costs, a grid-tied system is a good option. Depending on the size of the system, the installation and how you use it, you could see impressive savings on your monthly electricity bill. A grid-tied system won’t help you if your reason for wanting solar power is for backup, unless you have another backup system to carry your load demand during power outages,” explains Oosthuizen. He adds that hybrids of grid-tied and off-grid systems are also available. These must, without doubt, be planned and configured correctly.
The feasibility of a solar generator that is intended as an investment, based on cost savings, strongly relies on the following aspects:
Providing it with sufficient day-time base load on a day-to-day basis. It is for this reason that a grid tied solution should opt for having the total load exposed to its generation capacity. The challenge is then to shift as much of your load as possible to day-time, either by means of operational management measures or automated load control;
Ensuring a high-quality plant that will be able to deliver the planned capacity for 20-plus years. This should be an important focal point of the procurement process; and
Ensuring that dedicated maintenance is built into your long-term business plan, avoiding unplanned costs. This is the reason why long term life-cycle management should be included into the procurement process.
Aside from helping to reduce energy costs and reliance on the national grid, grid-tied systems also offer the potential to provide passive income for businesses that feed excess solar power they generate with their photovoltaic systems to the utility. Utility supply in South Africa is progressing with the process of setting up the legal, technical, metering and tariff framework for the connection of small-scale generation to the low voltage network.
Oosthuizen says it is preferred to allow between six and 12 months of metering time, across all seasons, to measure electricity usage and determine a feasible solar system size needed to tend to the energy demand. A feasibility study is worth the effort to get an accurate picture of how much energy is used and what it costs over these periods.
“Other things to consider include practical considerations such as the type of roof on the building or house. Is it strong enough to accommodate the solar panels? And, does it face the right direction to capture sufficient sunlight? If not, you need to plan for providing more solar capacity,” adds Oosthuizen.
With this in mind, he says that developers should allow for future solar infrastructure when planning new builds.
“Certainly, achieving some independence from the national grid is becoming critical for an increasing number of South Africans. Many of us are also concerned about the environment and choosing renewable energy sources like solar is healthier for it.
“Advances in solar technologies mean that the sun’s energy is a reliable source of power, especially in South Africa, where we are blessed with sunlight, even in winter. Nevertheless, a solar investment must be carefully considered to ensure that it addresses the reason for the installation feasibly. Rather be conservative. Take the time to do the metering to ensure that you invest in the most appropriate system architecture for your needs,” concludes Oosthuizen.