Combat shading issues and maximise solar production

Combat shading issues and maximise solar production

Over the recent years, the discovery of solar energy and the ability to convert this abundant energy resource into usable power has led to a tremendous decrease in the greenhouse emissions across Australia. With the developments made in solar technology, the production and manufacturing costs for solar panels have significantly decreased over the years making the installation of solar panels extremely affordable for a larger population. Government introduced incentives introduced across Australia play a vital role in encouraging a larger population in going solar.

It is necessary to consider the location and positioning of the solar panels on your roof when deciding to go solar. Since solar panels require direct sunlight in order to function efficiently, when there are issues like shading on the roof, potential solar buyers would often get discouraged to consider solar as a viable alternative option to traditional sources of energy. However, with advancements made in the field of solar technology, with the help of solar technology like microinverters and DC optimisers, even roofs with shade can be great candidates for an efficiently functioning solar power system.

A shaded solar system without optimisers, the solar inverter still does its best to harvest as much energy as possible from the solar array. For any panels in shade, their internal bypass diodes may be ‘on’, bypassing the part of the panel that is in shade. This is done to protect the shaded panel from excessive heating, but it also improves the shaded panel’s output and can reduce the shading’s effect on the rest of the array. Panels usually have three strings of cells and three diodes, so that partial shading doesn’t cause the entire panel to stop producing. However, each part of a panel that is bypassed produces no voltage, so a heavily shaded array can drop below the input voltage allowed by the inverter, causing the system to stop feeding power to the grid. Also, sometimes there isn’t enough shade on a panel to cause any of the diodes to activate, so the entire array is limited to the reduced current that can flow through the shaded panel. This is where optimisers come in.

The angle that solar panels are installed at also plays a crucial role in determining the solar production of your rooftop PV System. The orientation and inclination of the solar panels is one of the most important factors to consider when installing a rooftop solar power system because your solar panels will only be able to produce power when the sun is directly perpendicular to them. During the winter in the northern hemisphere, for example, the sun is low in relation to the horizon. In this case, for the solar panels to get their best performance, a steep angle of 60° is best. During the spring the best angle is 45°, and during the summer when the sun is high in the sky, it’s best to have a low tilt at 20°. Similarly, if the roof is flat for the location where you want to install a solar power system, or has a pitch that is less than 10 degrees, tilt frames are recommended by skilled solar installers to ensure that you get the maximum production out of your solar power system.

To best optimize the production of solar panels, do not underestimate the importance of their orientation and inclination! However, it’s not always about producing a maximum amount of energy; it is also necessary to take into consideration your consumption needs. For instance, if you are self-consuming your electricity rather than selling it back to the grid, the optimal orientation is not necessarily the same.

If you mount the solar panels flat, the biggest problem is not reduced energy yield compared to north-facing solar panels. The biggest problem is rain pooling on those flat solar panels which consequently means that they won’t self-clean in the rain, making grime build up over time which will eventually affect your solar production. The built up grime on the solar panels compromise your energy yield and potentially slowly eat the seal between the aluminium frame and the glass.

In the case of “self-consumption” for the PV production, it can make sense to orient the panels east/west rather than south-facing. East-facing panels will produce more energy in the morning, west-facing more energy in the late-afternoon. With respect to energy autonomy, the goal is not to produce the maximum but what is needed.

The perfect roof to install solar panels on in Australia to maximise the solar energy generated over a year is a large roof, facing north and inclined at an angle close to the location’s latitude.

Solar Panels mounted parallel to this perfect roof will be optimised for annual energy yield, and in most parts of Australia, should seldom need cleaning. Thanks to their angle, rain will slide off, cleaning the solar panels as it goes.

A minimum tilt of 10° is recommended to take advantage of self-cleaning during rain events. Where panels are installed at a tilt angle less than 10°, it is advised to the customer about the need for more frequent cleaning of the modules, and this should be included in the recommended maintenance schedule.

Some people are happy to live with flat panels and either accept the reduced energy from grime build-up or clean them regularly.

But if you don’t want flat panels on a flat roof, the obvious option is to install them on tilt frames. And the traditional thinking on a residential roof is that if you are going to the effort and expense of tilt frames, you may as well tilt the solar panels to the north and at the optimum angle for the location – approximately the latitude.

This logic makes sense in the bygone era of expensive solar panels so as much energy as possible can be generated and used up from each solar panel.

But now solar panels are so cheap, the homeowner’s priority is more often squeezing as much energy as possible from the roof area. That can often lead to a different system design than the traditional approach of maximising yield from each module.

Contact SunMate Solar today for a free quote and guidance on the proper rooftop layout plan specifically designed for your roof to maximise your solar production.

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