新能源汽车外文文献翻译

新能源汽车外文文献翻译

文献出处

：

Moriarty P, Honnery D. The prospects for global green car mobility[J]. Journal of

Cleaner Production, 2008, 16(16): 1717-1726.

原文

The prospects for global green car mobility

Patrick Moriarty, Damon Honnery

Abstract

The quest for green car mobility faces two major challenges: air pollution from

exhaust emissions and global climate change from greenhouse gas emissions. Vehicle

air pollution emissions are being successfully tackled in many countries by technical

solutions

such

as

low- sulphur

fuels,

unleaded

petrol

and

three- way

catalytic

converters. Many researchers advocate a similar approach for overcoming transport's

climate

change

impacts.

This

study

argues

that

finding

a

technical

solution

for

this

problem is not possible. Instead, the world will have to move to an alternative surface

transport system involving far lower levels of motorised travel.

Keywords

：

Green

mobility;

Fuel

efficiency;

Alternative

fuels;

Global

climate

change; air pollution

1. Introduction

Provision of environmentally sustainable (or green) private transport throughout

the world faces two main challenges. The first is urban and even regional air pollution,

particularly in

the rapidly

growing cities of the industrialising world.

The second is

global

climate

change,

caused

mainly

by

rising

concentrations

of

greenhouse

gases

(GHGs) in the atmosphere. These two barriers to green car mobility differ in several

important ways. First, road traffic air pollution problems are more localised, because

of

the

short

atmospheric

lifetimes

of

most

vehicle

pollutants and .

Thus

regional

solutions are often not only possible, but also essential

–

Australian cities, for example,

can

(and

must)

solve

their

air

pollution

problems

themselves.

Matters

are

very

different

for

global

climate

change.

Except

possibly

for

geo- engineering

measures

新能源汽车外文文献翻译

such

as

placing

large

quantities

of

sulphate

aerosols

in

the

lower

stratosphere

or

erecting huge reflecting mirrors in space, one country cannot solve this problem alone.

Climate change is a global problem. Nevertheless, it is possible for some countries to

‘freeload’ if the majority of nations that are important GHG emitter

。

Second,

there

is

agreement

that

air

pollution,

especially

in

urban

areas,

is

potentially a serious health hazard, and that road transport can contribute greatly to

urban pollutant level. For these reasons,

governments in many countries are already

taking

effective

action

on

air

pollution.

But

until

recently,

climate

change

was

not

recognized as a major problem by some key policy makers, and all countries have yet

to take effective action on reducing emissions.

Third, vehicular air pollutant problems, at least in the Organisation for Economic

Cooperation

and

Development

(OECD)

countries,

are

already

showing

themselves

amenable to

various technical

solutions,

such as low-sulphur fuels,

unleaded petrol,

and

three-way

catalytic

converters.

Some

researchers

have

argued

explicitly

that

global transport emissions can be reduced to very low levels with a combination of

two

key

technical

solutions

–

large

improvements

in

vehicle

fuel

efficiency

and

a

switch

to

alternative

transport

fuels,

such

as

liquid

biofuels

and

hydrogen

derived

from

renewable

energy.

A

much

larger

group

implicitly

support

this

position

by

projecting

large

future

increases

in

car

numbers

and

travel

and

even

a

globally

interconnected highway system.

Further,

governments

throughout

the

world

have

endorsed

the

United

Nations

Framework Convention on Climate Change (which came into effect in 1994), but at

the same time are expanding their road networks, encouraging their car industry, and

planning for future car traffic expansion. Overall, the majority of both researchers and

policy

makers

appear

to

consider

that

climate

change

poses

no

threat

to

global

car

mobility.

Nevertheless,

other

researchers

argue

in

general

that

technology

cannot

solve the serious environment/resource problems the world faces global warming in

particular.

Also,

the

authors

themselves

have

earlier

questioned

whether

the

current

global

transport

system

can

continue

on

its

present

course.

This

paper

attempts

to

resolve these competing claims.

新能源汽车外文文献翻译

Transport,

of

course,

is

not

the

only

source

of

either

air

pollution

or

global

climate change. All energy-using sectors, and even land-use changes, can contribute

to

these

two

problems.

It

is

thus

important

that

any

attempts

to

reduce

transport's

emissions do not compromise similar efforts in other sectors of the economy. It is also

possible

that

emission

reduction

policies

in

one

country

could

adversely

affect

reduction efforts elsewhere.

