Most solar energy comes from single-sided panels laid flat or at an angle on a roof or in a field. However, vertical bifacial solar panels are starting to make their way onto farms and other places. These new panels use less space and can generate more energy, making them attractive.

A vertical bifacial solar panel is, simply, a panel with photovoltaic (PV) cells on both sides that is installed upright rather than horizontally to face east and west, so they generate electricity with sunlight that reaches one side in the morning and the other in the afternoon.

Research Shows Higher Output

Producing energy on both sides appears to lead to higher output. A 2018 study by LONGi, for instance, showed that vertical bifacial solar modules can increase energy yield by 5-30 percent, depending on factors such as the region, ground surface reflectivity, installation height, mounting, and inverter choices. Vertical bifacial solar panels have two energy peaks, one in the morning and one in the afternoon. Because they do not face south, bifacial PVs mounted vertically tend to stay cooler and that also adds to their productivity.

In addition, bifacial panels can benefit from the albedo effect when sunlight hitting the ground on a light surface is reflected back toward the panels, contributing to the energy generation, so they also perform best on ground surface with high reflectivity (high albedo), such as flat white roofs or sand.
Vertical panels also are less likely to be affected by snowstorms and hail.

They Optimize Space and Stay Cleaner

Space optimization is an important benefit of solar panels when space is limited. Because they are designed to be slim and vertical, the vertical installation also exhibited an exceptional ground coverage ratio, making it an attractive solution for space-constrained applications, according to an AL al-Bayt University study. In addition to being mounted on rooftops, they can act as fences or dividers on a property; they can be placed along highways or parks; they can be incorporated into the design of a parking lot without sacrificing any perking spots.

Photo Source: Greentech Renewables - Spring Hills Greens, Sandbox Solar, and Greentech Renewables Denver constructed a custom 26 kW DC bifacial solar fence to meet the farms' energy needs while optimizing their land use.

For example, according to PV Magazine, an innovative farming operation in Spring Hill Greens, Colorado installed vertical bifacial solar panels between two greenhouses. This not only minimized the land footprint, but also leveraged the albedo effect from the reflective greenhouse materials. The project’s peak generation periods are at 9 a.m. and 4 p.m.

In the same study, a vertical installation demonstrated inherent anti-soiling properties akin to self-cleaning.

A Solution for Agriculture

While traditional single-sided solar panels installed vertically are nothing new on farms and agricultural facilities, bifacial solar systems are different, and they are a relatively recent innovation.

One of the leaders in production is German startup Next2Sun, which has completed several projects in Germany and is working on a new installation in Vermont. Its agrivoltaic system uses land for both farming and solar power, IEEE noted, and has the advantage of minimizing the need for land. While the varieties of crops that can be planted under traditional solar panels are constrained, since plants need sun to grow, bifacial vertical solar modules allow more types of plants to grow more easily. Crops such as hay and potatoes are a great fit for this technology. Crops that grow higher, such as corn, could block the panels, however, so the installation need to be tall and can be more expensive. Research has also shown additional benefits, such as saving irrigation water.

Further development of the technology is ongoing. The German-designed Sunzaun's vertical solar system successfully passed UL testing, making it the first vertical solar system to achieve certification in the United States, according to PV magazine. Sunzaun vertical arrays were installed in 2022 within rows of grapevines at a winery in Somerset California, even before UL certification, demonstrating the dual-use ability of vertical PV technology. The solar array has 43 modules with 450 W each.

Lower Carbon Emissions

Researchers at Leipzig University noted that vertical PV systems can enable lower utilization of gas power plants or storage capacities because of the timing of the output. Traditional solar farms often produce an excess of electricity at midday but fall short during morning and afternoon hours. Vertical bifacial solar modules in an east-west facing direction can complement south-facing power plants and help stabilize the electricity grid due to electricity generation patterns for daytime use.

Wider usage of agrivoltaics using vertical bifacial solar panels that allow installation around more types of crops could have broader implications nationally as well. Co-developing land for both solar photovoltaic power and agriculture could provide 20 percent of total electricity generation in the United States, a paper by Oregon State University researchers found. Moreover, wide-scale installation of agrivoltaic systems could lead to an annual reduction of 330,000 tons of carbon dioxide emissions in the U.S and the creation of more than 100,000 jobs in rural communities, while minimally impacting crop yield. “Agrivoltaics provide true synergy,” said OSU associate professor Chad Higgins, by leading to more food, more energy, lower water demand, lower carbon emissions, and more prosperous rural communities. OSU primarily studied mono-facial panels, and vertical bifacial panels could lead to even more benefits.

In conclusion

Under favorable sunlight conditions, MarketWatch said, system owners can expect a 6 kW vertical bifacial solar system to generate around 9,000 kWh each year. At an average electricity price of 16 cents per kWh, 9,000-kWh of output is equivalent to $1,440 in annual savings. However, bifacial systems are about 10-20 cents per watt more expensive than mono-facial systems. EE Power found that the bifacial option could be minimally more expensive long-term due to energy yield increases.

Installation of vertical bifacial solar panels is still at an early stage and may not yet make sense for the average homeowner because of its higher cost and need for additional equipment. They show great potential for agriculture, commercial use and large-scale utility farms where they could provide significant advantages in a multitude of ways.