Bifacial Solar Panels That Follow The Sun Now Most Cost Effective

A bifacial solar panel is a solar panel that can collect energy from the front side and the rear side (a normal monofacial panel only collects energy from one side). Bifacial solar technology was created in the latter 1960s. It was dormant while the broader PV market exploded. It was too costly for the incremental energy production improvements.

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Bifacial solar panels on trackers. Credit: NPC

A bifacial solar panel is a solar panel that can collect energy from the front side and the rear side (a normal monofacial panel only collects energy from one side). Bifacial solar technology was created in the latter 1960s. It was dormant while the broader PV market exploded. It was too costly for the incremental energy production improvements.

A CleanTechnica field trip and series of articles a couple of years ago mentioned, though, that bifacial solar cells and panels are moving more seriously into play thanks to cost drops and efficiency improvements. A recent scientific article published in the journal Joule confirms our earlier belief, based on time with Array Technologies engineers and founder Ron Corio at their factories and offices, that this technology has promise.

Technology that tilts panels so that they can follow the sun boosts the electricity production of normal solar panels. This solar tracking is used in some solar projects, especially large ones in certain regions, but hasn't been used in most. Bifacial solar PV technology, however, can get an especially useful boost from solar tracking technology, capturing much more sunlight than a normal solar array ever could.

The new report, "Global Techno-Economic Performance of Bifacial and Tracking Photovoltaic Systems," confirms that tilting toward the light, for optimal sunlight collection from both sides, can be the most cost-effective solar option to date. The report determined that this combination of technologies produces almost 35% more energy, on average, than immobile single-panel photovoltaic systems. This reduces the cost of electricity by an average of 16%.

Image courtesy Joule [PDF].

"The results are stable, even when accounting for changes in the weather conditions and in the costs from the solar panels and the other components of the photovoltaic system, over a fairly wide range," says first author Carlos Rodríguez-Gallegos, a research fellow at the Solar Energy Research Institute of Singapore, sponsored by the National University of Singapore. "This means that investing in bifacial and tracking systems should be a safe bet for the foreseeable future."

The research article notes that most of the current PV installations use monofacial crystalline silicon PV modules with a fixed-tilt system setup. Things are going to change, though, as the more cost-competitive technology is apt to disrupt this dominance.

"The results reveal that bifacial-1T installations increase energy yield by 35% and reach the lowest LCOE for the majority of the world (93.1% of the land area). Although dual-axis trackers achieve the highest energy generation, their costs are still too high and are therefore not as cost effective. Sensitivity analyses are also provided to show the general robustness of our findings."

Dual-axis trackers become more competitive as you get closer to the poles.

Also, despite evidence that bifacial solar panels with single-axis tracking is more cost efficient, Rodríguez-Gallegos doesn't expect a rapid switch to this tech.

"The photovoltaics market is traditionally conservative," he says. "More and more evidence points toward bifacial and tracking technology to be reliable, and we see more and more of it adopted in the field. Still, transitions take time, and time will have to show whether the advantages we see are attractive enough for installers to make the switch.

"As long as research continues to take place, the manufacturing costs of these materials are expected to keep on decreasing, and a point in time might be reached when they become economically competitive and you might see them on your roof," says Rodríguez-Gallegos. "We then aim to be a step ahead of this potential future so that our research can be used as a guide for scientists, manufacturers, installers, and investors."

"(A) Estimated LCOE worldwide for monofacial fixed-tilt (m-fixed) installations. (B–F) The following plots present the percentage difference between the LCOE (with respect to monofacial fixed-tilt) for (B) bifacial-fixed, (C) monofacial-1T, (D) bifacial-1T, (E) monofacial-2T, and (F) bifacial-2T." Image and caption courtesy Joule [PDF].

The full report is here.

A judge blocked Trump's attempts to undo a bifacial solar module duty exemption. The judge's decision to block those duties on bifacial solar modules is expected to preserve jobs in the US. Of additional help in the short term:

"The US government made good on its promise earlier this month of a reprieve around tax credits for solar (ITC) and wind (PTC), announcing this week renewable developers will have an extra year to qualify for the government incentive.

"The extension of the safe harbor provisions – which firms use to put down the initial 5% of project costs to fully reap the ITC and PTC credits – is meant to help operators facing COVID-19 delays, the US Treasury and the Internal Revenue Service (IRS) said as they outlined the changes this week."

"Today's action shows that solar energy is an economic driver with bipartisan appeal," the Solar Energy Industries Alliance (SEIA) wrote in response.

Solar trackers under solar modules. Image used with permission of Array Technologies.

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Cynthia Shahan started writing after previously doing research and publishing work on natural birth practices. (Several unrelated publications) She is a licensed health care provider. She studied and practiced both Waldorf education, and Montessori education, mother of four unconditionally loving spirits.

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