How to Choose the Best-Suited Solar PV System
When choosing the best-suited solar system, the power requirements, available space on the roof for mounting purposes, as well as the available budget are all taken into consideration. The quality of the solar panels and solar inverter will also be a determining factor in the price. Therefore, this needs to be taken into consideration so that a true comparison can be made, much like comparing apples with apples.
In making an informed and educated decision, you will be benefiting by selecting the most cost- effective and beneficial PV solar system for your requirements.
IMPORTANT FACTORS TO ACHIEVE THE MAXIMUM YIELD FROM YOUR SOLAR PV SYSTEM
- The amount of power the solar PV system generates
- The performance of the system
- Energy of incoming light
- Target yield
- Performance ratio
- Energy output per area
- Energy per rated power
- Energy losses (pre-photovoltaic losses, module, thermal losses and system losses)
- Cable thickness
- Temperature
- Shading
- Charge Controller and solar cells IV characteristics
- Inverter efficiency
- Battery efficiency
BASIC SOLAR PV SYSTEM COMPONENTS
Solar Panels
Photovoltaic (PV) solar panels use the rays of the sun to convert into electricity. Two or more panels, depending on the system requirements, are connected either in parallel or in series and together these panels absorb the rays from the sun and generate the electricity. The bank of panels is commonly known as the solar array.
DC Isolator
The isolator is a breaker that can disconnect the solar panels (array) from the inverter. This normally happens when maintenance is done on the system or when some inverters have built-in DC isolators.
Inverter
The main function of the inverter is to convert the DC electricity (direct current) generated by the solar panels to AC electricity (alternating current) that is needed for the utility grid and the form of electricity that almost all appliances require in order to operate.
Another function
Another function of the inverter is to provide the link between the panels and the main utility grid so that should either the solar panel system or the utility grid have a failure, the inverter would protect the system.
Generation Meter
This meter counts the amount of electricity units created by the solar PV system and is necessary for instances where excess PV electricity generated is fed back into the main utility grid (only applicable in certain areas and with the consent of the relevant municipality).
AC Isolator
A circuit breaker that is included to enable the disconnection of the solar PV electricity supply from the utility grid supplying the premises. This is primarily used when maintenance needs to be done on the utility grid.
Fuse Board
The board where the solar PV system is connected to the main utility grid supplying the premises.
Current Supply Meter
Should you require more electricity than your solar PV system generates, you will need to draw electricity from the main utility grid (especially at night). The electricity that is drawn from the utility grid will be billed for as normal.
The Utility Grid
The main electricity supply provider.
Use of Electricity
There will be instances that you will be drawing from the solar PV electricity and others where it will be necessary to draw from the main utility supply, but depending on the size of your system and the load determined, this will only be noticeable should you require full use of all appliances, lights, etc. as the solar PV system will only be able to power the determined load.
FREQUENTLY ASKED QUESTIONS REGARDING SOLAR PV SYSTEMS
How does a solar PV system work?
The solar photovoltaic (PV) panel absorbs the rays of the sun in the daytime and draws the most power when they are in direct sunlight. Panels do still absorb the rays on overcast days, but not as efficiently as on sunny days.
The power generated from the panels is converted from direct current (DC) to alternating current (AC) via an inverter so that it is safe to power your premises.
Should the solar PV panels be mounted on the roof or on a structure on the ground?
The answer to this question is that it is totally dependent on the requirements and wishes of the individual client as to where they want the panels mounted. Roof-mounted systems are usually less expensive as the structure required is not as large. Roof-mounted systems are also normally less visible from ground level and this may suit the client.
Ground-mounted systems would normally require a large structure, but the advantage with these structures and mountings is that you are often able to have the structure made in such a way that it is able to tilt towards the sun at any given time, which will optimise the panel’s power production.
Should future expansion plans for the premises be taken into account?
It is advisable that, should you be planning on expanding your premises in the future, you should consider this when advising your consultant of your requirements as these expansions will need to be factored into the design and space available for the mounting structure for the panels as well as the size of the inverter and battery bank if necessary.
