RENEWABLE ENERGY FOR CLEAN SUSTAINABLE TRANSPORT IN THE TOURISM SECTOR
Pat Bell, BE, MIEI
ENTRAC - Energy Transport Actions
85 Rail Park, Maynooth, Co. Kildare, Ireland
Tel/Fax: +353-1-6289329, Email: firstname.lastname@example.org
Jim O’Malley, BSc, CEng, MIMechE
ENTRAC - Energy Transport Actions
65 Heatherview, Sligo, Ireland
Tel/Fax: +353-71-61027, Email: email@example.com
Wilhelm Bodewigs, Dipl. Ing.
Sligo Town Centre Partnership
20 John Street, Sligo, Ireland
Tel/Fax: +353-71-50095, Email: firstname.lastname@example.org
Most European cities are experiencing ever growing traffic conditions leading to increasing problems of
congestion and emission levels with a consequent loss of quality of life. This is particularly true of tourist
destinations most of which suffer from seasonal peaks in their traffic levels. One of the most effective
ways of tackling this problem is to take an integrated approach of introducing more environmentally
friendly vehicles and simultaneously encouraging a modal shift from private transport to public transport.
Renewable energy for public transport can contribute on both fronts providing a sustainable, clean and
attractive alternative to the private car. This paper will review these renewable options, which fall into
two broad categories of biofuels and electric vehicles powered by renewable energy sources. The options
will be considered in the context of an ALTENER funded feasibility study undertaken in Sligo.
Sligo is a small city in the North West of Ireland with a population of 20,000 projected to double to
40,000 when the city is upgraded to a regional urban growth centre. Traffic congestion has already grown
rapidly in recent years and is set to continue in line with projected population, economic and tourist
growth. Public transport is underdeveloped. Sligo Corporation is urgently considering its approach to
these problems and is anxious to do so in a sustainable way. It co-operated with the Sligo Town Centre
Partnership to secure ALTENER funding to carry out a feasibility study into the use of renewable energy
for local public transport.
In particular, the study is focusing on using small-scale hydro-electricity from the Garavogue river which
runs through the city from Lough Gill. The electricity could be used to charge stationary battery
installations which in turn would be used as rapid recharge stations. An innovative flywheel powered
ultra-light tram will be considered, integrated with other forms of transport such as electrically assisted
transport, renewable energy, biofuels, hydro-electricity, electric vehicles, ultra-light tram, tourism, Sligo
ENTRAC is an engineering consultancy specialising in energy efficient and sustainable actions with
particular emphasis on transport. ENTRAC is experienced in carrying out investigations and evaluations
for national and local governments, large corporations and the European Commission to which it also
gives technical support.
1. SLIGO AS A TOURIST DESTINATION
One of the most effective ways of tackling this
Sligo is a small city in the North West of Ireland problem is to take an integrated approach of with a population of 20,000 projected to double to introducing more environmentally friendly vehicles 40,000 within 15 years when the city is upgraded to and simultaneously encouraging a modal shift from a regional urban growth centre. It is the focal point private to public transport. Renewable energy for of the region due to its geographic location and low public transport can contribute on both fronts density structures in regional habitation. The main providing a sustainable, clean and attractive traffic corridor is North-South due to the restrictions alternative. The renewable options considered fall of the Atlantic to the West, Lough Gill to the East into two the broad categories of biofuels and electric and the river Garavogue which, coincidentally, are vehicles powered by renewable energy sources . also major tourist attractions.
