Even though solar trackers appeared in the market nearly two decades ago, the utility scale solar market for tracker in India is still at its nascent stage owing to customer perception on need for extra land and higher grading.
However, with new innovations, and with entry of new tracker companies in the market, some of these perceptions and disadvantage of tracker have been eliminated. As timelines for solar plant development are crunching, most developers opting for Tracker want minimum grading at site. Thus, managing undulations with tracker has become the critical feature for developers. A traditional building block tracker which has a shaft running throughout the plant connecting almost 20-30 rows does have this disadvantage of requiring a flat land. The use of Single Axis trackers which doesn’t have any coupling in E-W direction helps overcome this disadvantage.
MSAT -100, Mahindra Susten Azimuth Tracker is a testament to engineering improvisation and simplicityfor managing site undulations. With MSAT-100 900mm slope for 60m span in North-South direction and 300mm slope can be managed in East-West direction for 5m pitch.The undulations can be managed through various means, some of the ideas already implemented on site are listed below:
Combination of RCC foundations & Piling:
Combination of RCC foundations & Piling: This solution is conventional way of managing ground level tolerances up to 1 m. Through engineering design, a layout is provided which has a combination of posts embedded in RCC foundation and in plain concrete foundation. The muff of RCC foundation is raised to ensure that the top of the foundation remains the same.
The solution has been implemented at CleanSolar Site in Telangana. As can be seen in the contour drawing, the land is extremely undulated., however without any grading work, 7.5 MW tracker was installed through acombination of RCC foundations& Piling.
Varying Stub Length:
RCC foundations could be a costly prospoition and requires more time for land parcels with high undulations. Varying stub length from 2.7m to 3.5 m is another way to handle these undulations. As there is no E-W coupling between the rows, this solution becomes extremely viable for highly undulated sites. The stubs are color coded and all the foundations pints marked clearly in the layout to ensure ease of installation at site.
Use of Couplers:
Usage of couplers below ground is one of the other solutions for management of undulations on land. With this solution, even if the below ground level depth of the post is less than required, couplers ensure that the above ground level length remains the same, so that even with undulations the torque tube is at a symmetrical position. The additional advantage of Coupler over varying stub length is ease of installtion and lower costs.
The right mix of any/all of the three solutions ensure tracker can be installed at almost any site with ease, without need for grading. Also, with reliable technologies coming in, Solar tracker is now making sense more than ever. Mahindra Susten with its alternate and simple approaches ensure reliability and bankability of its products to ensure better rigidity and ease of installation.