Simulado Banco do Brasil (BB) | Escriturário | 2019 pre-edital | Questão 277

Língua Inglesa / Elementos Gramaticais

Natural gas waits for its moment

Paul Stenquist Cars and trucks powered by natural gas make up
a significant portion of the vehicle fleet in many parts
of the world. Iran has more than two million natural gas
vehicles on the road. As of 2009, Argentina had more
than 1.8 million in operation and almost 2,000 natural
gas filling stations. Brazil was not far behind. Italy and
Germany have substantial natural gas vehicle fleets.
Is America next?
With natural gas in plentiful supply at bargain
prices in the United States, issues that have limited its
use in cars are being rethought, and its market share
could increase, perhaps substantially.
According to Energy Department Price
Information from July, natural gas offers economic
advantages over gasoline and diesel fuels. If a
gasoline-engine vehicle can take you 40 miles on
one gallon, the same vehicle running on compressed
natural gas can do it for about $1.50 less at today’s
prices. To that savings add lower maintenance costs.
A study of New York City cabs running on natural
gas found that oil changes need not be as frequent
because of the clean burn of the fuel, and exhaust-
system parts last longer because natural gas is less
corrosive than other fuels.
Today, those economic benefits are nullified by
the initial cost of a natural gas vehicle — 20 to 30
percent more than a comparable gasoline-engine
vehicle. But were production to increase significantly,
economies of scale would bring prices down. In an
interview by phone, Jon Coleman, fleet sustainability
manager at the Ford Motor Company, said that given
sufficient volume, the selling price of natural gas
vehicles could be comparable to that of conventional
It may be years before the economic benefits
of natural gas vehicles can be realized, but the
environmental benefits appear to be immediate.
According to the Energy Department’s website, natural
gas vehicles have smaller carbon footprints than
gasoline or diesel automobiles, even when taking into
account the natural gas production process, which
releases carbon-rich methane into the atmosphere.
The United States government appears to favor
natural gas as a motor vehicle fuel. To promote the
production of vehicles with fewer carbon emissions, it
has allowed automakers to count certain vehicle types
more than once when calculating their Corporate
Average Fuel Economy, under regulations mandating
a fleet average of 54.5 miles per gallon by 2025.
Plug-in hybrids and natural gas vehicles can be
counted 1.6 times under the CAFE standards, and
electric vehicles can be counted twice.
Adapting natural gas as a vehicle fuel introduces
engineering challenges. While the fuel burns clean, it
is less energy dense than gasoline, so if it is burned
in an engine designed to run on conventional fuel,
performance and efficiency are degraded.
But since natural gas has an octane rating of 130,
compared with 93 for the best gasoline, an engine
designed for it can run with very high cylinder pressure,
which would cause a regular gasoline engine to knock
from premature ignition. More cylinder pressure yields
more power, and thus the energy-density advantage
of gasoline can be nullified.[...]
Until the pressurized fuel tanks of natural gas
vehicles can be easily and quickly refueled, the fleet
cannot grow substantially. The number of commercial
refueling stations for compressed natural gas has been
increasing at a rate of 16 percent yearly, the Energy
Department says. And, while the total is still small,
advances in refueling equipment should increase
the rate of expansion. Much of the infrastructure is
already in place: America has millions of miles of
natural gas pipeline. Connecting that network to
refueling equipment is not difficult.
Although commercial refueling stations will be
necessary to support a substantial fleet of natural gas
vehicles, home refueling may be the magic bullet that
makes the vehicles practical. Electric vehicles depend
largely on home charging and most have less than half
the range of a fully fueled natural gas vehicle. Some
compressed natural gas home refueling products are
available, but they can cost as much as $5,000.
Seeking to change that, the Energy Department
has awarded grants to a number of companies in an
effort to develop affordable home-refueling equipment.
[...] Available at: <
Retrieved on: Sept 3rd, 2014. Adapted.

The modal verb may in the fragment of the text “It may be years before the economic benefits of natural gas vehicles can be realized” (lines 35-36) is associated with the idea of

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