The aim of this paper is to show that private car travel cannot form the basis for a

sustainable global system of surface passenger travel. To simplify the analysis, only

GHG

emissions

will

be

analysed.

We

argue

that

the

risk

of

global

climate

change

requires

effective

reductions

in

the

next

two

decades

or

so,

whereas

technical

solutions to drastically cut car travel's greenhouse gas emissions are only possible in a

much

longer

time

frame,

and,

in

some

cases,

possibly

not

even

then.

Overall,

the

world

will

have

to

rely

on

alternative

modes

(various

forms

of

public

transport,

walking and cycling), and, for much of the industrialised world, much-reduced levels

of personal travel as well. Of course, it is quite possible that the limited time frame

available

is

also

much

too

short

for

travel

reductions

and

modal

shifts

of

the

magnitude proposed here. The conclusions of this paper have relevance for freight and

air transport, and also for other sectors of the economy faced with the need for deep

cuts in GHG emissions.

2. Global climate change and global car travel

The

vast

majority

of

climate

scientists

support

the

view

that

emissions

of

heat-trapping

gases

into

the

atmosphere,

particularly

CO2,

from

fossil

fuel

combustion

and

land-use

changes,

cause

global

warming

by

altering

the

earth's

radiation

balance.

The

2007

report

from

the

Intergovernmental

Panel

on

Climate

Change

(IPCC)

states

that

sea

levels

are

rising,

glaciers

and

sea

ice

cover

are

diminishing,

and

11

of

the

12

warmest

years

since

1850

have

occurred

in

the

1995

–

2006

period.

Their

latest

estimate

(with

a

probability

of

66%

or

greater)

for

climate sensitivity

–

the equilibrium increase in global temperature resulting from a

doubling of CO2 in the atmosphere

–

is from 2.0 °

C to 4.5 °

C, with a best estimate of

3.0 °

C . Atmospheric CO2 concentrations are currently rising by some two parts per

新能源汽车外文文献翻译

million (ppm) annually.

Moreover,

large

positive

feedback

effects

could

result

in

emissions,

and

thus

temperatures, rising much more rapidly than expected on the basis of present fuel and

land-use

emission

releases.

One

such

feedback

is

large-scale

methane

release

from

northern

tundra

as

permafrost

melts.

There

is

some

preliminary

evidence

that

this

process

is

already

underway and.

Further,

studies

of

past

climate

have

shown

that

abrupt climatic change can occur over the course of a decade or even a few years and .

James

Hansen,

a

prominent

US

climate

scientist,

has

argued

on

the

basis

of

paleoclimatic

data

that

if

further

global

warming

is

not

limited

to

1 °

C

beyond

the

year

2000

value,

feedbacks

could

add

to

business-as-usual

emissions,

making

the

world

a

‘different

planet’.

His

1

°

C

rise

above

the

year

2000

figure

is

only

slightly

below

the

EU

value

of

2 °

C

above

the

pre-industrial

value,

given

the

estimated

0.74 °

C

warming

that

has

occurred

since

1880.

He

concludes

that

we

can

only

continue

present

trends

for

GHG

emissions

for

another

decade

or

so

before

committing the climate to irreversible change. Here, we take a position intermediate

between

den

Elzen

and

Meinshausen

and

Hansen,

and

assume

that

by

2030

global

emissions of both CO2 and other GHGs must be reduced to 25% their current value

–

a four-fold reduction in current global emissions.

Thus, to limit dangerous climatic change, annual emissions to the atmosphere

of

CO2

and

other

greenhouse

gases

will

need

to

be

greatly

curtailed,

unless

geo-engineering or carbon sequestration techniques can be successfully

deployed in

time. Equal

emissions per capita for all countries, as advocated by ‘contraction and

convergence’

proponents

,

are

likely

to

be

the

only

acceptable

proposal,

since

it

is

improbable

that

industrialising

countries

such

as

China

or

India

will

permanently

accept

lower

per

capita

emissions

than

the

already

industrialised

countries.

They

could go further, and demand parity in cumulative per capita emissions over the past

century

for

CO2,

a

long-lived

gas.

Such

an

approach

would

require

the

already

industrialised

countries

to

reduce

emissions

to

near

zero.

In

2003,

global

CO2

emissions from

fossil fuels

averaged 4.2 t/capita, but

varied widely

from country to

country. The US, Australian and Japanese emissions were, respectively, 4.8, 4.3 and

新能源汽车外文文献翻译

2.2 times larger than the world average, implying reduction factors of roughly 19, 17

and 9. (The US

reduction value of 19 by 2030 can be compared with

Huesemann's

calculated value of 66, although his

reduction is

for 2050.) Although many tropical

African

countries

emitted

less

than

5%

of

the

average

global

value,

most

of

the

industrialising world would also need to reduce emissions. In the absence of reliable

national data, we assume here that other GHG emissions for each country follow the

same pattern as fossil fuel CO2 emissions.

