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296 CHAPTER 9 Design Principles of Photovoltaic Irrigation Systems

1. INTRODUCTION
Today, in the 21st century, humanity faces multiple, closely interrelated global chal-
lenges, such as the increasing world population. In 2017, world population surpassed
7.4 billion inhabitants (https://www.populationmatters.org/). This growing popula-
tion requires food and energy, and, as a result, food security has become a global
concern. Malnutrition affects many countries on the planet and constitutes a major
obstacle to both global food security and sustainable development worldwide. One
out of three people in the world is undernourished, and it is expected that this figure
will reach one out of two in 2030 [1,2]. In addition to the need for food, energy needs
have seen a 3% annual growth rate over the last 15 years [3]. The gradual depletion
of fossil fuel resources [4] and its associated effects have encouraged the use of new,
clean, and renewable energy sources [5e7], such as solar energy.
Other major concerns for humankind are climate change and global warming.
They threaten with undesirable consequences such as biodiversity loss, desertifica-
tion, lack of freshwater and migratory flows, and abandonment of many regions in
the world affected by the said problems.
Agriculture, as a fundamental primary activity for the planet, should contribute
to the mitigation of the consequences of the abovementioned problems. A paradigm
shift would then be required regarding agricultural activity in general; it must
become not only a fully sustainable and more energy-efficient activity but also a
source of energy rather than a sink. This change of paradigm must be supported
by scientific and technical developments. Recent approaches such as Precision Agri-
culture, Agriculture 4.0, and Agrivoltaic Production are currently laying the founda-
tion of a new agricultural model. Agrivoltaic production approach has been defined
and studied by many authors [8e13], and it entails an alliance of both agricultural
and renewable energy production, namely photovoltaic (PV). The intrinsic effi-
ciency of the photosynthetic process is currently quite low (about 3%), while the
commercially available monocrystalline PV solar panels have an average efficiency
of 16%. Agrivoltaic production entails combining solar panels and food crops on
farms in such a way that the economic return is optimized. The results of the prelim-
inary studies indicate that the agrivoltaic systems can significantly increase the pro-
ductivity of farms. Dupraz et al. [13] report that this increase may reach a value
between 35% and 73% of the land productivity. Thus, new agriculture should not
only be self-sufficient energetically but it should also generate an energy surplus.
At the same time, agrivoltaic production must take into account environmental is-
sues, such as water and carbon footprints, as well as social and economic
considerations.
PV irrigation is one of the most promising alternatives for rural electrification.
The idea of using solar energy to meet the water needs of crops began in the
1970s. The first PV irrigation installations carried out at that time used pumps
coupled to direct current (DC) motors, connected directly to the PV array. In