Solar panels that revolve around the sun

One of the challenges facing solar energy is how to optimise the production process to get better results. Even though in recent years the efficiency figures for solar panels have improved greatly, they are still behind others like wind. Whilst wind turbines have an efficiency of between 40% and 50%, the average for solar panels is only almost 20%.

So it should come as no surprise that all of the industry's efforts with regard to innovation concentrate on how to optimise solar panels to improve production and make it more sustainable, and one of the most recent solutions is solar trackers.

Solar trackers: Innovation to further optimise solar energy

The angle at which the sun's rays strike the surface is one of the key factors in the production of solar energy and one of the reasons for the low efficiency of solar panels. The more perpendicular the angle, the more energy the panel produces, but as the Earth moves, the rays' angle of incidence is not always ideal.

Faced with this problem, solar trackers emerge as a solution. These are mobile structures that fix the solar panel to the ground, enabling the angle at which the panels receive solar radiation to be regulated. This improves electricity production by ensuring that the panel is in the optimal position at all times.

Solar trackers have certain advantages and disadvantages it is important to take into account before investing in this technology:

Advantages

• There is no doubt that these installations are very profitable, because they may last for about 30 years, but they pay for themselves well before that: In between five and ten years.
• Single-axis solar panels with tracking are between 25% and 35% more efficient and this increases by a further 10% if the tracking is on two axes.
• The solar tracking system would make it possible to install panels in high-latitude areas, where the position of the sun changes enormously from one season to the next.

Disadvantages

• The main disadvantage for this solution is the high cost of installation and maintenance, as they require more care than fixed solar panels.
• The added weight of social trackers may prevent robbery but it means that it is not feasible to install them on a roof. In this regard, even though they may be purchased individually, they are not usual in domestic installations.

But how do solar trackers work?

José Manuel Suárez, industrial engineer and Chief Executive Officer at IMEnergy, provided a detailed explanation: "Depending on their location, the structures of the trackers are programmed using an algorithm that undertakes the solar tracking with the aim of keeping the photovoltaic modules as perpendicular as possible to the sun's rays and to maximise the capture of solar energy they point east in the morning and west in the evening."

There are a number of criteria for classifying solar trackers:

In accordance with the number of axes:

• One axis (usually north-south): The solar panel moves on a single axis from east to west following the path of the sun. Because this is a simpler formula it costs less, although the movement is less precise.
• Two axes: This enables movement in all directions to optimise energy production in all seasons of the year. There is also an additional added advantage, and that is that these panels are difficult to steal.

In accordance with the engine systems:

• The most common system is electric
• Hydraulic energy is generally used for large trackers
• Gravity-driven, so they do not need electricity, but a certain amount of control is lost

In accordance with how they are controlled:

• Manually Lower costs but less accurate
• Automatically Microprocessors use sensors or an astronomical data programme to determine the position of the sun

Increasingly robust solar panels

One of the companies leading the work to make photovoltaic solar energy an increasingly accessible option is Soltec, which not only manufactures solar trackers, but also panels with innovative technology that protects them from inclement weather. This Spanish company is one of the main companies supplying solar trackers and is a collaborator of Enel Green Power Spain.

One of its latest products is the SF series, extremely robust as a result of unique methodologies. For example, it includes Dy-Wind technology that as a result of a series of improvements, updates the standard designs for wind energy which are insufficient for solar trackers. The changes include strengthening the tracker's rotation bushings to achieve a more robust structure to combat the wind; and increasing the rigidity and robustness of the tubes, as well as the turn actioning.

Are solar trackers for self-consumption worth while?

The idea of installing solar panels with trackers can be very attractive to optimise energy production and improve performance. But before installing them, the location and weight should be taken into account.

The operation of solar panels is based on being installed on a flat surface so they can move and follow the sun. So they cannot be installed on a sloping roof, which is what usually happens. A flat roof or garden could work, providing there is enough space for them to be able to move correctly and capture the sun's rays.

And as we already mentioned, solar trackers make the panels much heavier than standard panels. Before buying them, it is important to check that the area where they are going to be located can support their weight.