8.2.2 Fuel Technology Improvements
Gasoline and diesel can be improved by chemical reformulation that can lead
to decrease in ozone-forming pollutants and carbon monoxide emissions per km
travelled, but will be greater for non-catalyst controlled vehicles (IEA/OECD,
1998). Performance problems, cold-start ability, smooth operation and avoidance
of vapour lock are disadvantages of using reformulated fuels. Alternative fuels
to petroleum include compressed natural gas (CNG); liquefied petroleum gas (LPG);
methanol from natural gas, coal or biomass; ethanol from biomass; electricity
and hydrogen. The use of these options in reducing GHGs will depend on ease
of use, performance and cost, however, CNG, LPG and ethanol are now used in
niche markets (high mileage and urban travel) in both developed and developing
countries (Sanwar et al., 1999). On a full-cycle basis, use of LPG can result
in 20-25% reduction in GHG emissions as compared to petrol, while emission benefits
from CNG are smaller - about 15%. Although CNG emits less CO than petrol, gains
from CNG depend on the amount of associated methane emissions from gas recovery,
transmission, distribution, and use. Life cycle GHG emissions from alcohol fuels,
such as methanol and ethanol, depend on the source and conversion technology
(DeLuchi, 1993; IEA, 1993). GHG emissions from methanol made from coal will
be double that of petrol, whereas methanol from natural gas will be the same,
and from wood will be lower. Ethanol from maize, wheat and sugar beet will result
in GHG emissions of 20-110% of that of petrol depending on fertiliser inputs
and fuel used for conversion. Ethanol from sugar yields 80% GHG emission benefits
in comparison to petrol, and almost 100% if baggase is used instead of coal
in conversion (Goldemberg and Macedo, 1994). The use of ethanol and CNG as transport
fuel is shown in Boxes 8.1 and 8.2.
Box 8.1 Compressed natural gas as
a transport fuel |
Compressed natural gas (CNG) can be an attractive alternative
transport fuel to gasoline because of its environmental benefits including
reduction of GHGs. It is more useful for countries with natural gas resources
and a relatively good gas distribution system. The use of CNG as a transport
fuel started in the 1930s but failed to increase its share because, as with
most alternatives, petroleum was a preferred fuel due to cost advantages.
However, the current threat of climate change has increased the focus on
alternative transport fuels including CNG. Countries with programmes on
the use of CNG as a transport fuel include the USA, Canada, UK, Thailand,
New Zealand, Argentina and Pakistan. CNG is used in both private vehicles
and transport fleets. It is estimated that about 250 million vehicles are
using this fuel worldwide, and its use is on the increase, representing
2% of total global transport fuel use. The advantages to using CNG, beyond
environmental ones, include reduced engine maintenance cost, and improved
engine and fuel efficiency. Disadvantages include power loss, limited range
of storage (100-150 km), and high cost of conversion. The environmental
benefits relating to climate change are given in the Table below: |
EMISSIONS |
CNG |
REG. GASOLINE |
SUPER GASOLINE |
DIESEL |
CO |
1 |
10.4 |
9.0 |
1.2 |
Unburned HC |
1 |
2.0 |
1.4 |
1.2 |
NOx |
1 |
1.2 |
1.4 |
1.1 |
Particulates |
neg. |
present |
present |
very high |
SO2 |
neg. |
neg. |
neg. |
very high |
Lead |
nil |
declining |
declining |
nil |
A case is given below to illustrate transfer of CNG technology
between Pakistan and New Zealand.
Pakistan has proven reserves of natural gas in excess of approximately 850
billion m3 (90% methane, sp. gr. of 0.56, and octane of 130). The country
embarked on using CNG as a transport fuel in 1980 with officials of the
Hydrocarbon Development Institute of Pakistan (HDIP) visiting Italy and
New Zealand for two years to gain experience with CNG technology. A pilot
phase was first introduced in 1982 in Karachi, and all the compressors and
conversion equipment was purchased in Italy and New Zealand. In 1992, the
government, through the Ministry of Petroleum and Natural Resources, promulgated
the CNG Rules of 1992 that have commercialised CNG as a transport fuel in
Pakistan. Six years later, 25 CNG stations became operational and another
25 were at various stages of completion. Along with the Rules of 1992, the
Gazette of Pakistan Extra of July 28, 1992 provided guidelines for the safe
practices of CNG relating to storage, filing and distribution. Under a UNDP/ESCAP
programme in 1991, HDIP in collaboration with Liquid Fuels Management Group
(LFMG) of New Zealand undertook a detailed six-month field test of completely
retrofitted buses, partially converted buses and diesel buses. The results
revealed that CNG is environmentally better, because it was lead free, had
no particulate matter, and very low smoke density, but the levels of CO
and NOx emitted were higher than that of diesel. It was found that CNG is
more economically and technically suitable for conversion from spark ignition
engines, but will require major modifications for high compression diesel
engines. Originally, all conversions were done in New Zealand, but now Pakistan
only receives kits from there and the conversions are done by local technicians.
