Agrivoltaics, which combines solar power and food growing, has ballooned to more than a $14B industry already and is expected to grow to $49B in the next five years . It turns out that in many cases partially shading crops with solar panels generally makes more food than full sun . This non-intuitive result has farmers clamoring to make more money on their land as they get revenue both from food like normal but also the value of the solar electricity, which tends to be much larger. Both color and transparency of partially transparent solar panels not only impact how much electricity you get, but also crop yield in agrivoltaic systems. Most of the time it is good – for example tomato and turnip yields were way up, but sometimes there is a slight loss of crop mass like beans , but it is more than made up for my increased revenue from the sale of solar energy. How is a farmer supposed to know ahead of time if shading crops with solar panels makes economic sense? How do they know which solar panel to use as they now come in a dizzying array of colors and transparencies? A new study proposed a way to determine design parameters for controlled environment agrivoltaics using a backyard hack. The hack was used to increase the growing season in northern environments.

What To Do With Old Crates? Turn Them Into Solar Power Cold Frames

It is a screening study growing lettuce in cold frames under the shade of 55% semi-transparent neutral, red, blue, and green thin film solar panels in controlled cold-frame environments. Previous work has shown that one of the ways we can get energy for our EVs is to use agrivoltaics, so it is only fitting to use the waste from the EV industry as sources of building materials. Visible light spectra were taken inside the cold frames upcycled from EV-charging station crates for each type of solar module to quantify the spectral energy reaching the lettuce plants. The solar cold frames were modeled for electrical performance and the agrivoltaic impact on lettuce crops were monitored for air temperature and soil temperature (hourly) and height and leaf count weekly. Finally, the overall yield in each agrivoltaic setup and control was measured by mass of lettuce and compared to a control given identical nutrition and water.

Solar Cold Frames to Grow Food and Power

Although the impact of agrivoltaic treatment was mixed in terms of number of leaves, all agrivoltaic treatments had greater height than the control. Overall, agrivoltaic systems created microclimates in the cold frames that enhanced lettuce productivity: neutral semi-transparent modules produced 300% more, green 210% more, red 161% more and blue 120% more yield than the lettuce grown in open air environments . This and a few of these solar cold frames in the backyard could power a small house.

Based on the results, the balanced light spectra through neutral semi-transparent solar panels supports both plant growth and solar power generation and was found to be the preferred agrivoltaic design of lettuce under 55% transparent conditions. The designs for solar cold frames are freely available so anyone can do these screening experiments quickly where they live. The potential of agrivoltaic systems to enhance land-use efficiency is pretty clear – you get lots of renewable energy and improve rural economic resilience by providing a secondary revenue stream.