Should I choose to have a roof-mounted system, how much weight will this put on the roof?
Depending on the roof-size available for the mounting structure and panels, as well as the size of the system required, typically a large system would weigh approximately 22-25kgs per panel (including the mounting structure and hooks and for a 250 / 255W solar panel). The approximate panel weight alone for this size of panel is 20kgs.
The roof is typically designed to hold two to three times that amount of ‘dead weight’, depending on the size of the roof.
How long do PV solar panels last?
The manufacturer’s warranties for Tier 1 Grade A panels are generally 25 years, with a 1% performance degradation year-on-year and are warranted to produce 80% of their rated output in year 20. There is also generally a 10-year workmanship warranty on the panels.
How quickly will a solar electric system pay back its installation costs?
Depending on the size of the system, it could take between five and eight years for the system to pay for itself. This means that after the initial pay-off period the system will save you money for the rest of its life.
What is the difference between System Power Output and System Energy Production?
System Power Output – The alternating current (AC) output of the solar panel system is measured in Watts (W) and kilowatts (kW) is normally displayed on the inverter screen or monitoring controller. It is instantly measured by the direct current (DC) output from the solar panels, the efficiency of the inverter and any system losses.
System Energy Production – The alternating current (AC) energy production is measured in kilowatt hours (kWh) and is measured over long periods of time. This production is also normally displayed on the inverter screen or monitoring controller and can be compared to the usage as seen on the premise’s electricity account.
What happens on rainy / cloudy days?
Should the system be of a grid-tied nature, the inverter will switch over to the main utility grid in order to provide an uninterrupted power supply to the premises.
Should the system be one of an off-grid nature, the power generated and stored in the battery bank will provide the power required until such time as the weather is more favourable and able to generate solar power again. This type of system is more susceptible to down-time as the weather can’t be controlled.
Is it necessary to have batteries with a solar PV system?
If you are looking for an off-grid solar PV system then it is a requirement to have a battery bank; the size of which is totally dependent on your requirements and the size of the entire system.
Should your system be purely for a power back-up solution in the event that the main utility grid fails or is interrupted, then batteries will also be required as they to be charged in the event of use.
Should the need arise, can my roof be repaired after the solar panels have been installed?
Reputable roofing companies are able to attend to roofing repairs without any complications as the panels are mounted in such a way that, should it be necessary, they can be removed and then replaced once the repair work has been completed.
What maintenance is required for the solar PV panels?
Solar PV panels have no moving parts and require no maintenance apart from cleaning, which can be done with a hose pipe, and preferably four times a year. Some clients prefer to use a high-pressure hose should the solar PV array be easily accessible. It is recommended that the system be checked by a qualified installer every 1-2 years to ensure that all connections are correct and should any extra connections be required, the installer will be able to do this for you.
What happens if there is a power outage?
More often than not, solar PV systems are linked to the main utility grid, which means that should there be a power outage, the solar PV system shall activate and power the required appliances or premises accordingly.
Will components on the solar PV panels rust?
All the components of the panels and mounting structures are designed for outdoor use and therefore made with the relevant materials.
How can the power benefits of the solar PV system be maximised?
The panel array should be installed on a north-facing roof area and angled at 30° to maximise the power generated. Any shade that falls on the specific area where the panels are to be installed should be eliminated, for example, trees that shade the area should be cut to allow the panels to be fully exposed to light. Should the roof not have a pitch of 30°, a mounting structure is constructed to enable the panels to be elevated to that pitch.
Can a solar PV system add value to a property?
According to international surveys over the last 5 years, energy efficiency and ‘green’ properties are a major draw card for potential buyers. It has been noted that potential buyers are prepared to pay more for premises that are energy efficient than those which are not.
