Designing Vitivoltaic systems for hot, dry vineyards: biophysical responses, wine quality and stakeholder perspectives

Abstract

This study examines vitivoltaics, where photovoltaic panels are installed in vineyards to generate renewable energy while also providing partial shade to the vines. With climate change bringing more heat and more frequent heatwaves, plus greater pressure on limited water resources, vineyards in hot, dry regions such as South Australia need ways to protect grape production and wine style while reducing their carbon footprint (Jones et al., 2005; van Leeuwen & Darriet, 2016). Vitivoltaic systems may help by moderating the vineyard microclimate while supplying on site clean energy (Marrou et al., 2013; Barron-Gafford et al., 2019).

At Adelaide University’s Waite Campus, experimental trials were conducted over three growing seasons using mock photovoltaic panels to create controlled shading treatments, building on previous work on shade and canopy microclimate effects on grapevine performance and wine composition in warm regions (Caravia et al., 2016). These experiments examined how shading affects vine growth, canopy structure, photosynthesis and berry composition in a warm, low rainfall environment. Across seasons, the vines adjusted to partial shading by increasing leaf area and internode length. There were small reductions in carbon dioxide assimilation, but yields were maintained. Grapes grown under the panels ripened more slowly but still reached full maturity. They tended to have higher acidity and nitrogen, which are useful traits for winemaking, while sugar and flavonoid levels were similar to fruit from unshaded vines. Sensory analysis showed that wines made from shaded grapes were of comparable quality to those from control vines when harvested at the same target ripeness, suggesting that partial shading can alter the ripening pattern without necessarily changing wine quality.

To see how vitivoltaics might work in a real terroir context, we also draw on observations from a commercial vitivoltaic set up next to a winery cellar door in a hot, dry South Australian region. This site allows us to explore how photovoltaic structures interact with local soils, topography, mesoclimate and management to influence vine performance, wine quality and visitor experience, in line with contemporary views of terroir as an interaction between natural and human factors (van Leeuwen et al., 2004). Feedback from stakeholders and consumers on vitivoltaics indicates broad acceptance and a sense that renewable energy infrastructure can be part of a modern expression of terroir under climate change. Overall, the results suggest that vitivoltaics can act as a climate adaptive and terroir sensitive approach that supports reliable grape yields and wine quality while improving the environmental sustainability of vineyards in hot and dry regions.

References

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