IEEE Power Electronics Magazine - June 2022 - 42

Sustainable Sources of Green
Electric Power Generation
and Storage
Based on abundance, free fuel, minimum
amount of GHG emissions, minimum
use of water in power generation,
highest safety, access to all, and ultralow
cost, solar and wind energy are the
only two energy sources for generating
green sustainable electric power [13]-
[15]. Due to advancements in technology
and ultra-large-scale manufacturing,
lithium-ion batteries (LIBs) are
emerging as a cost-effective solution
of electric power storage due to its
constantly reducing cost as seen in Figure 3 [16]-[17]. In
addition to consumer products and electric vehicles, LIBs
are also emerging as a low-cost practical solution at utility
scale to address the intermittency of solar and wind
energy [14]-[15]. Free fuel-based solar and wind electric
power generation combined with batteries for storing electric
power has the potential to electrify almost everything.
Free fuel-based solar
and wind electric
power generation
combined with
batteries for storing
electric power has the
potential to electrify
almost everything.
converted back to dc power internally
in all dc loads. More than 30% power
and capital is wasted in this process
[18]. Extremely fast charging of electric
vehicles (EVs) requires dc power.
As shown in Figure 4 [19], the ac
power supplied by the grid is first converted
to dc power inside the charger.
The components shown in blue color
in Figure 4 will not be required if the
power source is dc. Another aspect of
ac power is that a fortune is invested
to regulate the frequency of the ac
grid. Thus, from the point of view of
capital cost and overall cost of generMyths
and Facts about DC vs AC Power
Except for few inductive loads, virtually all our loads (electronics,
solid-state lighting, efficient motors etc.) need dc
power as the input power. However, based on the outcome
of the " war of currents " in the beginning of the last century,
the entire world is using ac power-based electricity infrastructure.
Power industry has realized the importance of
semiconductor-based electronics but has used it only to
facilitate the control, conversion, and distribution of ac
power. Solar energy-based photovoltaics generates dc
power. Batteries and fuel-cells store dc power. Erratic wind
power is first converted to dc power before converting to ac
power for transmission and distribution. Thus, dc power
generated today by free fuel sources is first converted to ac
power. After transmission and distribution, the ac power is
1,000
2,000
3,000
4,000
5,000
6,000
7,000
8,000
1990
1995 2000 2005
Date
Ziegler Ms, Trancik JE. Energy and Env. Science. 2021.
2010 2015 2020
FIG 3 Lithium-ion battery cost reduction [16]-[17].
42 IEEE POWER ELECTRONICS MAGAZINE z June 2022
ated electric power, we need to devise a plan that can be
implemented for dc-based electricity infrastructure. However,
an immense amount of capital, research, and time has
been invested in the current ac-based infrastructure. Thus,
we are not proposing to dismantle the existing ac power
infrastructure. Other than the existing loads, new loads
(e.g., charging of electric vehicles, desalination plants, etc.)
are emerging that can be served at a lower cost with a dc
power network as compared to the existing ac grid. After
retirement of the existing ac infrastructure, new infrastructure
can be based on dc power. The power networks architecture
proposed in the next section has the potential to
transform the global electricity infrastructure and provide a
solution to climate emergency by providing efficient dc-dc
conversion to achieve an edge over the ac power-based grid.
All Types of Cells
Power Electronics as an Enabler
The growth of semiconductor-based switching transistors in
the integrated circuits (IC) industry has become a boon to
the power electronics industry. The availability of high frequency
switching transistors has enabled higher efficiency
converters to convert dc power to ac power in inverters and
transformers. Silicon (Si) based insulated-gate bipolar transistor
(IGBT) has been the workhorse of the power electronics
industry. The fundamental limits of silicon power
electronics can be overcome by the utilization of silicon carbide
(SiC) transistors in place of silicon transistors. SiC
modules are providing higher power density of motor drive
of electric vehicles [20]. The ac power network has sustained
so far due to the ability of effective voltage conversion
by transformers enabling long distance transmission of
ac power with minimal losses. However, due to the advent
of SiC power electronics, dc-dc voltage conversion can
also be efficiently implemented. The following sub-sections
explain our proposed dc power-based network for
the most efficient utilization of green sustainable electric
power through solar, wind, and batteries. Sub-section A
illustrates a local dc power network, and sub-section B
includes transmission for a DC network at a larger scale.
Key aspects of SiC-based power electronics for high voltage
dc-dc conversion are described in sub-section C.
Price (2018USD Per kWh)
IEEE Power Electronics Magazine - June 2022

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