A big part of the solar success story is the growing use of tracking systems. Tracking systems, which move solar panels to follow the sun across the sky, have long been available, but recent breakthroughs have brought down costs, making them more financially attractive. According to Berkeley Lab, solar trackers accounted for 80% of installations in 2017, among projects larger than five megawatts.
Nextracker is involved in more than 750 MW of commercial bifacial projects in U.S., he said. Invenergy completed financing in December for the 160-MWac Southern Oak Solar project in Georgia, with power being sold to Georgia Power under a 30-year contract. The project is under construction now, using Nextracker’s single-axis trackers.
Companies are also looking at digital controls to improve performance. Conventional trackers, going back to the 1980s, are basically timers, set to move the panels in time with the movement of the sun across the sky. While the sun is indeed predictable, clouds are not, and panels can shade each other if they are not on perfectly flat terrain.
Tracker companies are now using sensors and controls that monitor actual sunlight and move each row of panels individually to maximize output. As clouds change direct sunlight into diffuse light, for example, panels are better off pointing straight up to capture a maximum amount of diffuse light, rather than pointing at the blocked sun. And when the sun is low in the sky, the angle of each row of panels can be adjusted to minimize shading on the row behind it, called “backtracking.”
Once a project has committed to tracking hardware, the marginal cost of software monitoring and controls is minimal. Tracker companies are taking advantage of the revolution in microchips and wireless communications, giving each row of panels the intelligence to optimize production.
Speaking at a Bloomberg New Energy Finance event last March, Bryan Martin of DE Shaw Renewable Investments, which owns 2,000 MW of renewables in the U.S., described how Nextracker’s TruCapture Smart Control System boosted output at the company’s 74-MW solar project in Mississippi. “We’ve been running it for eight months and are getting materially more production, about 3.5%,” he said. “So, we are applying it to a lot of our different sites.”
Read the article in Power Magazine here.