Ask Solar Mango

It was not long ago that solar trackers were considered an unnecessary luxury while setting up solar power plants. Although they brought about an increase in plant performance, developers weren’t willing to invest on the additional costs.

Solar Trackers are devices that come in conjunction with the mounting structures and help direct the panels in the direction the sun moves.

But as it stands today, trackers are gaining ground in India. Developers are becoming increasingly aware of the enhanced CUFs that tracker implementation could bring about.

Basically, there are 2 types of trackers: Single-axis and dual-axis trackers

As the name suggests, single-axis trackers rotate on one-axis, moving east to west, traversing the daily movement of the sun. On the other hand, dual-axis trackers perform both the daily as well as seasonal rotation of panels.

Single-axis trackers can bring about a CUF of 21%. In comparison with solar plants without trackers, this means an increase in performance of around 20-25%.

Dual-axis trackers does not make sense in the Southern states due to their proximity to the equator. But, in northern parts of India like Punjab, Rajasthan etc, which are located at a higher latitude, these could be beneficial. They can produce an increase in performance of up to 35%.

Since single-axis arrangement is preferred in India, the following discussion pretty much refers to single-axis.

Nowadays, most EPCs guarantee a power production of 19 lakh units with trackers in comparison to 15-16 lakh units without them. Trackers usually add an extra cost of 40 lakhs per MW to the capital cost plus an extra O&M cost of 2 lakhs per year.

What about the area required with trackers?

In fact, employment of trackers necessitates a greater land area to place the panels. Typically, a land area of 6-6.5 acres is required.

With this in mind, the designing the PV panel layout is of critical importance when trackers are employed. Due to the tilting of the trackers, the shadows from the panels fall over a greater area around it. If the shading from a panel from a particular panel fall on another panel, it could reduce the panel power output drastically. To account for this, the panels have to be appropriately spaced.

At Solar Mango, we have encountered cases where solar plant output reduced to the degree of even 9 lakhs per MW due to shading losses due to improper project implementation.

An interesting note in this context is the concept of backtracking. Most plants nowadays adopt the backtracking algorithm to avoid the shading effects which happen during mornings and late afternoons when the sun’s height is low.

An optimized backtracking strategy smoothens the daily production curves. For utility-scale projects affected by shading, solar tracker systems featuring backtracking algorithms can offer a sound strategy to accelerate ROI. It has been known to increase output by 5-10%.

A valid question among developers is the ROI when trackers are employed.

To explain this, let us assume that you plan to implement a 1 MW power plant. Consider the following parameters with and without trackers as given in the table below.

Assuming a PPA tariff of Rs 7/kWh, the extra revenue generated (inclusive of O&M costs) when trackers are employed is a whopping 4 Crores/MW for the entire lifetime. To put things in perspective, it is an added revenue of 4 Crores for an extra initial capital of 40 lakhs. Besides, the additional capital expense of Rs 40 lakhs usually pays back within 2 years owing to the extra generation.

When you look at such kind of numbers, it is clear that the decision to go for solar trackers is a no-brainer.

What about the extra maintenance required for trackers?

One aspect that many developers are concerned about, when it comes to use of trackers is the extra maintenance required. Many of them have asked us at Solar Mango whether the trackers could impose significant maintenance costs, and whether trackers could break down often, leading to disruption in the solar power plant operations and output.

These fears are unfounded, as long as you procure the tracker solution from a reputed company. While trackers indeed have moving parts and might hence some maintenance, note that the tracker movements are slow and gradual and hence are not subject to the same wear and tear that a fast running motor would, for instance.

Cutting a long story short, trackers do not require significant extra maintenance, and trackers supplied by reputed companies whether from India or international will be able to provide you with a significantly higher output at marginal increases in maintenance efforts and costs.

Summary

In sum, we feel that solar PV trackers have come of age for Indian solar power plants and it is time that Indian solar power plant developers benefitted from these.

In fact, Solar Mango Consulting Team has already assisted a client in making a decision on employment of trackers. In order to provide an extensive analysis on tracker implementation, Solar Mango’s dedicated technical  team offers a range of services.  Should you be interested in taking Solar Mango assistance for your MW scale solar power plant, please send a note to Ramya – ramya@solarmango.com