Acciona Combines Wind And Solar Power

Wind power giant Acciona has installed flexible solar panels on the surface of a wind turbine tower at Breña Wind Farm in Spain.

120 of the 1mm thick Heliatek HelioSol solar panels occupy around 50 metres of the tower’s surface area and have a collective capacity of 9.36kW.

Unlike conventional solar cells that use silicon as the primary material, organic solar cells are made from carbon-based materials.

“The hybridization project in Breña means the optimization of the use of space for renewable energy production and it will enable us to test the efficiency of organic photovoltaics, a technology that we believe has one of the best improvement curves in terms of technological efficiency,” said Acciona Energy Innovation Director Belén Linares.

Cheap, Flexible Solar – But Lower Efficiency

Much research and development has occurred in the field of organic photovoltaics (OPV) over the last decade. While flexible, light, cheap to produce and able to printed on a roll-to-roll process, something holding back the technology back has been efficiency. Conventional silicon-based solar panels commonly used on rooftops have conversion efficiencies of around 16% – 19%, while the HelioSol product offers around 6-7%.

However, OPV efficiency has been steadily improving at a research level. In March this year, a team at  South China University of Technology demonstrated a conversion efficiency of over 16% for single-junction organic solar cells (OSCs). But it can be a long journey from the lab to the rooftop and silicon solar panels are likely to rule the roost for a while yet.

The use of OPV on the Acciona turbine isn’t primarily to export what would be the comparatively little amount of energy produced to the mains grid. It is being trialled to determine effectiveness in delivering energy for the operation of the internal systems of the wind turbine. These include auxiliary systems when the turbine is in operation and various functions when it is in shutdown mode in the event of lack of wind or maintenance; during which energy would usually be drawn from the grid.

Later on in the trial, battery storage may be introduced.

“The entire system is monitored with a view to evaluating it under real conditions, both from the point of view of energy production and degradation of the solar modules,” says Acciona.

Breña Wind Farm consists of two dozen 1.5MW Acciona AW-1500/77 wind turbines. Acciona currently has over 1,200 MW of renewable energy capacity either  in operation or under construction across the world. Its Australian projects include the Waubra, Gunning, Cathedral Rocks and Mt Gellibrand wind farms.