READ MORE ABOUT PHOTOVOLTAIC SYSTEMS
Photovoltaic Systems are nothing new in South Africa. With our abundance of sun energy, it was only a matter of time before companies and individuals alike began to look to ways that would let them convert that renewable sunlight into electricity to power homes and businesses all across the nation. Solar electricity is the way of the future and now you can also harness the energy of the sun to provide power to you need it.
Photovoltaic Systems are for sale to both companies and the public these days and before you decide to buy a system of your own, you should make sure that you have the right knowledge before you settle on a product.
Simply put, a Photovoltaic System is a system designed to absorb solar power and convert it into safe usable energy. The system includes everything necessary to make the conversion, including solar panels, a solar inverter and all of the cabling. The energy is converted from DC current to a safe AC current which then works in the same way as electricity supplied from the national power grid. A solar PV power system is the very best way that you can use solar energy on a large scale.
The style of Photovoltaic Systems differs depending on your needs and depending on where you are buying your system from. For instance, the most popular system is that which is mounted onto a roof while building integrated systems or standalone systems are also available. The versatility of the design of PV systems gives you many options when you are looking for the system that will be best suited to your needs.
Many think that you have to be dedicated to going green in order to invest in such a system, but actually anyone who considers investing and installing in a solar PV system is making a lifelong investment towards saving money while enjoying the added benefit of knowing that you are doing your part to save the planet.
The best way to decide whether or not to buy a PV power system is to have a careful look at the benefits that you will be experiencing as well as any disadvantages that might come along with the package.
The advantages of Photovoltaic Systems include:
Solar energy is free to use.
All of the electricity generated from a PV system is environmentally safe.
Solar power can be harnessed from pretty much anywhere as long as there is sunlight.
This energy is renewable; you can use it time and again without it running out.
The operating costs involved with a solar PV system is exceptionally low.
The costs involved when buying a solar PV system is slowly reducing, making it more affordable for everyone.
Photovoltaic Systems operate silently so you will never be bothered by noise.
Power systems such as these can be attached to just about any structure.
Maintenance for the PV power system is going to be next to nothing.
As with all systems, there are going to be a few disadvantages to consider when you are looking to buy a solar system. Here are a few to keep in mind:
Cloudy days and rainy weather might have an effect on the system. But the effects are minimised when a solar battery is being used to store the power that has been generated.
The initial setup might be slightly expensive, although the prices of PV power systems have come down drastically in recent years.
These systems are fragile and can be damaged, so you will need to keep an eye on it.
Photovoltaic Systems are guaranteed to change the way that you look at electricity while the system is sure to also change the way that you access to power.
There are a few power systems that you can choose from, here is a breakdown of the 2 most popular solar power systems currently on the market:
Off Grid PV System – with this system you will be completely off the grid, relying 100% on power generated by the sun. This power system will store any unused energy and allow you to access it when need be. The unused energy is stored in special solar batteries.
Tied Grid PV System – Not completely independent of the national electricity grid, this system generates enough power for its purpose and it is also able to store power in batteries. But unlike the Off Grid System, this system can also feed any unused power back into the national grid. This system will be beneficial to your community without costing you anything extra.
The scale of Photovoltaic Systems
One of the factors that makes PV systems a great option for generating power is that they come designed in different scales. What does this mean? Well, depending on the amount of electricity you need to generate, and the scale on which you will be using the energy produced, you have the option of choosing the right scale.
The scales generally consist of 3 sizes, or 3 systems: Utility, Rooftop, and Building integrated.
The utility scale systems are best described as solar farms, with panels and the accompanying components spread out over a wide area. These PV systems are designed to provide a massive amount of energy and a massive return on investment.
The rooftop system is most commonly found on homes, but they have also been used to power satellites, solar cars, and street lights. By 2013, around 60% of solar systems were rooftop systems. If you are looking to fit your home with a PV system, then this is likely to be the one that you go with.
The building-integrated system can consist of a wall of solar panels attached to a system capable of generating enough power to keep an entire building supplied with electricity.
Save money, save the planet and go green with the Photovoltaic System of your choice. Call us today or send us an email to find out more or to buy a PV system of your own.