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MINISTERIAL ECONOMIC
SUPPORT ON LPG AND METHANE FUELS USE IN AUTOTRACTION: TECHNICAL AND ECONOMICAL
FEASIBILITY OF A METHANE SERVICE STATION FOR PUBLIC TRANSPORT
Introduction
The National Decree of 22nd December, 2000, “Support to Municipalities on methane and LPG
fuels use in autotraction”, gives economic support to cities that convert
their conventional public
bus fleets (or those assigned to local public services) into
methane gas-fuelled ones - even if registered later than 1992 - and for
developing a network of methane gas service stations for public transport
fleets.
In May 2001 an Agreement Protocol between the
Environmental Ministry, Municipalities and Trade Associations was signed. The Municipality of Parma was nominated as the lead city in
the implementation of a national project committed to the coordination and
integration of the local management of low environmental impact fuels. This
initiative was called the ICBI (Low Environmental Impact Fuels Initiative).
More than 100 Italian municipalities expressed an interest
to the Environmental Ministry about taking part in the ICBI. Of these, 166 have
already completed the agreement approval process. the Municipality of Venice is one of them.
The aims of the agreement are as follows:
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structural
and permanent reduction of the impact of traffic in urban and metropolitan
areas;
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promotion
of fuels with low environmental impact, especially LPG and methane, through
vehicle-conversion programmes;
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development
of alternative-fuels service networks;
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implementation of policies and initiatives in favour of low
environmental impact fuels and development of
agreements at the national level with Ministries and LPG/methane Trade
Associations.
After its assent to the ICBI agreement, the city of Venice asked for financial support for
the implementation of a service station fuelled by methane in its territory.
The project aims to improve air quality in Venetian territory, where
atmospheric pollution has reached acute levels these the last years.
Methane service
station in the city of Venice-Mestre
The financial support asked by the city of Venice corresponds to the cost of
implementing a methane compression/distribution plant in order to supply 60
ACTV buses (ACTV - Venice Public Transport Company) in municipal territory.
The present bus fleet consists of 606 buses of varying age
and characteristics. In 3 years 60 buses will be methane-fuelled, reaching a
rate of renovation that is about (60/606) x 100 = 10 %. This programme will
help to substitute buses with an average age of more than 15 years or buses
with obsolete engines or a high number of kilometres. All these characteristics
can cause high levels of polluting emissions.
It is expected that the methane-fed fleet will gradually
grow over the three years as older buses are replaced. The rate at which
Methane buses will enter into service will be 34 the first year, 16 the second,
and 10 the third.
Overall investment for planning, technological components
and links to the general methane gas network is estimated at €940.000. Other supporting works and the marketing plan
are estimated in €45.000. Extra costs deriving from the purchase of 60
methane-fuelled buses is €2.100.000.
Reference data needed for planning activities has been
taken from ACTV data and evaluations on methane consumption:
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Average number of kilometres x
bus (km/day)
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250
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Maximum number of kilometres x bus (km/ day)
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300
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Average number of kilometres x GPL-fuelled bus
(km/litre)
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2,2
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Average number of kilometres x methane-fuelled bus
(km/Sm3)
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1,4
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Bus average gas consumption (Sm3/day)
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178
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Average number of kilometres x bus (km/year)
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75.000
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Bus average gas consumption (Sm3/year)
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53.571
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Scheduled time for refuelling
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22.00 – 06.00
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Alternative time for refuelling
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14.00 – 16.00
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Time needed to refuel 60 buses (hours)
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10
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Consumption is influenced by the category of bus, by its
speed and its loading factor. Those values have been estimated on the basis of
diesel oil consumption and by studying the situation of other Italian cities.
In Italian cities average gas consumption of urban buses 10/12 m long, is 1,4/1,5 km/m3 (minimum 1,2 km/m3 ,
maximum 1,7 km/m3). Knowing that traffic is slow especially in
central zones and rush hours the reference value recommended for Venice- Mestre
is 1,4 km/m3.
To estimate gas supplying capacity, the annual average
number of kilometres x bus has been calculated. As a result the annual average
consumption has been determined to be 53.571 Sm3 for each bus. Environmental
advantages, considering the number of kilometres run by buses, are absolutely
positive. In the hypothesis of replacing 60 buses, it would be possible to
reduce pollutant emissions by:
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124.000 kg of CO
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8.600 kg of HC
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172.000 kg of NOX
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8.000 kg of PM10
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