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.
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.
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 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.
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).
The main electricity supply provider.
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.