Greenhouses with transparent solar panels provide themselves with electricity

Greenhouses equipped with transparent solar panels collect energy by absorbing only those waves of light

the length of which is not needed by plants for the process of photosynthesis.

“Plants use only a few wavelengthslight for photosynthesis, and the idea is to create greenhouses that produce energy from this unused light, while at the same time allowing most of the photosynthetic light to pass through,” says Brendan O'Connor, study author and assistant professor of mechanical engineering and in Aerospace Engineering at North Carolina State. “We can do this using organic solar cells because they allow us to tune the spectrum of light that the solar cell absorbs – so we can focus on using wavelengths of light that are not used by plants. However, until now it was not clear how much energy a greenhouse could harvest if it used these translucent, wavelength-selective, organic solar cells.”

The researchers used a computational modelto estimate how much energy a greenhouse can produce if it has translucent organic solar cells installed on its roof, and whether that energy will be enough to offset the amount of energy the greenhouse needs to operate efficiently. The model was developed to estimate the energy consumption of tomato greenhouses in locations in Arizona, North Carolina, and Wisconsin.

“Most of the energy consumption in greenhousescomes from heating and cooling, so our model focused on calculating the energy load required to maintain the optimal temperature range for tomato growth,” says O'Connor.

In Arizona, greenhouses can become energeticallyneutral, without requiring an external energy source and at the same time blocking only 10% of the photosynthetic strip of light. However, if manufacturers want to block more photosynthetic light, they can generate twice as much energy as the greenhouse needs. In North Carolina, a greenhouse can become energetically neutral, blocking 20% ​​of photosynthetic light. In Wisconsin, greenhouses could not become energetically neutral using translucent solar cells — too much energy is required to keep the greenhouse warm in winter. However, solar cells can satisfy up to 46% of the greenhouse requirement.