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Solar farm at sunset

Heriot-Watt University, in partnership with industry partners Wood, is building a model that aims to highlight the benefits of the country moving to double-sided solar panels (bifacial solar cells) rather than using the current single-sided panels (monofacial).

Bifacial cells can produce up to 25% more energy with the same projected area due to their ability to convert irradiation captured on both the front and rear sides. However, their current market share remains very low at around 5%.

Heriot-Watt University is recognised as the best in its field and we are thrilled to, once again, be working together to create a low-carbon future.

Alan Mortimer, director of innovation at industry partners, Wood

According to the Solar Trade Association (1), the installed capacity of Scottish solar panels will rise to 1.5GW by 2030. The 25% enhanced energy yield of bifacial versus monofacial panels with the same projected area, could mean generation would increase to almost 2GW.

This would equate to:

  • £400m of additional annual revenue to the Scottish economy
  • Over 2000 new jobs
  • £200m a year energy savings for Scottish industry and households
  • Over half a billion kgCO2/year emissions reduction

Dr Mehreen Gul, Assistant Professor from the School of Energy, Geoscience, Infrastructure and Society (EGIS) explains: “Although the development of bifacial solar cells dates back to the 1970s, due to the expensive cell structure, bifacial modules have remained a niche product in the market.

“In contrast to single sided cells, bifacial cells collect radiation on the front and rear side as they capture light reflected from the surface beneath the module and from the surroundings. On flat roofs, ground-mounted installations or locations that might not initially seem the best for a solar panel, bifaciality can improve energy generation by up to 25% more than standard panels.

“The advent of new and economically viable glass provides the ideal technology for generating higher energy yields. However, before this technology sees large-scale market distribution, several hurdles have to be overcome. Unlike single-sided panels, we need to examine the ‘albedo’ (light reflectivity) of the surface underneath the panel that can affect performance and then make accurate energy yield assessments by adapting and using state-of-the-art modelling tools. We will also perform a detailed investigation into high albedo surfaces in relation to radiation augmentation of bifacial modules, ageing, degradation, costs and environmental impact.”

Alan Mortimer, director of innovation at Wood, said: “Heriot-Watt University is recognised as the best in its field and we are thrilled to, once again, be working together to create a low-carbon future. Bifacial panels with their lower cost of energy will help accelerate the global energy transition by allowing many more companies and consumers to make the switch.

“Solar energy is one of the fastest-growing renewable technologies and through this partnership, we will not only drive continuous improvements for our customers but also boost the quality of research within the university by ensuring it has practical applications in industry.”

Scotland’s Energy Efficiency Programme (SEEP) aims to make Scotland’s buildings as close to zero carbon as possible by 2050. Combining storage with wind and solar assets such as bifacial solar cells with enhanced generation potential, presents a valuable solution for the energy system as a whole, offering opportunities for locally managed demand.

This kind of flexibility and control will be important with the uptake of heat-pump assisted electric heating and as electric vehicles become an integral part of the transport system.

The clean and increased on-site generation using bifacial panels, coupled with the development and use of innovative software, could also reduce the need for investment in more expensive and disruptive ‘hardware’ in the form of grid upgrades.

It is hoped the research will be used internationally to build a case for bifacial panels across the globe. An Energy Technology Partnership Award with contributions from Wood and Heriot-Watt University is funding the research. Input is also being provided by Edinburgh Napier University.