TRACKING THE SUN

Solar power has been identified as one of the emerging sectors of future growth. The solar energy is abundant in our country, and India gets normally 300 days of solar radiation in a year. The inexhaustible sun power not only augments energy generation, but also contributes towards the improvement of environment, energy conservation, and additional employment.

But problem associated with the use of solar energy is that its availability varies widely with time. The variation in sun occurs daily because of the day-night cycle and depends on seasons because of the Earth’s orbit around the Sun. The solar power generation gets limited to day light.

To avoid such limitations, a means of tracking the sun was required and a new innovative technology- solar tracking system was brought into existence.

This technological concept allows more energy to be produced because the use of trackers allows solar arrays to catch up with sun every minute, every hour.

Solar trackers are rising in popularity, but not everyone understands the complete benefits of this system. Solar panel tracking solution is an advanced tech-nology for mounting photovoltaic panels. Stationary mounts, which hold panels in a fixed position, can have their productivity compromised when sun passes to a less-than-optimal angle. Compensating for this, solar trackers automatically move to track the progress of the sun across the sky, thereby maximizing output. This is a far more cost effective solution than purchasing additional solar panels. It has been estimated that the output from solar panels can be increased by 20-30 percent by utilizing a single axis tracking system instead of a stationary array.

One way to make the solar panels more effective is by adding the ability to track sun as it moves across the sky. Solar Tracker is a device which follows the movement of sun as it rotates from east to west every day, using the light sensors interfaced to motors used for rotation, through a microcontroller, to have maximum solar radiation incident on the solar panel. The motors can be used to move panels either along ONE or TWO axes.

Using Solar Trackers increases the amo-unt of solar energy which is received by solar energy collector and improves the energy output of heat/electricity. Solar Trackers can increase the output of solar panels by 20-30%, which improves the economics of solar panel project.

Solar Trackers are mostly suitable for use in ground mounted PV solar utility scales with capacity more than 1 MW. Solar Trackers are especially useful in case of places, where the solar insolation is high and the efficiency of solar panels being used is high. From practically nothing two-three years ago, India now has more than 1000 MW of solar power plants that have been added with trackers. It might be the small fraction of 8GWof solar installed in the country now, but the use of trackers to catch the solar radiation in our country has become norm rather than exception.

Product Insights

The use of trackers adds to the efficiency of system, reducing size and cost per kWh for solar power plant.

The solar tracker market has been segmented on available technology, product types, use and key regions. Solar PV, CPV and CSP are major tech-nology segments of the solar tracker market. Flat-panel photovoltaic (PV), Concentrated Photovoltaic (CPV) and Concentrated Solar Thermal (CSP) are technologies where solar trackers are implemented. Solar trackers have distinctive functionalities in all application such as orienting optics in CPV and CSP systems, minimizing the angle of incidence among the PV panel and incoming sunlight in PV applications. In terms of technology, solar PV dominated the market followed by CSP and CPV in 2014-15. This segment accounted for over 40-45% of the global solar trackers installed capacity.

There are single- axis and double-axis solar trackers. The single-axis solar trackers deliver a performance gain of 25-35%; while using double-axis solar trackers, performance goes up additionally 5-15%. Single axis trackers track’s the sun from east to west on a single pivot point, while Dual axis trackers trail east to west and tilt for north to south tracking.

Back in 2014, single axis trackers were the largest segment of the market owing to their low cost. Surge in the use of single axis particularly for commercial and residential is likely to have a positive impact on the market. However, single-axis technology tends to lose share as major companies worldwide started giving preference to dual axis owing to latter’s efficiency and accuracy.

The use of single axis trackers does maximize the potential output but also bring forth higher OPEX (Operating Expenditure) and CAPEX (Capital Expend-iture). On the other hand, dual axis trackers are envisioned to be the Fastest Growing Technology in industry over the forecast period on account of improved efficiency.

Market for Dual axis tracker is expected to grow with Compound Annual Growth Rate (CAGR) of 14.5% over the forecast period to reach an installed capacity of 9684.1 MW by the year 2022 worldwide. In light of higher costs and land space, dual-axis technology found usage mostly in developed regions of Europe and North America, and will witness increased acceptability in emerging economy like India in next few years.