Though the cost differential between CNG and gasoline is small, it is estimated
that about 25,000 gasoline vehicles have been converted to CNG. Source:
(Sarwar et al., 1999). |
Box 8.2 Ethanol as a transport fuel in developing
countries (Source: Goldemberg, and Macedo, 1994) |
Ethanol can be important in helping to reduce GHG emissions. The energy
derived from biomass, and in this case, from a renewable, "clean"
source, i.e., from sugar cane, has the unquestionable advantage of permitting
the almost complete re-absorption of CO2 emitted through the combustion
of ethanol. This closed cycle allows, in principle, to increase the global
energy supply, essential for sustained economic growth, without creating
hazards for the environment. The relevance of fuel alcohol in connection
with the global efforts for reducing CO2 emissions is singled out as one
of the major contributors to the reduction of the greenhouse effect. It
is important to note that, with technological advances and research, the
price of alcohol can be made competitive with gasoline in the long run,
but with the added advantage of providing a clean and renewable source
of energy.
Ethanol in Brazil
The National Alcohol Programme (PROALCOOL), launched in November 1975,
in Brazil, appeared to be the answer to the dangers of oil shortages.
The programme's objectives were to guarantee the steady supply of fuel
in the country; substitute a motor vehicle fuel from a renewable energy
source for imported gasoline; use the sugar cane production to its full
potential, especially in view of the drop in the world sugar prices; diminish
regional inequalities and promote greater rural employment; and to encourage
technological development in connection with the production of sugar cane
and alcohol.
The programme benefited from a combination of favourable circumstances:
the availability of adequate technology for the production of alcohol;
the ability of the sugar sector to adjust quickly to the production of
alcohol; the expansion of the distilleries; and the low international
price for sugar, due to the general crisis of the sector, in part caused
by overproduction.
Until 1979, the first phase of the Programme, alcohol production concentrated
on anhydrous alcohol (99.33% ethanol) for blending with gasoline. The
proportions of the mixtures varied. During this period, the programme
benefited greatly from the expanded installed capacity of the distilleries
annexed to the sugar mills. The second phase began with the second oil
crisis (1979), placing considerably more ambitious goals before PROALCOOL.
A change occurred, resulting in the predominance of hydrated alcohol,
used in pure form as car fuel. The car factories in Brazil began to design
vehicles using fuel alcohol exclusively. The industry appeared to welcome
the new fuel and invested in research and development of alcohol-run cars;
given the high oil prices, fuel alcohol would permit increasing production.
The first cars run solely on fuel alcohol were produced in 1979. By December
1984, the number of cars run on pure hydrated alcohol reached 1,800,000,
i.e., 17% of the country's car fleet.
Fuel alcohol is a "clean" fuel because the local effects of
gas emissions are less damaging to the environment, generally speaking.
On the average, alcohol-run vehicles emit less carbon monoxide, hydrocarbons
and sulphur. Another advantage of alcohol over gasoline is that alcohol
replaces tetraethyl lead, which is hazardous to health and the environment,
and is used as an additive to increase gasoline octane level. In fact,
in the United States, alcohol is added to gasoline to diminish the high
index of environmental pollution.
Ethanol in Zimbabwe
Zimbabwe, in Southern Africa, also operates an ethanol plant that was
locally planned and is producing 40 million litres annually. As a lot
of other developing countries, Zimbabwe had energy security problems in
the 1970s. Petroleum products accounted for 14% of energy consumption
and besides that the country was an exporter of sugar. At that time the
international price of sugar was very low, so the conversion of sugar
to ethanol was both economic and strategic.
In 1975, The Triangle, a private enterprise, decided to use surplus molasses
from up to 40,000 tonnes of sugar for ethanol production and started production
in 1979. The German Company Gebr. Hermman supplied the plant design and
was willing to provide a "turn-key" project. The Zimbabwean
firm only purchased the plants (at a reduced price) while the German firm
supervised its activities. Adaptation was necessary and involved discarding
many automatic controls in favour of manual operation to suit the capabilities
of the local workforce. Local material was utilized up to 60%, substituting
stainless steel used in the distillation columns with approval of and
supervision by the German firm. The final cost was US$ 6.4 million for
a plant capable of 40 million litres a year.
