Page 87 - A Comprehensive Guide to Solar Energy Systems

82 A COMPrEHENSIVE GUIdE TO SOlAr ENErGy SySTEMS

In countries with a widespread electricity grid, such as the United Kingdom, PV is
used primarily for in-grid, domestic, and small unit generation. Because in-grid systems
do not require localized energy storage, in-grid PV can be considered separately from
energy storage. However, one of the great advantages of PV solar energy generation for
those regions of the world without a good electricity grid is the possibility for small-
scale localized off-grid generation. For off-grid PV, solar energy generation and storage
technologies are required, and sustainable energy storage becomes atleast as important
as sustainable energy generation. It is with this combined problem, sustainable energy
and storage that this chapter is concerned.

To explore off-grid solar in the United Kingdom, d.A. Worsley’s team has constructed
a building monitored to test and validate localized, off-grid, solar energy collection and
storage at the SPECIFIC Innovation and Knowledge Centre in Swansea University [6].
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This ∼200 m building demonstrates the ‘buildings as power stations’ principle be-
ing developed at SPECIFIC using technologies embedded into the building envelope
to generate, store, and release energy (Fig. 5.1) [7]. The building has a 17 kWp building
integrated photovoltaic roof installation, transpired solar air collectors integrated into the
south elevation for heating, and 60 kW h capacity of aqueous hybrid ion batteries (C2C
certified) for clean and safe energy storage [8].
In Africa, PV offers the possibility of localized electricity generation for the millions
of African homes, schools, and clinics, without grid connection, and one of the authors
(Mld) worked with a team from Swansea University on a project to install a small-scale
off-grid solar energy structure with integrated photovoltaics for an orphanage in Mutende,
lulamba, Zambia [9]. The total installed capacity of the solar cells was 1.6 kWp. Two 12 V,
102 A h lead-acid batteries were used for electricity storage (Fig. 5.2).
In this chapter, we discuss the problem of sustainable solar energy generation and
storage for rural SSA, and how generation and storage technologies can be integrated into
a circular economy to improve sustainability. We begin with the climate and geography,
both physical and human, of the region; then introduce the ideas of the circular economy,
discuss silicon PV in light of these ideas, identify a basic energy requirement for rural
households using South Africa as an example, consider the sustainability issues over the
lifecycle of a low cost PV and energy storage system capable of meeting this requirement,
and finally, discuss briefly current developments in PV technology, and how these might
be used in this application.

5.2 Geography

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SSA comprises 49 countries, covers an area of 24.3 million km (Fig. 5.3), and spans four
time zones [10]. This vast region accounts for more than 15% of the Earth’s land surface
and has landmass in all four hemispheres. More than half of SSA lies between the Tropics
of Cancer and Capricorn, and as such the area is mainly influenced by a tropical climate,
although there is high variability across the region [11].