IEEE Electrification Magazine - December 2017 - 4

VIEWPOINT

Powering Commercial Aircraft: The Next
Logical Step in Vehicle Electrification
By Waleed Said

HROUGHOUT THE HISTOry of aviation, the demand
for more electrical power
has never wavered. In the early days,
alternators driven by conventional
piston or jet engines began powering
radios and lighting cockpit instrument panels. Advances in aircraft
electrical systems slowly but surely
turned to fly-by-wire, doing away
with mechanical flight control in
favor of computers and circuitry.
More recently, power by wire has
electrified certain pneumatic and
hydraulic loads. This evolution has
continued with the Boeing 787's nobleed architecture concept, where
megawatt-level electrical systems
replace pneumatic power ones. It is
becoming more common for commercial airplanes to have large loads
driven by motors and associated
power convertors that range from a
single kilowatt to greater than 100
kW. This remarkable progression
over the last several decades points
to the next logical step in electric
power utilization on airplanes, i.e.,
to propulsion.
Although challenges remain on
the journey toward propelling aircraft with electricity, these are largely surmountable in the near future.
Improved electrification is the zeitgeist, with unprecedented investment
currently across personal electronics, ground-electric vehicles, smart
grids, renewables, and grid storage.

Digital Object Identifier 10.1109/MELE.2017.2755239
Date of publication: 26 December 2017

According to Goldman Sachs in 2016,
"Solar, onshore wind, and electric
vehicles will maintain momentum
and are now as much a transformative technology shift as they are a
regulatory response to global environmental challenges...Global coal consumption has already peaked, and
sales of pure combustion engine cars
could peak by 2020." This investment
is, in turn, driving the rapid development of key component technologies,
such as batteries, supercapacitors,
electric drives, power electronics, and
fuel cells. In other words, much of the
innovation necessary for electric
flight is arriving from the ground up.
The onus on the aviation sector is to
adapt those technologies to operation
at altitude.
The most powerful pathway,
pitfalls and all, is from electrified
ground vehicles. Increasing urgency
to address climate change is driving
jurisdictions to aggressive targets,
even phasing out gasoline vehicle
sales altogether, which is scheduled
to happen in Norway by 2025, in
India by 2030, and in France by 2040.
In line with this trend, the demand
for rechargeable lithium-ion batteries
has been forecasted to grow almost
sevenfold from 58 GWh in 2015 to
387 GWh in 2025, according to Goldman Sachs. Battery pack costs have
plummeted from US$680/kWh in
2010 to less than US$150/kWh last
year. According to Bloomberg New
Energy Finance research, released last
year, these falling costs are set to
make unsubsidized electric vehicles

IE E E E l e c t r i f i c ati o n M a gaz ine / DECEMBER 2017

more affordable than traditional gasoline vehicles as soon as 2022. This
outlook is likely to be exceeded, given
that Tesla has targeted US$100/kWh
for 2020 and General Motors aims for
the same by 2022.
The U.S. Department of Energy is
similarly bullish on the batteries
achieving an ever-increasing energy density at markedly decreasing
costs (Figure 1).
Just as with electric vehicles, for
electric propulsion to enter mainstream aviation, a sweet spot must
be found between the often-competing demands of technology and economics. Harkening back to the late
1990s, the initial introduction of electric cars was impeded by low reliability paired with high costs. These
stemmed from an immaturity of the
key technologies, such as batteries,
and were exacerbated by the need to
redo manufacturing processes honed
over generations of mass-market
automobiles. Major manufacturers
scaled back plans for all-electric vehicles, although hybrids persisted. Fast
forward to today, manufacturers are
vying to announce hybrids and electrics across their portfolios, where
the sector is squarely past the tipping
point. The success of electrically propelled airplanes may hinge on aviation adapting lessons learned by
the automobile industry to the aerospace environment.
Naturally, electrification technologies and their effectiveness vary significantly by the range and energy
intensity of the transport application.

Table of Contents for the Digital Edition of IEEE Electrification Magazine - December 2017