The ethanol produced is sold to National Oil Corporation of Zimbabwe
and they resell it to various oil companies. Ethanol as a fuel with 13%
blend was the only petrol available for a long period in Zimbabwe, with
very few modifications. The plant has been operating for over 18 years
with a lot of environmental benefits, skill transfer and technological
adaptation as well.
|
Electric vehicles have the potential of having significant life-cycle GHG reductions
depending on the primary energy source; the vehicle technology and method of
use (DeLuchi, 1993; ETSU, 1994; Martin and Michaelis, 1992). Its widespread
use will depend on battery charge/discharge efficiencies at high current, motor
and controller efficiencies at high load, and improvements in vehicle design.
Also, electric powered systems can be costly and inflexible. Hydrogen is a clean
transport fuel but requires high energy input and has serious storage and cost
problems. Development of alternative aviation fuel, such as liquefied natural
gas (LNG) and liquid hydrogen, is going on and can result in up to 20% lower
carbon emissions than kerosene for LNG, but is not expected to be commercial
in the next 10 years. Details of alternative fuels are in Table 8.4.
Table 8.4 Technical and potential
transport fuel technologies |
TECHNOLOGY |
EXAMPLES |
STATUS |
TECHNICAL FEASIBILITY |
CONVERSION EFFICIENCY |
ENVIRONMENTAL IMPACT |
MARKET POTENTIAL TIME FRAME |
FUEL SUBSTITUTION |
|
|
|
|
|
|
1. Improved Gasoline and Diesel Fuel |
Reformulated gasoline
Reduced Reid vapour pressure (RVP)
|
Within current refining techniques |
Chemistry available
Refinery balance and the need to produce more light ends
|
<2% gain for vehicles
increase in refinery energy efficiency
|
Significant VOC reduction
Limitations on fuel additives
|
0-10 years |
2. Natural Gas and LPG |
On-board storage
System integration
|
Demonstration fleets
Field trials
Fuels commercially available
|
Range extension needed
System cost abatement
|
Close to gasoline with engine adaptation |
VOC, CO2 and particulate reduction |
0-15 years |
3. Alcohol Fuels (in an ICE) |
Neat methanol
Neat ethanol M85
|
Demonstration fleets
Field trials in large vehicles
Commercial availability of blends
|
Supply limitation and cost needs
Change in OEM design
Low-cost emissions control option
Multiple feedstocks
|
15% improvement |
VOC and CO2 reductions |
0-20 years |
4. Hydrogen (in an ICE) |
Neat H2 in ICE storage systems |
R&D and prototypes |
Renewable source of supply
Distillation & production hurdles
|
Dependent on feedstock and storage system |
Substantial reductions in all pollutants |
30 years |
Energy Regeneration |
Hydraulic and kinetic storage
Engine management and electric storage
|
R&D and prototypes
Large vehicles with electric trains
Demonstration bus fleets
|
Energy storage systems
Transmission of power requires availability of CVT to blend power
|
Dependent on mission profile but 15-20% improvement possible |
Reduction of all emissions in proportion to efficiency gain |
10-20 years |
Electric and Hybrid Vehicles |
Electric batteries
Fuel cells
Solar photovoltaic cells
Hybrid systems
|
Demonstration fleets
Field trials in niche markets
|
Range and cost limitations may limit market
Adopting hybrid drives may increase use options
|
Dependent on base fuel with 20-40% gain possible |
Reduction to zero of all vehicle emissions
Environmental benefit to be gauged against overall fuel cycle
|
10 years |
Recent increasing interest in the development of hybrid vehicles (combination
of gasoline engine and battery-motor system) is yielding positive results that
can have a positive impact on GHG reduction. Making optimum use of the different
power supply system to suit the demand, and with an engine switch-off system
during short breaks, up to 30% fuel efficiency gains can be achieved, as has
been shown for models by Mitsubishi and Toyota (Tsuchiya, 1997). However, there
are some disadvantages such as higher weight and slightly higher cost, but current
declining cost could assist its commercial success. Use of hybrid vehicles with
fuel cells and batteries is actively being considered by many manufacturers,
but the cost is still very high for commercial application and may be in market
early next century (OECD, 1997).
|