Questions & considerations on solar installation and power generation

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20th Jul, 2022

Since the start of load shedding in April 2008, South Africa has been facing a steadily worsening energy crisis. Originally planned for maintenance, the ongoing energy crisis has pushed load shedding to Stage 6 levels in winter 2022. This is inhibiting business, further depreciating South Africa’s economy. 

With all this stress on both consumers and businesses, many have been considering switching to an alternative power source. 

Let’s clear up some questions about solar system installations and solar power generation. 

 

Is the cost of solar energy still inhibiting progress?

According to the World Economic Forum, the global average price of solar power has fallen more than 80% since 2010. In recent times, solar energy has experienced a sharper drop in price than any other alternative source of power.

We can credit this to more widespread efforts to increase the manufacturing scale of solar panels and other solar system components. Many governments have subsidised manufacturing and introduced tax incentives in the push towards alternative energy. We have seen a lot of milestones achieved in a short space of time, including the building of solar power plants at unprecedented sizes, and whole cities being powered by solar energy.

It is no wonder then, that we have been able to benefit from a wider selection of solar power products to choose from, at more affordable prices. 

While we still have a long way to go towards making solar power more affordable for the average household or small business in South Africa, we have definitely reached a point where the progress of development in solar energy is no longer being held back by the cost. 

 

How long is it before I see a return on my investment?

Before we dive into this, it is important to first discuss the solar payback period. A solar payback period refers to the amount of time it takes, from the moment it is purchased, for the system to break even. At this point, the amount paid for the system, including the installation costs, would then be equal to the total savings a household or business would make from not paying for grid electricity during that time period. 

We would also have to bear in mind any interest paid on loans taken out to cover the cost of the system, as well as any other fees or expenses incurred, so the payback period would be slightly longer when taking this into account. Another thing to consider is any tax deduction that would apply, since this would reduce your total cost.

The amount of savings made will also depend on the size and efficiency of your system. Maintaining the components to make sure they last as long as possible will also be important to consider. 

Taking all of this into account, a solar system will pay itself off in about 3-12 years. After the break even point, you can expect to see a return on your investment, as the benefits gained from your system will now be greater than the amount you paid. 

 

Key Questions about Solar Energy

  1. How reliable is solar energy?

Quality solar panels have very low failure rates. A recent study by the National Renewable Energy Laboratory (NREL) out of the US showed just a 0.05% failure rate per year of the panels evaluated in that study.

Their lifespan and low failure rate make them an incredibly reliable source of power. Many have found that a good set of solar panels can last even longer than 25 years, with some solar panels built in the 80s still being functional today. 

Keeping your solar panels clean and regularly checking them for issues could keep your panels in excellent condition for many more years to come. 

  1. How is the solar power generated stored?

In a solar system, the solar panels are connected to a controller, which is connected to a battery bank. The direct current generated by the system is stored in the batteries, which can vary from standard lead-acid deep cycle batteries, to gel or lithium-ion batteries

The batteries are connected to an inverter, which converts the direct current from the batteries to alternating current suitable for household or commercial power. 

  1. How long does a solar battery last?

Batteries have varying lifespans, depending on their quality and battery technology. The standard answer would be 5-15 years, but it is also important to take maintenance requirements into consideration. 

Generally, lead-acid deep cycle batteries can last up to 6 years with proper care and charging, depending on how frequently they are used. The same can be said for gel batteries, but these are a bit more forgiving when used frequently. 

A great quality, well-maintained lithium-ion solar battery can last up to 10 years. Of course, it is incredibly important to make sure that a good battery management system (BMS) is connected, which could extend the lifespan of your battery significantly. 

It is always important to remember that a healthy battery will last longer, and can even exceed its expected lifespan. 

  1. How do you calculate your peak power demand? 

When making the decision to install solar power, there are certain calculations that need to be done before purchasing any of the system’s components. Most people tend to go with a hybrid (solar/Eskom) solution, and will calculate their needs based on their requirements during power outages. 

One of the most important calculations is your peak power demand. This is the amount of power that will be drawn from the system during peak use. For example, this could be the power demand over a standard load shedding schedule, or however long you are expecting to be off Eskom’s power supply. 

Here is a simple formula to follow to calculate peak power demand: 

Peak Power Demand (W) = Rated power of appliance A (W) x Quantity + Rated power of appliance B (W) x Quantity + Rated power of appliance C (W) x Quantity + …

Peak Power Demand (Wh) = ( Rated power of appliance A (W) x Quantity + Rated power of appliance B (W) x Quantity + Rated power of appliance C (W) x Quantity + …) x No. of hours in use 

For example, if you are planning to run 6 light bulbs at 40W each, a large TV at 150W, a WiFi router at 10W, and a 500l refrigerator at 150W for a 2-hour load shedding period, this would be calculated as follows: 

( 6x40 + 1x150 + 1x10 + 1x150 ) x 2 hours = 550W x 2 hours = 1100 Wh

It also helps to buffer your calculations by adding some extra wattage to be safe. This would help you to decide on the size and number of units for your solar panels, batteries, and inverters. 

