As mother nature continued to prove that weather is an unpredictable phenomenon this week, Sandia National Laboratories was developing a system that will help utility companies predict and prepare for weather variations that can affect power output. The new system monitors how cloud shape, size and movement affect large-scale solar PV power plants and, with the data the system collects, will help utility companies assess the situation to ramp rates and power output if necessary.
The research is being conducted at the 1.2MW La Ola Solar Farm on the Hawaiian island of Lana’i, which uses SunPower’s tracker technology. As it is the state’s largest solar power system and produces some of the highest rates in solar PV power penetration, researchers were looking to comprehend variability in a large plant to make certain that power output is dependable and that output ramp rates continue to be manageable.
“As solar power continues to develop and take up a larger percentage of grids nationwide, being able to forecast power production is going to become more and more critical,” said Chris Lovvorn, director of alternative energy of Castle & Cooke Resorts, which owns 98 percent of the island. “Sandia’s involvement and insight has been invaluable in our efforts to meet 100 percent of the island’s energy needs with renewable resources.”
Although extensive research has been done on the affects of cloud cover to small PV systems, there wasn’t enough documented analysis of what happens to a large-scale system when only a part of the large system is covered by a moving cloud. Sandia researchers could not get in the way of the operations plant, but were able to conduct their study by connecting 24 small, nonintrusive sensors into the plant’s PV panels. Using a radio frequency network to send the data, the sensors recorded data at one-second intervals allowing the researchers to understand more about cloud direction and coverage activity on the large-scale system.
“Our goal is to get to the point where we can predict what’s going to happen at larger scale plants as they go toward hundreds of megawatts. To do that, you need the data, and the opportunity was available at La Ola,” said Sandia researcher Scott Kuszmaul.