Wind-solar hybrid plants up to twice as efficient

22 April 2013

Solar and wind power generation complement each other better than previously thought, according to a study released by the Reiner Lemoine Institut and Solarpraxis AG.

Combining wind turbines and photovoltaic systems results in up to twice the amount of electricity being generated across the same surface area, while shading losses caused by wind turbines amount to a mere 1 to 2% – much less than previously thought.

As an additional benefit, the construction of hybrid power plants does not require grid expansion because the plants generate wind and solar power at different times of day and during complementary seasons, ensuring the level of energy fed into the grid is more steady than that of wind or photovoltaic power plants alone.

"Until now, it was thought that the shadows cast on solar plants by wind turbines led to high yield losses. The study shows, however, that these shading losses are much lower than expected, provided the hybrid power plant is well designed," said Alexander Woitas, head of the engineering department at Solarpraxis AG, parent company of pv-magazine.com.

Various scenarios were simulated for the study and detailed shading analyses were carried out.

"Initial requests to create yield reports as well as technical and economic system planning have given us cause to hope that the more efficient utilization of space and infrastructure created by hybrid power plants has excellent prospects for the future," said Dr. Christian Breyer, managing director of the Reiner Lemoine Institut. "We also calculated what effects combining photovoltaic and wind power plants will have on power grids on both a global and regional level. The fact that wind and photovoltaic power supply the grid with much more stable levels of energy when working together has a positive effect on grid stability," he added.

While wind turbines produce a lot more electricity during the colder parts of the year, due to greater levels of wind over the winter months, solar power plants generate more solar power in the summer, compensating for the lower wind power production at this time of the year.

Next year, a photovoltaic system at Templin, near Berlin, is set to be retrofitted with wind turbines as part of the German government's Zwanzig20 research initiative.

Data from the pilot plant will be analyzed by Solarpraxis, the Reiner Lemoine Institut and project partners.