  1. Do I have enough space for a solar system to generate the power I need?

The amount of power you need will depend on the amount of electricity your household or business consumes. This can be very much related to the size of your premises and the number of occupants. 

Of course, a smaller space will also generally require less power. So, if your premises are compact and you do not require a lot of power, setting aside a small corner space should not be a problem. The solar panels will go on your roof, so the only components inside your house will be the battery bank and the inverter/s. 

There are also many space-saving solutions. Batteries made with solar and backup applications in mind, such as the i-G3N e-Stack or e-Wall range, can be stacked or mounted to a wall to save space. Inverters are also best mounted to a wall, so there will be very little floor space required. 

  1. Will my roof handle the weight of the solar energy panels?

Most roofs will have no problem taking the weight of a few solar panels. Crystalline panels can be quite heavy, so some roofs will not be able to handle their weight. Thin film cells might be a better alternative, even though they are less efficient. Solar panels made with aluminium will also be lighter than those made with steel. 

Ageing or structurally unsound roofs should always be seen to before putting up solar panels. It is best to have your premises checked by a contractor or inspector beforehand, as this will allow you to make any necessary changes early on. 

  1. What factors will affect the power generation of a solar system?

Knowing which factors will improve your system’s power generation capacity will help you optimise your design. Get the most out of your installation by considering the following: 

  1. Location of the solar system (Solar Irradiation/ weather conditions)

The amount of sun hitting your roof on a daily basis will drastically affect your power generation. Your solar system will be more effective during summer and on sunny days. 

  1. Plant layout

The way your panels are positioned and the components are connected will affect your system’s efficiency. A contractor can help you design the perfect layout for your building. There is also ample information available online on how to optimise your layout for maximum power generation. 

  1. Shading and roof orientation

Any trees or signage blocking your roof will reduce the amount of power your system is able to generate. 

Roof orientation, which refers to how much sun is able to hit your roof on a daily basis, is one of the main things to consider when designing your system. For solar panels to produce maximum output, they need access to as much sunlight as possible.

  1. Operations and maintenance on solar system parts

Maintaining your batteries, solar panels, and inverters is another critical part of ensuring that your system continues to generate power optimally. If you are not sure how to do this, it is helpful to check your product manual or ask your sales consultant for advice. 

  1. What to consider before installing a solar solution?

It is never a good idea to rush into an installation. The following factors should be thought out carefully before going ahead: 

  1. Solar System design

It will be very important to design your system before setting it up. Having diagrams and plans will help you to optimise the placement of your components relative to your building’s wiring and overall setup. This way, you can reduce your risk of unexpected issues in the future. 

  1. Energy requirements 

Calculating your energy load will allow you to be fully informed before making any decisions on your system’s components. This way, you can make sure that you are purchasing products that meet your energy requirements. 

  1. Correct technology 

The technology chosen for your system should reflect your needs. For example, certain battery technologies are best suited to more frequent use, while some would only be best used infrequently. The prevalence of power outages in your area will be a good indication of how often you will need to use alternative power sources. 

It is also important to check if the inverter you have in mind has PV (solar) compatibility, and if not, plan to purchase a PV inverter to use alongside your back-up inverters. There are a lot of other factors to consider when selecting solar technology, so putting in the research and consulting your contractor will go a long way in ensuring that you have everything you need. 

  1. The contracting company

Hiring a qualified, reputable contractor to help you design and install your system could prevent a lot of issues. Making sure that the company you have in mind is experienced and trustworthy will also take a lot of the burden off your shoulders. 

A qualified electrician is also essential, both before and during the installation process. Your building’s wiring will need to be properly assessed, and any wiring to be done should be completed by a trusted professional. 

  1. The quality and durability of the system’s components

Purchasing reputable brands with longer warranty periods will also reduce the chance of product failure down the line, and also ensure that you are protected in the rare case of something going wrong. 

  1. Product and Installation costs

Drawing up a budget prior to going ahead on your installation is fundamental. This allows you to select products that fit your budget. It will be important to include your solar installation costs, any building assessments, electrician costs, and any fees relating to municipalities or property management bodies that would apply to you. 

  1. Length of the project 

Based on the scale of your project, it will be necessary to find out whether you or someone you trust will be available to supervise your installation. If the installation is going to take some time, make sure to plan it long before any holidays or extended time away. 

 

 

When it comes to alternative power generation, solar power installations may initially seem quite costly, but they remain the only solution that returns the initial investment over time. 


To find out more about finding a solution that works for you, reach out to us at one of our branches, nationwide.