What

are

the

implications

for

transport,

and

private

car

travel

in

particular,

of

these

proposed

reductions

in

GHG

emissions?

Transport

contributed

an

estimated

19% of global GHG emissions in 1971, but 25% in 2006. In 2003, there were roughly

715

million

cars

in

the

world

(including

light

commercial

vehicles

in

the

US),

and

6270

million

people,

for

an

average

car

ownership

of

114/1000

persons and .

But

when

considered

at

the

national

level,

ownership

is

far

from

normally

distributed.

Although

the

global

average

is

114/1000

persons,

only

about

18.5%

of

the

world

population lived in countries with between 20 and 200 cars/1000 persons. A further

65% lived in countries with less than 20 cars/1000 (including China and India), and

the

remaining

16.5%

in

countries

with

greater

–

usually

far

greater

–

than

200

cars/1000.

Clearly, car ownership is presently heavily polarised; people either live in highly

motorised countries

–

usually in the OECD

–

or in countries with very low levels of

car

ownership.

But

the

picture

is

changing.

People

in

all

countries,

but

particularly

those in Asia, want to own a car; indeed, Asia reportedly leads the world in aspirations

for car ownership . Where incomes are rising rapidly, as in populous China and India,

so too are car sales and ownership. In 2006, China, with sales of 4.1 million, became

the world's third largest market for cars, overtaking Germany (3.4 million cars sold).

By 2010 it is

forecast

that China will move into second place ahead of

Japan, with

only

the

US

ahead.

India

sold

1.0

million

cars

in

2006,

and

annual

sales

are

rising

rapidly there as well. Despite urban congestion problems, these countries see vehicle

manufacture

as

an

important

part

of

their

industrialisation

programs,

and

the

major

world

car

companies

are

investing

heavily

in

new

Asian

production.

In

brief,

these

新能源汽车外文文献翻译

countries and others want to shift their societies from the low to the high motorisation

group.

What if the whole world moved to the high car ownership group? In the OECD

countries, car ownership averages over 450 cars/1000 and , and even in with 500 or

more

cars/1000,

is

still

growing.

In

the

US,

light

vehicle

ownership

at

777/1000

residents

in

2004,

was

15%

larger

than

the

licensed

driver

population.

Global

car

passenger-km (p-km) in any year is a product of the following three factors:

For 2030, the UN median projection for world population is 8.20 billion, and for

2050,

9.08

billion.

Assume

car

ownership

per

1000

world

population

reached

an

average of 300 in 2030 (which would allow most presently non-motorised countries to

attain

a

basic

automobility

level

of

200

cars/1000

persons),

and

that

the

present

average p-km/car remains unchanged. World cars would then total 2.46 billion. This

projected 2030 value for both total cars and global car p-km is 3.44 times the present

world total. Unless fuel efficiency and/or the fuels used change, GHG emissions (and

oil consumption) would rise similarly.

But,

as

we have argued, total

emissions

may

well have to be reduced four-fold. Assuming that percentage reductions in car travel

emissions must match overall reductions, emissions per car p-km would need to fall

about 14-fold by 2030 compared with their present value. The exact value would of

course

vary

from

country

to

country:

for

the

US,

Australia

and

Japan,

reduction

factors would be 23.6, 22.0 and 8.6, respectively, conservatively assuming no further

rise in car numbers in these countries and . Reduction factors would also be high for

countries

with

very

low

car

ownership,

but

in

this

case

the

reductions

refer

to

aspirations,

not

actual

travel

or

emissions.

The

next

two

sections

examine

whether

such reductions are possible in the requisite time frame.

3. Greening car mobility: more passenger-km per unit of fuel energy

For GHG emission reductions, the aim is to maximise travel for a given level of

CO2-e emissions. Thus, p-km/kg CO2-e is to be maximised for the global car fleet.

This ratio in turn can be expanded into the product of the following three factors:

This

section

deals

with

occupancy

rates

and

fuel

efficiency,

which

together

enable personal travel per MJ of fuel to be increased. The following section examines

新能源汽车外文文献翻译

ways of lowering GHG emissions by using alternative fuels, usually with new power

systems.