2.1 Biofuels This corridor links both the North and West of Biodiesel produced from vegetable oil is technically Ireland and also Northern Ireland with North West very feasible. In Ireland the most likely form would Ireland. A considerable amount of the traffic into the be rape methyl ester (RME) as rapeseed is the only area is related to tourism. The area is often referred oil crop commercially produced; sunflower oil is to as Yeats Country as it featured prominently in the more common in Southerly regions. Pilot projects poetry and writings of W.B. Yeats. Lough Gill, for indicated that it is particularly suited to tourist example, contains the famous “Lake Isle of applications. For example, a 12.8m cruiser used Innisfree”. County Sligo also contains one of the biodiesel for 6 months with no technical problems richest concentrations of prehistoric monuments in and two shuttle buses in a national park were also Western Europe. enthusiastically received. However, it was concluded
that biodiesel produced from rapeseed will remain Traffic congestion has grown rapidly in recent years too expensive in the near future and that, in addition, and is set to continue in line with projected the supply is too variable on the agricultural side . population, economic and tourist growth. Investment in transport infrastructure and public transport have not kept up with the pace of development. Sligo
Corporation is urgently considering its approach to these problems and is anxious to do so in a sustainable way and in co-operation with local business. With this objective it co-operated with the Sligo Town Centre Partnership to secure ALTENER funding to carry out a feasibility study into
sustainable solutions to the traffic problems . The
aims of the project are to: ? Examine the utilisation of renewable energy for local public transport ? Confirm that the river Garavogue is a suitable power source for such a transport system ? Create an example of excellence for new urban
Figure 1: Biodiesel fuelled cruiser on the Shannon 2. RENEWABLE ENERGY FOR CLEAN SUSTAINABLE TRANSPORT A cheaper alternative which can be considered in the shorter-term is waste cooking oil. Its properties are Most European cities are experiencing ever growing more variable than those of pure unused oils so traffic conditions leading to increasing problems of quality control of the incoming oil, as well as the congestion and emission levels with a consequent ester produced from it, will be important. loss of quality of life. This is particularly true of Nevertheless, this is an option that could be of tourist destinations most of which suffer from particular interest in tourist areas. A good collection seasonal peaks in their traffic levels. system is necessary and can contribute to solving a
waste disposal problem as its use in animal feed is
likely to be more restricted in the future.
Biogas is produced from organic waste as a by-
2.2 Renewable energy for electric vehicles product of sewage treatment and has similar
Wind energy is a widely available source of properties to compressed natural gas (CNG) as a
renewable energy particularly in NW Ireland which vehicle fuel. The use of biogas is particularly
has one of the most favourable wind regimes in attractive from the point of view of greenhouse gas
Europe where there has been a number of wind farm abatement as no net CO2 is produced and would
developments in recent years . have potential applications in many tourist locations.
London Underground, interestingly, has identified offshore wind power as a long term strategic energy source and the use of local wind energy is seen as a possible development in Sligo harbour in a second phase of the project.
Solar energy for transport is a novel concept in
Europe. One example is the photovoltaic (PV) recharging station for electric vehicles in Palermo where 95 electric vehicles were purchased under ZEUS. The PV modules form the roof of a cantilever structure which shades the electric vehicles while they are charging and keeps them cool. The plant produces enough electricity each year to drive the vehicles about 90,000 km. This is an unlikely option
though for Sligo given its Northerly latitude.
Figure 2: Biogas refuelling in Stockholm Stockholm has four refuelling sites for biogas with the fuel being produced at a sewage treatment facility and distributed to the refuelling stations by truck. Under the THERMIE project ZEUS,
Stockholm introduced over 200 biogas vehicles and
increased the production of biogas significantly . At a national level in Ireland there is significant potential to produce biogas from the biomethanation of domestic, industrial and agricultural wastes and considerable quantities are vented from landfill sites. For the purposes of this project however it was concluded that a suitable form of biogas would not
be available locally in the short to medium term. Ethanol is another petrol alternative which is being Figure 3: Photovoltaic recharging in Palermo used, notably in Sweden, in various forms such as E85 (a blend of 85% ethanol and 15% petrol), E10 and E5 . It is currently available at 8 refuelling Hydro-electricity is the most likely and convenient
sites in the Stockholm region. source of renewable electricity for Sligo. It is the
most readily available, with the potential to utilise There is a long tradition in Ireland of growing barley the river Garavogue which runs through the centre for the brewing and distilling industries and sugar of the city from Lough Gill to the sea. This option beet for the sugar industry. In recent years there has will now be examined in more detail. been significant production of potable alcohol from whey residues but is not expected to be available for
biofuel purposes in the near future.
