Performance of Agrivoltaic Systems for Shade-Intolerant Crops: Land for Both Food and Clean Energy Production
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CitationSekiyama, Takashi. 2019. Performance of Agrivoltaic Systems for Shade-Intolerant Crops: Land for Both Food and Clean Energy Production. Master's thesis, Harvard Extension School.
AbstractThe purpose of this research is to examine the performance of agrivoltaic systems, which produce crops and electricity simultaneously, by installing stilt-mounted photovoltaic (PV) panels on farmland. As PV power stations continue to enjoy remarkable growth, land occupation with the purpose of establishing solar farms will intensify the competition for land resources between food and clean energy production. In a bid to reduce this competition, previous studies have suggested the use of agrivoltaic systems, which produce shade-tolerant crops such as lettuce under PV modules. However, if agrivoltaics work well only for some shade-tolerant crops, as existing studies seem to infer, their practical applicability would be very limited. Thus, this research explores the performance of an agrivoltaic farm producing corn, a typical shade-intolerant crop. The research was conducted at a 100-m2 experimental farm with three sub-conﬁgurations: no modules (control), low-module density, and high-module density. Eight 0.76-m-wide PV module arrays, spaced at 0.71 m intervals comprise the high-density conﬁguration, while four PV module arrays spaced at 1.67 m intervals comprise the low-density conﬁguration. In each conﬁguration, 25 corn stalks were planted 0.5 m apart (9 stalks/m2).
The results showed that the stilt-mounted agrivoltaic system can mitigate the trade-off between crop production and clean energy generation even when applied to shade-intolerant crops. First, the biomass of corn stover grown in the low-density PV module configuration was larger than that of the no-module control configuration by 4.9%. Second, the corn yield per square meter of the low-density configuration was larger than that of the control by 5.6%. Third, the total annual revenue of the high-density configuration was 8.3 times larger than that of the control, while that of the low-density configuration was 4.7 times larger. Furthermore, according to the cost-benefit analysis for this case study, a good return on the investment is likely for such agrivoltaic systems. The cost-benefit ratios of high-density and low-density configurations over a 20-year period were 1.898 and 1.779, respectively, indicating that both systems would be financially feasible.
The results of this research should encourage more conventional farmers, clean energy producers, and policy makers to consider adopting stilt-mounted PV systems. Beyond its applications in agriculture, this system has the potential to generate electricity on pasture land, water surfaces, roads, and many other places without devastating the natural environment. Particularly in densely populated regions, mountainous areas, small inhabited islands, and barren desert areas, where land resources are relatively scarce, this system could exploit limited land resources for simultaneous food and clean energy production.
Citable link to this pagehttp://nrs.harvard.edu/urn-3:HUL.InstRepos:42004145