Examination
of Pure Plant Oil as a Transportation Biofuel – Experiences
and Potentials
Pure plant oils have been shown to offer great promise as
a transportation biofuel. A European Parliament report [3]
that examined biofuels before the biofuels directive was finalised
stated “Because of its non-toxic nature and its allowance
for smaller refining units, this approach would probably bring
the greatest long-term benefits in terms of regional development,
environmental balance and job creation.” However this
option is often discredited due to experiences when operating
plant oils in diesel engines. A growing number of studies
have examined its usage. Unfortunately the results of these
studies have been mixed largely due to variables in both fuel
characteristics and engine optimisation.
As an example the Department of Transport commissioned study
[1] cited in the consultation papers last summer would at
face value show that rapeseed oil fuelled cars have greater
emissions than vehicles fuelled with diesel fuel. Examination
of this study by someone with experience of the technologies
and issues involved shows that the equipment fitted and adjustments
made to the vehicles to allow rapeseed oil usage were not
sufficient to provide optimised operation. The rapeseed oil
used as a fuel was not tested to ensure that its properties
were suitable for use as a diesel engine fuel; some properties
of relevance were tested and found to be within levels considered
appropriate. Other important variables which would affect
combustion and reliability were not tested.
Emissions from the use of PPO have also been examined in
a recent literature review compiled on behalf of the Dutch
government [2]. This review examined a number of different
recent studies and drew the conclusion that when PPO tailpipe
emissions were compared to those of diesel fuel there were
no clear differences except for reduced NOx.
Also concerns about reliability in diesel engines are often
cited. However numerous properly converted vehicles have been
shown to operate reliably. German experiences have shown PPO
to be a viable alternative with many possible advantages over
alternatives [4]. In Germany a fuel standard has been created
by a partnership between industry and academia, the German
government is now looking at adopting this standard to further
promote developments. It has often been stated that if vehicle
manufacturers
were encouraged to produce vehicles with engines designed
to handle PPO that uptake would be encouraged due to the negation
of the expense of conversion. It has been calculated that
if engines were produced with PPO capability the costs would
be greatly reduced.
Support for PPO in the UK is limited and it appears the government
has received little in the way of solid information on the
prospects of this biofuel. This would appear to be largely
due to the lack of industry interest in this fuel; currently
there are a very limited number of small firms involved in
these technologies. The suggestion would be that the financial
incentives are insufficient to promote its usage despite possible
advantages over other options. There has also been much confusion
over the tax position of PPO which has slowed uptake.
Results of comparisons between different renewable alternatives
generally frame biodiesel (which shares many factors with
PPO production) using current intensive chemical heavy input
crop production and large scale mill oil extraction. These
variables could be significantly improved by the adoption
of less intensive crop production (eg. using organic farming
methods) and the use of small scale presses which have been
proven to be able to supply quality fuel with good overall
economic and environmental performance. This allows fuel transportation
to be greatly reduced as fuel can be grown and produced close
to point of use. Obviously this is a ‘best case scenario’
but these methods are growing in popularity both in Germany
and other EU member states. Cold pressed locally distributed
rapeseed fuel has been shown to have an energy balance of
24.85:1 and a CO2 balance of 14.44:1 [5].
There is also a large potential for the use of other oil
crops. Oil based biofuel production has concentrated on feed
stocks from readily available food oils. There are a huge
number of oil producing plants that could potentially provide
a suitable fuel oil and may well lend themselves to better
methods of cultivation and better yields; algae is often cited,
tree and shrub crops can produce high yields with reduced
cultivation inputs, mixed plantings of oilseed and other crops
have been shown to provide good yields.
[1] Dft Biofuels Evaluation – Final Report of Test Programme
to Evaluate Emissions Performance of Vegetable Oil Fuel on
Two Light Duty Diesel Vehicles http://www.dft.gov.uk/stellent/groups/dft_roads/documents/page/dft_roads_027622.pdf
[2] Compatibility of pure and blended biofuels with respect
to engine performance, durability and emissions - SenterNovem
http://www.novem.nl/default.asp?menuId=10&documentId=150024
[3] Report on the proposal for a Council directive amending
Directive 92/81/EEC with regard to the possibility of applying
a reduced rate of excise duty on certain mineral oils containing
biofuels and on biofuels(COM(2001) 547 . C5-0030/2002 . 2001/0266(CNS))
Committee on Economic and Monetary Affairs
[4] BioDiesel and Pure Plant Oil Examination of the Effects
of German Biofuel Uptake Prof. Dr. Ernst Schrimpff Fachhochschule
Weihenstephan University of Applied Sciences
[5] Note:Rapeseed Oil for Transport 1: Energy Balance and
CO2 Balance-Based on EMBIO, The Danish Energy Agency’s
Model for Economic and Enviromental Assessment of Biofuels
Jacob Bugge Folkcenter for Renewable Energy-Denmark2000
http://www.folkecenter.dk/plant-oil/publications/energy_co2_balance.pdf
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