river at low water flows. This would mean that 3. DEVELOPMENT OF HYDRO-
returning migratory fish would be able to pass ELECTRICITY RESOURCE IN SLIGO
rapidly upriver and not be stressed by having to wait
in Sligo Bay. 3.1 The hydro-electricity resource
The Garavogue river runs through the centre of the
3.3 Future potential city from Lough Gill which is 3km upstream and
Potential available power is directly related to the 6.5m above sea level. In the past there were two
flow of water and the head. The average head at the mills situated in the stretch of river which runs
upper weir has been increased from under 1m to through the city centre. The river is tidal below the
1.5m and the long term mean flow on the river has second or lower weir as it opens out to the Atlantic.
been measured at 10.54 m3/sec (excluding fish pass). In a national survey carried out in 1898 the total
This gives a potential available power at this weir of effective hydro potential of the river in Sligo city
about 120 kW. was estimated to be 200kW continuously. Over the
past 100 years all the hydro installations were let go
The upper weir is still classed as a low head site and into disuse .
either a Kaplan turbine or an Axial Flow turbine from Newmills Hydro have been identified as being best suited and requiring little modification to the existing civil works. Their advanced guide vane and runner blade control systems ensure the highest possible efficiency output from the turbines over a wide range of flows .
This completes the first part of the energy chain i.e. river (hydro) energy to turbine to generator to electric energy. To extend this energy chain to electric vehicle it is necessary to insert energy storage and vehicle charging elements into the chain at this point. 3.4 Energy storage and electric vehicle charging
The main option envisaged is for the hydro- electricity to feed directly to a storage system consisting of a battery bank which would be used for
the charging of electric vehicles. Modern battery
systems are highly sophisticated with microprocessor Figure 4: Lake Isle of Innisfree
controls and are maintenance free. The modular
units are safe and compact and integrated HVAC
equipment maintains an optimum environment for 3.2 Recent developments
To meet the increased demands for water in a maximum performance and long life. Such a system growing city, a new water storage scheme is would also enable fast charging of electric vehicles currently under construction. This has involved the with minimal impact on the local grid. upper weir being replaced and raised in height (adjustable) and a new fish pass being installed. At Mains-based fast charging systems are also being the same time a new hotel development is taking developed, both conductive and inductive. All these place at the site of the old mill adjacent to the weir. options will be studied in more detail including Sligo Corporation insisted in the planning sizing, distribution and backup. More detailed permission for this development that the old mill economic analysis has also still to be undertaken race be preserved, thus retaining the possibility of including the study of storage and charging systems reinstalling a hydro scheme. in Luxembourg and Stockholm.
Commercial developments at the lower weir have 4. ELECTRIC VEHICLE OPTIONS left the mill race unusable without intervention works. However the Fishery Authorities are keen 4.1 Electric vehicle procurement that this weir and fish pass are restored as it would In recent years a wide variety of electric vehicles result in a reasonable depth of retained water in the have been coming on the market ranging from
bicycles to buses. But various obstacles have minibuses and electric minibuses were examined. hindered their widespread use such as their high cost, The findings of the THERMIE project lack of infrastructure and a lack of sufficient SAGITTAIRE and a previous study by the authors incentives to boost early market penetration.  lead to the conclusion that a suitable hybrid-
electric minibus is not yet commercially available. A To remove these obstacles the ZEUS project got more likely option in the short term might be the involved in purchasing and putting into use over electric minibus Tecnobus demonstrated in Florence
1000 zero and low emission vehicles. The vehicles under the THERMIE project JUPITER. A number of were purchased through a common procurement these buses have also come into service in Liverpool process which has already resulted in the price of under JUPITER-2 and their performance will be some electric vehicles, such as the Citroën Berlingo closely monitored . van and Fiat Elettra car, coming down to the same level as their conventional equivalents. There is a Particular interest has been shown in the ultra light growing interest from third parties in the ZEUS tram developed by the UK project partner Parry common procurement process and this will be People Movers Ltd. The principal features of this followed with interest by the project. system are its low infrastructure cost and unique
flywheel energy storage. This low voltage system 4.2 Electrically assisted bicycles combined with regenerative braking results in a very A small fleet of electrically assisted bicycles is being low energy requirement. made available for hire with support from the INTERREG programme (through Energy Challenge - a joint Republic of Ireland/Northern Ireland initiative). With the input of ADFC, the German partner in the project, a bike station and a bike infrastructure is currently being designed. Sligo is linking up with Northern Ireland Electricity (NIE) to promote the acceptance of these bicycles and
demonstrate their potential to replace the private car
for travel to school, shopping and work.