Single Axis Trackers

Single axis trackers have one degree of freedom that acts as an axis of rotation. The axis of rotation of single axis trackers is typically aligned along a true North meridian. It is possible to align them in any cardinal direction with advanced tracking algorithms. There are several common implementations of single axis trackers. These include Horizontal Single Axis Trackers (HSAT), Vertical Single Axis Trackers (VSAT), Tilted Single Axis Trackers (TSAT) and Polar Aligned Single Axis Trackers (PSAT).
Single Axis Trackers are used to minimize the angle of incidence between incoming sunlight and a solar panel with help of sensor. This system tracks the sun only from east to west direction.

Dual Axis Solar Tracker
Dual axis trackers have two degrees of freedom that act as axes of rotation. These axes are typically normal to one another. There are several common implementations of dual axis trackers. These are classified by the orientation of their primary axes with respect to the ground. Two common implementations are Tip-tilt Dual Axis Trackers (TTDAT) and Azimuth-altitude Dual Axis Trackers (AADAT). Dual axis trackers are typically used in locations with very high gove-rnment Feed-in-Tariffs.

Dual axis tracking system uses the solar panel to track the sun from east to west and north to south. It can rotate simultaneously in horizontal & vertical directions and are able to point at the sun at all times. Dual axis trackers follow the sun both East to West and North to South for added power output- approx. 30 to 40% gains.

Classification of Solar Tracker Drives

Solar tracker drives, can be categorized into three main technologies depending on the type of drive and sensing or positioning system that they incorporate:

Active Trackers

These use motors and gear trains to direct the tracker as commanded by a controller, responding to solar direction. Since motors consume energy, one wants to use them only as necessary.

Passive Trackers

These trackers use a low boiling point compressed gas fluid that is driven to one side or the other (by solar heat creating gas pressure) to cause the tracker to move in response to an imbalance. As this is a non-precision orientation, it is unsuitable for certain types of concentrating PV collectors, but works fine for common PV panel types.

Open Loop Trackers

These use no sensing but instead determine the position of sun through prerecorded data for a particular use. It uses computer controlled algorithms or simple timing systems to determine the position of sun.

Main Components of Solar Trackers

• Tracker Mount
• Drives
• Sensor and Sensor Controllers
• Motor and Motor Controllers
• Tracker Solving Algorithm

Benefits of Solar Trackers

• Trackers generate more electricity than their stationary counterparts due to increased direct exposure to solar rays. This increase can be as much as 10 to 25% depending on the geographic location of the tracking system.

• There are many different kinds of solar trackers, such as single-axis and dual-axis trackers, all of which can be the perfect fit for a unique jobsite. Installation size, local weather, degree of latitude and electrical requirements are all important considerations that can influence the type of solar tracker best suited for a specific solar installation.
• Solar trackers generate more electricity in roughly the same amount of space needed for fixed tilt systems, making them ideal for optimizing land usage.
• In certain regions some utilities offer Time of Use (TOU) rate plans for solar power, which means the utility will pur-chase the power generated during the time of the day when sun radiation is at a higher rate. In this case, it is beneficial to generate a greater amount of electricity during the daylight. Using a tracking system helps maximize the energy gains during these peak time periods.

Chasing the Helios

Tracking is mostly apt for large industrial and commercial solar application, and less recommended for residential rooftop systems. The residential rooftops, where tracking systems are installed, they have to be offset from roof in order to allow for the complete and uninterrupted movement of the panels. This in turn might increase wind load and require an expensive racking system. Also, there are some cost, space consumption and architectural considerations that restrict the use of trackers in residential and rooftop.

According to a study conducted by Grand View Research (GVR), the non-utility sector accounted for less than 15 percent of the global installations in 2015 and is expected to witness lowest CAGR of 14.7% from 2015 to 2022.
Even on large-scale projects, solar trac-kers necessitate the use of a larger area compared to fixed racks because movement of panels might create shadows on other panels if there is no appropriately calculated space made.

The use of tracking system in solar setup has been awesome. The effort made by major tracking companies in India and worldwide to supply massive demand for utility-scale installation has turned out to be considerably good in the past few years. The global demand curve for solar trackers has been heading straight up, and the result can be seen in India too.
Recently, SunLink and Ganges Inter-nationale have entered into a joint venture to speed up the solar deployment in rapidly growing Indian market. As part of a SunLink-White House commitment to deploy 1.4GW of solar in India over the next five years, SunLink has partnered with Ganges to support India’s 100GW National Solar Mission. Under the agreement, Ganges will manufacture, install and provide O&M support for SunLink TechTrack single-axis trackers in India. SunLink will provide not only its proven technology but also PowerCare engineering services and VERTEX
software platform to Ganges and its customers.

