Solar Seasonal Tilt-A Quick Analysis

PV Solar Plants are of 3 types principally – i) Fixed Tilt Plant ii) Tracker based plants (most common are with Single Axis trackers) iii) Seasonal Tilt Plants.

Fixed Tilt Plants are installed at a fixed tilt angle, mostly linked to the latitude of the place and facing south (for plants installed in the northern hemisphere). Single Axis tracker plants are installed with trackers aiding the movement of the Solar panels, that face East as the day starts and progressively moves towards the west as the day ends. Trackers are expected to boost energy generation by a conservative ~15% against Fixed Tilt Plants.

Many a time there is a discussion on how much seasonal tilt of Solar Modules offers as generation improvement against a fixed tilt PV Plant. As seasons change, the benefits also change. On an average there is a 5-6% increase in generation /year, with certain seasons offering an improvement of >10% with the right element of seasonal tilt.

Usually Developers opt for 3 tilt angles for the solar panels in a year (within the tropics in the northern hemisphere) –:  typically, 3 to 5 degrees from April to June, 17 to 20 degrees from July to September and 27 to 35 degrees from October to March depending on the latitude of the site.

It has been assessed that the seasonal tilt benefit during the winter season is minimal; since the tilt angle remains the same, say at 35 degrees for 6 months with no further angle changes planned, there are less chances of accrual of more benefits than in summer months.

The seasonal tilt angles to be used are decided at the design stage after assessing the terrain, latitude and so on. Based on the design, the structures are fabricated with slots to move to the desired tilt angle according to the use in different seasons. Seasonal tilting activities are done manually.