Figure 6: Parry light tram If used as the only source of power, the flywheels need to be recharged at electrical supply points up to 2km apart which would be ideally suited to the system of energy storage envisaged. All-in-all it is an extremely environmentally friendly system being quiet running, emission free and requiring no
overhead or underground cables on the street. This
enables the tram system to be installed with minimal disruption and to run either on segregated rail or in traffic . 5. SUSTAINABLE MOBILITY FOR SLIGO Figure 5: Electric bicycle Sligo urgently needs a transport plan which will integrate infrastructure development with clean public transport and satisfy the mobility needs of its 4.3 Public transport and ultra light tram options citizens in a sustainable manner. As the main emphasis of the project is on local public transport, options such as hybrid-electric
The project is studying the concept of an urban (Swedish Transport and Communications transit corridor based on the ultra light tram system Research Board, www.kfb.se), 1998
 Turbowinds technical sheets. outlined above. This would integrate with a small
www.turbowinds.com urban bus system using the Rendezvous-concept  Maguire & Bracken. Hydro Electric Potential at whereby arrival and departure times of buses are Sligo Weir, 1981 highly co-ordinated . The public bus operator,  Newmills Hydro. Water Turbines. Bus Éireann, has just initiated Sligo’s first urban bus www.newmillshydro.freeserve.co.uk service which is a positive step and the railway  P. Bell, J. O’Malley & L. Dauby. Hybrid station has been identified as an ideal interchange Vehicle rd UITP International point making it the transport node for local, regional Development in Europe, 53Congress, Toronto, May 1999 and national public transport.  JUPITER-2 newsletters. www.jupiter-2.net Conversely, a controversial plan for a National  The Challenge of Ultra Light Rail. strategic road corridor would involve the destruction Tramways and Urban Transit, No. 733, Jan 1999 of over 50 houses and some historic warehouse  Assoc. of Town Centre Management, London. buildings at the old dock, cut the train and bus Integrated Transport for Town Centres, 1999
stations off from the city centre and would not  Planning Dept., University College Dublin.
Sligo 2020 Vision, 1998 integrate with public transport or other mobility measures. Sligo is the only city in Ireland with no
out-of-town shopping centre and all city centre
shopping areas are within walking distance. A
previous report identified city centre streets suitable
for giving priority to public transport and
pedestrians over the private car . The transit
corridor outlined above would incorporate all
relevant types of mobility interchange such as: Park
& Ride, bicycle to bus, train to tram, train to bicycle,
tram to bicycle, etc.
While the ALTENER study is not complete, the
indications are that there would be sufficient hydro-
electricity to supply the intended mix of passenger
electric transport vehicles in the urban environment
of Sligo. This would feed into the centre of the
transit corridor, with wind energy feeding into both
ends of an extended corridor in the longer term, thus
providing a unique, innovative and autonomous
system in the Irish urban landscape.
 P. Bell, J. O’Malley & W. Bodewigs.
Renewable Energy for Local Public Transport,
REBUILD, Barcelona, Oct 1999
 Connaught Regional Energy Study. DG XVII
Regional and Urban Energy Planning, 1995
 B. Rice. Promotion of the Use of Vegetable Oil
as a Diesel Engine Fuel Extender/Replacement
in Ireland. ALTENER, April 1995
 ZEUS newsletters.
 T. Månsson. Clean Vehicles With Biofuel, KFB