IEEE Electrification - December 2021 - 66

TABLE 2. An assessment of the two main hyperloop concepts.
Concepts
Energy-Autonomous Capsule With a Scalable
Low-Infrastructure Tube
Tube Infrastructure
Capsule weight
Range limitation
Acceleration
limitation
Capsule is self-propelled-it is the best option
in terms of affordability, using of few active
components
High-energy storage for onboard propulsion
with or without contactless power transmission
Depends on the onboard energy reservoir or
the feasibility of a wireless power supply while
moving
Power and energy allocated for acceleration affects
the range even if regenerative braking
under deacceleration is achieved
takes into account the low pressure inside the tube to
potentially maximize the power transmission efficiency.
Currently, one of the most difficult issues to solve for
the self-propelled system is the management of the heat
losses on board. The linear induction motor's efficiency
could be as low as 70% during cruising, which implies that
a significant portion of the inverter rating will feed losses
(Nøland 2021). The white paper from 2013 proposed an
onboard water tank to absorb all of the waste heat and
replace the water when it arrives at the station. Unfortunately,
this type of solution will add to the total mass of
the capsule. It is also difficult to throw heat waste out of
the capsule and into the tube because of the lack of air
density. As a result of the lack of air, the convective heat
transfer is significantly reduced, and the radiation part is
dominating. A summary of the two key concepts of external
and self-propulsion is provided in Table 2.
Conclusion
This article introduced some of the most recent technology
evolutions of the HTS, intended to make it feasible, scalable,
and affordable for implementation. In particular, it can be
perceived that the external propulsion enables a lightweight
capsule and might have a faster technical development track
to realization and commercialization. However, a self-propelled
capsule configured like an airplane requires less track
infrastructure and utilizes its active components during the
whole journey. While its low construction costs would significantly
improve the system's profitability and reduce the
maintenance of the operated infrastructure, the capsule
tends to get heavy when considering the onboard energy
storage and thermal management system. Therefore, companies
are now considering a hybrid solution, combining
external launching and self-propelled cruising, which balances
the benefits and drawbacks of both variants.
In addition to the technical challenges and opportunities,
there are also societal changes and policy decisions that
might play a role in speeding up hyperloop implementation.
There is currently a push to ban short-haul domestic flights
66
IEEE Electrification Magazine / DECEMBER 2021
Large-Scale Tube Electrification With a
Lightweight and Externally Driven Capsule
Active rails with significant infrastructure cost,
where active components are only utilized during a
tiny fraction of the ride
Low-lightweight capsule with only onboard auxiliary
energy (e.g., for controlling suspension)
Unlimited, as the propulsion is external but high
investments and the resource intensity favor short
range
Acceleration power can be high and the distance
needed for acceleration can be low but creates power
spikes for the grid
in Europe to accelerate the decarbonization of transport. An
alternative to rail is introducing hyperloop, which has the
potential to significantly decrease the energy use per RPK
when compared to aviation, and at the same time, move
with similar or higher travel speed. Still, no full-scale HTS
has yet been demonstrated at subsonic or near-sonic
speeds. However, this article tries to give more insight into
where the development is going and make predictions on
the future realization of this new mode of transportation.
For Further Reading
Communication from the Commission to the European Parliament,
the Council, the European Economic and Social Committee
and the Committee of the Regions, " Sustainable and
Smart Mobility Strategy-putting European transport on track
for the future, " European Commission, Brussels, Belgium, Dec.
9, 2020. [Online]. Available: https://ec.europa.eu/transport/
sites/transport/files/legislation/com20200789.pdf
J. K. Nøland, " Prospects and challenges of the hyperloop
transportation system: A systematic technology review, " IEEE
Access, vol. 9, pp. 28,439-28,458, Feb. 2021. doi: 10.1109/
ACCESS.2021.3057788.
E. C. Goddard, " Vacuum tube transportation system " , U.S.
Patent 2 511 979, June 1950.
E. Musk, " Hyperloop alpha, " Hawthorne, CA, White Paper,
2013. [Online]. Available: https://www.tesla.com/sites/default/
files/blog_images/hyperloop-alpha.pdf
D. Tudor and M. Paolone, " Optimal design of the propulsion
system of a hyperloop capsule, " IEEE Trans. Transport. Electrific.,
vol. 5, no. 4, pp. 1406-1418, Dec. 2019. doi: 10.1109/
TTE.2019.2952075.
A. Tbaileh et al., " Modeling and impact of hyperloop technology
on the electricity grid, " IEEE Trans. Power Syst., vol. 99,
pp. 3938-3947, Mar. 2021. doi: 10.1109/TPWRS.2021.3056298.
R. F. Post, " Maglev: A new approach, " Sci. Amer., vol. 282, no.
1, pp. 82-87, Jan. 2000.
Biography
Jonas Kristiansen Nøland (jonas.k.noland@ntnu.no) is
with the Department of Electric Power Engineering at the
Norwegian University of Science and Technology, Trondheim,
7491, Norway.
https://ec.europa.eu/transport/ sites/transport/files/legislation/com20200789.pdf https://ec.europa.eu/transport/ sites/transport/files/legislation/com20200789.pdf https://www.tesla.com/sites/default/files/blog_images/hyperloop-alpha.pdf https://www.tesla.com/sites/default/files/blog_images/hyperloop-alpha.pdf
IEEE Electrification - December 2021

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