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U S T . H K
Pollutant emissions are largely a byprod-
uct of our need for energy generation and
transportation, which today are usually
powered by fossil fuels, namely oil, coal
and gas. One major emission is carbon
dioxide, a greenhouse gas that contrib-
utes directly to global warming when
generated in quantities that outstrip
nature’s assimilative capacity. Others,
such as particulate matter, are toxic to
human health. Yet currently, only 2%
of energy is derived from “clean air”
renewables, such as wind and solar.
The key challenges for renewables
include stability in generation, on-tap
availability, cost-efficiency, and high
performance. Wind farms require large
areas of land and highly efficient solar
panels are often expensive to produce.
Both face an “intermittent generation”
problem and energy storage to cover such
gaps remains a huge challenge.
HKUST researchers have set out
to address these complex issues that
often cut across conventional academic
disciplines and boundaries.
Fuel Cells
Prof Tianshou Zhao has been advancing
the potential for wider use of clean energy
for the past 15 years through his ground-
breaking work on direct alcohol fuel cells
and advanced battery technologies.
Prof Zhao sees immense potential in
fuel cells as an alternative source of ener-
gy. Fuel cells generate electricity through
converting the chemical energy
of a fuel such as hydrogen, eth-
anol and methanol, all of which
can be directly produced from re-
newable sources. Fuel cells have
high efficiency of around 65%,
compared with 30%-35% for
traditional heat engines. In addi-
tion, they are scalable and can be
applied to a wide range of mod-
ern lifestyle devices and needs,
including cars, mobile phones,
computers and buildings.
The main problem with alco-
hol fuel cells has been low power
density, the amount of power pro-
duced in relation to the volume
of the cell. Based on his seminal
work on the underlying mecha-
RACE FOR RENEWABLES
How a vanadium redox flow battery works.
Coupling of heat and mass transfer with
electrochemistry.
PROF TIANSHOU ZHAO
Chair Professor of Mechanical and Aerospace
Engineering, and Director, HKUST Energy Institute
My dream is a net zero energy
community, where all energy
is self sustainable
nism of couple heat/mass energy transfer
and electrochemical kinetics in fuel cells,
Prof Zhao discovered that the issue lay in
integrating the understanding of heat and
mass transport, and electrochemistry.
With such insight, a new theoretical
framework was developed, which led to a
dramatic increase in the performance of
direct methanol fuel cells by six times and
that of direct ethanol fuel cells by four
times. Prof Zhao has demonstrated a pro-
totype model car that can run for 10 hours
on 5cc of alcohol fuel. And an MP3 player
that plays for 20 hours on 2cc of fuel.
The researchers have also discovered
that hydrogen can evolve spontaneously
from a direct methanol fuel cell. This has
given rise to a new technique for hydrogen
production at room temperature minus
the carbon monoxide species common to
traditional methanol reformation.
Such theory and discoveries have
helped Prof Zhao’s research group to
tackle further related issues through
electrode design improvements for large-
scale redox flow battery technologies
that can help solve the “intermittent gen-
eration” problem for renewables such as
solar and wind by raising power density.
In contrast to solid state batteries that
integrate energy storage and power pack
together, a flow battery separates the
storage component from the power pack,
meaning that power and capacity can
be independently sized and making the
technology scalable. The battery lifespan
is also increased.
Prof Zhao’s unusual blend of
electrochemistry and thermo-
fluid science is indicative of the
non-traditional approach en-
couraged by HKUST. His team
comprises expertise ranging from
materials and modeling to fluid
sciences and electro-chemistry.
He also steers the HKUST Energy
Institute, launched in 2014 and
now serving as the platform
for the University’s multidisci-
plinary research into energy gen-
eration, storage, efficiency and
policy. Over 50 faculty members
across different departments
and Schools are involved in such
endeavors.