The United States tracker manufacture, NEXTracker has delivered its award winning PV technology tracking system to Adani Power’s 150MW solar project in the state of Punjab. Such collaborations and projects does indicate that tracker industry is gaining a strong momentum in India, significantly enhancing the financial value of PV solar as the most important energy generation asset.

Vikram Solar also launched its Helitrac, which is an advanced solar tracker equi-pped with IP65 robust weather proof mechanism and multimode intelligent operations. Helitrac is capable of chan-ging its orientation throughout the day to follow sun’s path to maximize PV efficiencies.

In recent years, the deployment of trackers has often been stimulated by steady digression of the government incentives such as subsidies and feed-in tariffs (FiT). Thus, as payments and cost for solar energy have pared down, the project developers have taken initiative to experiment with trackers to maximize output.

India is poised for intensive ground mount solar deployment over the next decade according to a recent report by Deutche Bank Market Research, with 100-fold solar industry growth over the last five years. As a more modest figure, it is estimated that ground mount solar installations with solar trackers will hopefully reach 3GW to 4GW by 2020, or 25% of total installed ground mount installations.

A recent research suggests that Asia Pacific solar tracker market is expected to witness significant gains by 2022 in light of growing awareness towards the importance of trackers. In addition, it is expected to witness high growth on account of increasing electricity demand in emerging economies of India and China. Europe and North America together dominated the global solar tracker industry on account of greater installed capacities.

Moreover, incentive schemes under the various government policies in India, coupled with decreased rates are expected to drive demand for trackers over the forecast period. India is expected to witness considerable growth over the forecast period, in light of growing demand for solar energy generation.

A study conducted by Grand View Research states that Global solar tracker market share was characterized by moderate consolidation on account of top companies accounting for over 40% of the total installed capacity in 2014. Major companies are expected to shift manufacturing base to developing countries including India and China on account of the low cost of production and low labor costs. Key manufacturers are engaged in R&D to gain competitive advantage.

When trackers were first introduced on to the market, they were usually fairly bulky and unreliable. Many of the trackers installed in Europe during the Feed-in-Tariffs (FiT) boom suffered from major reliability issues, sometimes with repeated incidences of failure.

However, with time, experiments and new technologies, trackers have become far more innovative. For example, using GPS to realigning trackers automatically is a sign of latest innovation in tracking system. Companies such as NEXTracker has incorporated control systems into their trackers which monitor the angle of each row of solar panels in real time and report back on tracking accuracy in order to keep panels facing directly into the sun all the time. The company’s NX Horizon product is a self-powered tracker (SPT) which has a self-contained motor, enabling it to be deployed on each row of panels which in turn eliminates wiring and trenching as well as saving power.

AllEarth Renewables’ Dual-axis Solar Tracker seems like an amazing new development in the solar segemnt. AllEarth’s tracker uses GPS and wireless technology to track sun’s arc in sky throughout the day. The result? Soaking up 45% more energy than traditional rooftop solar. Over 4k trackers have already been installed, and AllEarth is poised to take the rest of the solar market by storm. The trackers are designed for residential, commercial and industrial operations, along with small and large utility-scale installations.

Recently at SNEC 2016, Scorpius Trackers, an Indian company that provides single-axis solar tracking solution, showcased its latest tracking system that can function for up to 25 years without any main-tenance. The company has provided about 70MW of solar trackers last year, and aims to deliver 500MW this year; with 2GW as it future target. But des-pite choosing to put its foot forward in dual-axis technology, the Indian tracker manufacturer experimented with single-axis. Reason being- the structures of dual-axis solar trackers are more compl-icated and mounting-systems are heavier. Dual-axis tracking systems are also more expensive and susceptible to damage.

Nevertheless, innovative developments in solar tracking are making it much more attractive, especially in areas of high solar radiation. Maintenance costs are also beginning to fall as the technology improves. More projects are now using trackers and the market is thriving. It significantly increases the turnover of large plants resulting in an augmented use of the tracking systems in utility scale installations. The market is expected to witness significant growth on account of the momentously rising PV installations across the world. The PV market grew by 50 GW last year while total capacity has reached at least 256 GW around the globe. In fact, current predictions point that Global Solar Tracker market size will reach USD 6.83 billion by 2022. And that’s fairly impressive.