In

such

analyses,

it

is

important

to

distinguish

between,

on

the

one

hand,

voluntary change, or politically feasible mandated changes under normal conditions,

and

on

the

other,

changes

due

to

what

climatologists

in

a

different

context

term

‘external

forcing’

–

for

example

changes

brought

about

by

declining

global

oil

production, or by governments being required to meet serious GHG reduction targets.

3.1. Improving occupancy rates

Improving vehicle occupancy has an important advantage: in principle it can be

implemented

very

rapidly

with

the

existing

vehicle

fleet.

The

potential

efficiency

gains are also large. For a typical five-seat car, occupancy rates have effective lower

and

upper

limits

of

20%

(driver

only,

equivalent

to

1.0 p-km/v-km)

and

100%

(all

seats occupied), respectively, but actual overall values in the highly motorised OECD

countries seem to fall in the 25

–

35% range (1.25

–

1.75 p-km/v-km).

3.2. Improving fuel efficiency

Improving the energy efficiency of cars is often seen as a means of addressing

not

only

greenhouse

gas

emissions,

but

also

air

pollution

and

global

oil

depletion/supply

security.

Two

general

approaches

are

possible.

The

first

is

to

decrease

the

road

load

–

the

sum

of

rolling,

inertial,

and

air

resistance

–

a

general

approach that will be needed by all future vehicles, whether private or public transport.

Reducing

the

mass

of

the

vehicle

by

using

lighter

weight

materials

is

the

most

important means of decreasing the road load. The second is to improve the share of

input

energy

that

drives

the

wheels.

Electric

drive

is

today

regarded

as

the

best

approach for achieving this aim, mainly because it enables regenerative braking and

eliminates idling.

4. Greening car mobility: lower emissions per unit of fuel energy

One way around the difficulty of raising vehicle efficiency is to move away from

petroleum-based

fuels

to

fuels

with

a

lower

GHG

emissions

impact.

A

variety

of

alternative fuels systems have been advocated for road transport as a way of cutting

GHG

emissions.

These

include

various

biomass-based

fuels

for

internal

combustion-engined vehicles, and use of renewable energy to produce hydrogen for

新能源汽车外文文献翻译

fuel cell vehicles or electricity for plug-in hybrids and pure battery electric vehicles.

LPG

and

compressed

natural

gas

are

also

presently

used

alternatives

to

petrol

and

diesel,

but

are

themselves

hydrocarbon

fuels

in

limited

supply,

and

their

emission

reduction

benefits

over

petrol

are

minor

and .

Synthetic

fuels

made

from

more

abundant coal reserves would double the GHG penalty. Accordingly, this section first

looks

at

biomass-based

liquid

fuels

for

existing

vehicle

types,

then

at

various

renewable energy options for alternative propulsion system vehicles.

At present, the only transport biofuels produced in quantity are ethanol, chiefly

in

US

and

Brazil,

but

also

in

an

increasing

number

of

other

countries,

including

Australia, and biodiesel, produced mainly in the European Union (EU).

The large US and Brazilian ethanol programs are based on corn and sugarcane,

respectively, the EU's biodiesel on rapeseed oil. All are food crops, which limit their

expansion

in

a

world

with

unmet

food

needs,

and

a

still-growing

population

and .

Already, corn prices have risen steeply, as growers can now sell their corn in either the

food or fuel markets. Furthermore, at least for grain ethanol, both in the US and in the

EU, the fossil fuel energy inputs are, at best, not much below the energy content of the

resulting liquid fuel.

Initial enthusiasm for pure battery electric vehicles faded when the difficulty of

matching the range of internal combustion vehicles became apparent. The new focus

is on rechargeable battery hybrid vehicles (often called plug-in hybrids), building on

the

sales

success

of

hybrid

cars and.

Plug-in

hybrids

would

normally

run

off

an

electric

motor

powered

from

rechargeable

batteries,

but

could

also

run

on

petrol

or

other liquid fuels from their small conventional engines, thus extending their range.

Car companies in recent years have also shown much interest in hydrogen fuel

cell vehicles. But a number of studies have shown that when mains electricity is the

primary

energy

source

for

both

plug-in

hybrid

vehicles

and

hydrogen

fuel

cell

vehicles, plug-in hybrids are far more energy-efficient. Specifically, when a given car

model

is

a

plug-in

battery

hybrid

vehicle,

running

off

its

battery,

its

well-to-wheels

energy efficiency will be up to four times higher than when powered by a hydrogen

fuel cell, with the hydrogen produced by electrolysis of water, and . GHG emissions