Solar Panels in Orchards – research from the Tatura SmartFarm

Video Transcript

Hi, my name's Ian Goodwin. I'm with Alessio Scalisi. We both work for Agriculture Victoria at the Tatura SmartFarm.

Today we're standing in front of our agrivoltaics experiment which we call Panels Over Pears. We are looking at the effect of solar panels on fruit yield and fruit quality, and this has been going on for about four years now. We installed them over four years ago, so we've got quite a lot of data to represent what effect panels might be having over pear crops.

So, Alessio, first of all, based on how we've set this up, approximately how much radiation do these solar panels intercept?

Yeah, so we've got two different treatments. The treatment with panels oriented to the west at 45 degrees intercepts around 40% of the incoming radiation. While the treatment with panels at five degrees to the west, intercepts about 47%, which is substantial in both cases. Yeah. So, in other words, that creates quite a bit of shade on the trees during the daytime. Yeah. And potentially that could impact on the yield and fruit quality. Yep.

So, first of all, during the years we've been doing this, we've had quite a lot of different climatic events happening, including hail, significant hailstorm as well as of course, you know, we've had exceptionally, in particular this year, an exceptionally hot summer. So, first of all, what did the panels do with respect to protecting the fruit from hail and from radiation? Yeah. So, two years in a row we had these pretty severe hailstorms, and they damaged about 30%, 35% of our crop in control conditions. With the panels on top, we were able to substantially decrease the damage on fruit, and it went down to about 13% in the case of panels at five degrees to the West. So, we were pretty impressed with those results and as expected, you know, having something on top of the canopies will protect you from hail. Of course, it depends on the direction of the hailstorm. In that case it was a predominantly a South-westerly storm, and that's the kind of number we got.

In terms of sunburn in the two seasons with high radiation and high temperatures, so the first year and this very last year, we saw that on average the sunburn damage in control condition was between 5 and 7%. In the case of the solar panels, we were able to reduce the damage to less than 1%, so it became insignificant.

Yeah. Thanks. That's great. So yeah, so that's one thing, protecting the crop from hail and sunburn damage, but what do we find with respect to yield and fruit quality? So, they're obviously pretty important.

Yeah. So, the effect on yield is pretty severe, so over four years we can say that there was a reduction of about 35% in the 45-degree West treatment, while there was a reduction of even more, up to 45% in the case of panels oriented to the West of five degrees. So, the yield reduction over four years was significant. This is due to, particularly to a reduction in crop load, but also to a reduction in fruit size. Although the last year, we didn't see this effect because the crop load in the control trees was more than doubled than other treatments. Then in terms of fruit quality, of course, this is, what we're growing here is a blush pear that needs that red coverage on one of the cheeks of the fruit, and what we have seen is that, of course, removing that level of light, so again, 40% in the case of 45 degrees West, and 47% in the case of five degrees West, basically reduces the blush coverage to values that wouldn't make it marketable as a blush pear. So, it becomes a significant negative effect on this particular cultivar. That said, so we think on other pair varieties like Packham or, green pears, the effect on quality wouldn't be that severe.

So, so these are rigid panels, fixed, in other words, in place. We can't, you know, manoeuvre them or anything like that. Classical type, solar panels. But what do you think in respect to, obviously, we are intercepting a lot of radiation, causing a lot of shading within the trees. So, is it about trying to just put smaller panels or are there other new technologies that have come along since we established the experiment here? Yeah. So smaller panels, of course, would help with colour development and maybe yield reduction. But at the same time, they wouldn't generate the same level of protection against hail and sunburn. So, we think actually the best strategies are towards being able to move these panels at different times of the day, different times of the season, so that the light interception is higher when we need higher light interception, or in other cases we need to embed these micro cells or mini cells, photovoltaic cells with checkerboard kind of style designs.

Ultimately, there is technology that's come along in leaps and bounds, and so we still think there's opportunities to use, integrate solar into protecting crops in this particular case, you know, in pears, but of course other crops as well. Yeah. Okay, thanks Alessio.