Page 119 - CW E-Magazine (6-2-2024)

Point of View

Energy transition will accelerate demand for

speciality chemicals & materials

The chemical industry is seen as an enabler of manufacturing and modern living, and is not an optional industry that a large economy
like India can do without developing substantially. This aspect is widely recognised in the industry, but less so by the public, and somewhere
in-between by governments. This state-of-affairs is partly due to the inability of the industry to convincingly put across its utility, letting
policymaking be misdirected in instances.

Demand for speciality chemicals, which are differentiated and/or high value offerings sold on the basis of performance as much as chemical
identity, is driven largely by GDP growth and per capita income. As both rise, and especially if there is an emphasis on manufacturing (as
is the case in India), demand for speciality chemicals will get a leg-up. Prosperity brings sophistication in consumption, and this will drive
demand for higher performance products, which (hopefully) have better margins and profitability for their suppliers.
The energy transition, well and truly upon us, aims for fossil-free energy supply with increasing use of renewable energy sources such as
wind, solar, biofuels, and hydrogen, amongst others. All need myriad inputs from the chemical industry and offer new market opportunities
for incumbents and new entrants alike. In many aspects, the energy transition can be described as a materials transition as well.

As solar and wind power are the two principal renewable energy platforms the world is expected to rely on, it is relevant to look at the
role of chemicals and materials in them.

Solar power
Installed capacity for solar power has expanded rapidly in recent years (globally and in India), and the trend is expected to be maintained.
The expansions have been driven by the falling costs of solar photovoltaic (PV) cells and panels stemming in large measure from economies
of scale as new manufacturing capacity is added (mainly in China), as well as government support and incentives, such as those offered
to investors in India.

The most widely adopted PV cells are based on crystalline silicon, but this technology has evolved. Single silicon passivation emitter
rear contact (PERC) cells now command a market share of 84% (in 2021), from 6% in 2016, effectively replacing polysilicon back surface
field (BSF) cells.
Monocrystalline PERC cells are cut from a single piece of silicon, unlike polycrystalline panels, which are made using a blend of silicon
shards. Though the former are more expensive than the latter, their higher efficiency more than makes up, making them today’s preferred
choice even on overall cost considerations. In addition, because they make better use of space, fewer modules are required to produce the
same solar output compared to a standard silicon panel.
The silicon wafer fabrication process involves several chemicals, including high purity versions of some commodities, which sell at prices
orders of magnitude higher in some instances. These include hydrochloric acid, sulphuric acid, hydrogen peroxide, ammonium hydroxide,
and various photoresist materials. They are used for cleaning, etching, and deposition processes during the fabrication of silicon wafers.

The importance of polymeric materials is exemplified by the back-sheet in a solar panel that protects and supports the PV cells. It needs
to have excellent resistance to high temperature, UV radiation, and environment-related ageing, to ensure a long life of the assembly. The
back sheet is usually a composite – with a polyethylene terephthalate (PET) polyester film as a core layer, and outer layers dominated by
fluoropolymers such as polyvinylidene fluoride (PVDF) or polyvinyl fluoride (PVF). The primary function of the inner or cell side layer of the
back-sheet is adhesion with the encapsulant and blocking the UV rays coming from the front/cell side; while the outermost layer protects the
PV cells from environmental stresses like dust, moisture, etc. Though glass is also used as a back-sheet, polymeric materials find favour due
to their better safety, light-weight and lower costs. One way of reducing the cost of the back-sheet even further, while maintaining satisfactory
behaviour and durability, is to reduce the number of fluoropolymer layers from two to one. In this case, the layered structure is formed mainly
with PVF or PVDF on the airside and with PET or ethylene vinyl acetate (EVA) layers on the inner side. A more recent development in the
back-sheet does away with fluoropolymers in toto, substituting it with hydrolysed PET (H-PET) on the air side.

PV cells as mounted in modules are encapsulated with a polymeric material to protect against weather, corrosive environment, UV
radiation, low mechanical stress, and low energy impacts. The most preferred encapsulate is ethylene vinyl acetate (EVA) film, with 76%

Chemical Weekly February 6, 2024 119

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