[Pick the date]
Group 2
Bicycle Life-cycle Study
Alexeis Huaiquin Rosas, Rosas, Daruska Miric Fuentes, Ryo Nakakido, Nakakido, Aurélien Delrieu & Pouya Saboktakin
Summary/Abstract In this project the life cycle of a bicycle is studied. This study goes through the most important steps in which an average bike is produced. Also the principal (raw) materials are composed and used in this process as different inputs are considered as well as the output flows in form of end product, manufacturing wastes and environmental emissions. In the first step, the different sub processes needed for the manufacturing of the most relevant materials of the bikes are shown, also showing the different output of wastes generated. The construction process of a common bike is going to be explained more accurately in the second part of the project. The same study regarding environmental impacts analysis is performed on the raw material extraction process, the use phase and the after-use phase of a bike. To finish the explanation of the life cycle, the material usage and waste generation of the maintenance of the bikes is considered, and in the last part of the project the final destination of each part of the used bikes (which can be disposed in landfilled or recycled) is shown. There is a discussion about a better environmental behavior in the life cycle of the bicycles that can be produced by more recycling of the different parts and materials of the bikes or the improvement of the efficiency of the energy systems implicated in the whole process.
1|P a g e
CONTENTS Introduction ........................................................................................................................................ 3 Objective ............................................................................................................................................. 4 Method ............................................................................................................................................... 4 1)
Resource extraction phase ......................................................................................................... 4 Components and materials of an average bicycle ........................................................................................ 4 Process and emissions associated to the extraction of the materials ......................................................... 5
2)
Process phase ............................................................................................................................. 8 Tires ................................................................................................................................................................ 9 Chain............................................................................................................................................................. 10 Aluminum wheels ........................................................................................................................................ 11 Assembly line (Cannondale bicycles, Pennsylvania) ................................................................................... 12 Transportation ............................................................................................................................................. 15
3)
Use phase .................................................................................................................................. 15
4)
After-use phase......................................................................................................................... 15
Life Cycle Inventory (LCI) .................................................................................................................. 16 Life Cycle Impact Assessment (LCIA) ................................................................................................ 17 Production Processes phase ........................................................................................................................ 17 Total lifecycle environmental impact per passenger-kilometer ................................................................ 17
References ........................................................................................................................................ 21
2|P a g e
INTRODUCTION The life cycle is a framework, mainly used to study and identify the different environmental impacts of a product, which in this case is a bicycle. All the stages of the manufacturing of the process must be considered, including the processes that are needed for the manufacture of the materials that compose a common bike, b ecause those stages also case environmental impacts, just like the main process of the bike manufacturing. The objective of this tool to detect the environmental impacts, from the extraction of the materials to the disposal that allow us to formulate better policies, laws for the waste emissions and ways in which companies may develop strategies for decreasing or controlling the emission of wastes. Also it can be used for the comparison of different product, realizing which one is more environmental friendly. This project is about the life cycle of a bicycle which is made up off steel, aluminum, rubber and other materials that have their own manufacturing processes, which necessitates consideration regarding the construction of the lifecycle of the bikes due to the environmental impacts and the waste generated in the maintenance of this vehicle.
3|P a g e
OBJECTIVE The aim of this work is to research and describe the life cycle of an average bicycle, considering the whole material flow from extraction phase to the manufacturing stage, use and after-use phases in which the first two steps generate the most relevant environmental impacts. Suggestions are made for the categorized impacts like recycling and efficient energy consumption.
METHOD The method used for the research and information gathering was mainly from bicycle’s life cycle papers and books references, also using some internet related information. Also in order to perform a comprehensive and detailed project, the work was divided in four topics- The resource phase, the process phase, the use phase & after-use phase- and allocated to team members to be investigates and developed.
1) RESOURCE EXTRACTION PHASE COMPONENTS AND MATERIALS OF AN AVERAGE BICYCLE Various materials are needed for the construction of a bicycle, and for fulfilling the entire life cycle of this transportation tool, it is needed to research all the chemical compounds that constitute it, and the materials needed for each component for the bicycle. The principal parts of an average or regular bike are the tires, the gears and the frame; meanwhile the subcomponents are the chains, the cranks and the shifters. These components are made mainly of steel, aluminum, mild steel, rubber, foam and PVC. All these materials contribute to give the bikes an average mass of 17 kilograms (simplel.ch 2009). Table 1 shows the components that were mentioned and some other for an average bicycle, including the amount of the average weight of needed for each component:
4|P a g e
Table 1: Materials of each component of an average bicycle .
Component Frame Handlebar Stem Seat Post Bearings Wheels
Material Aluminum Aluminum Aluminum Aluminum Steel Aluminum Steel Wire Rubber/Plastic Aluminum Rubber/Plastic PVC Foam Steel Aluminum Steel Rubber/Plastic Aluminum Steel Aluminum Rubber/Plastic Steel alloyed Aluminum Steel Rubber Wire Rubber Aluminum Steel Other All materials
Average Weight [kg] 2.50 0.23 0.23 0.60 0.60 0.30 0.10 Tires 0.19 0.56 Pedals 0.3 Seat 0.03 0.24 0.03 Chains 0.45 Crank set 0.84 0.36 V-Brakes 0.14 0.28 0.28 Brake handle 0.11 0.11 Cassette Sprockets 0.53 Derailleurs 0.15 0.60 Shifters 0.68 Cables 0.15 Others 1.00 2.00 3.00 0.5 Total 17,09 Source: (M. Leuenberger, R. Frischknecht, Life Cycle Assessment of Two Wheels Vehicles 2010)
PROCESS AND EMISSIONS ASSOCIATED TO THE EXTRACTION OF THE MATERIALS The materials used in the construction of each component are composed from other raw materials that must be refined to get the materials that are used directly in the bikes. One example, the stainless steel that is used in many parts of the bikes, is obtained from the iron ore, material that must be extracted and treated by several processes to become the stainless steel. In other hand, each process that transforms raw materials into useful materials to be used to construct each component of the bicycles generates different wastes and 5|P a g e
emissions. At the same time, these processes need energy and other materials to go on. For example for the reduction process of the iron ore, energy in form of heat is needed which is normally generated by the burning of coal. The incineration of this material generates emissions like carbon dioxide, carbon monoxide, etc. Some of the input of materials and waste generation of the process to manufacture the steel necessary to be used directly in the bikes is shown in the table 2. This consists basically in a mining process for the extraction of the iron ore and refinement. Table 2: Steel manufacturing processes, emissions and raw material.
Steel Process
Material Input
Iron ore extraction
Hematite, magnetite
Carbon dioxide, dust
Heating in absence of air
Bituminous coal
Carbon dioxide
Reduction of the ore
Iron ore, coke, limestone
Removal of sulfur Removal of carbon Alloy melting Annealing
Molten iron, magnesium powder Molten iron, oxygen, quicklime Molten iron, chromium, nickel
Material Output
Waste Output
Calcium silicate
Carbon monoxide, carbon dioxide
Magnesium sulphide
Carbon dioxide
Calcium silicate, calcium phosphate
Carbon monoxide Carbon dioxide
Stainless Steel
Carbon dioxide
Source: R. Bhalla, Life cycle of a bicycle (2011). / http://www.ideasyncrasy.com/
The aluminum that composes the bicycles is obtained through the Bauxite mineral. The Bauxite minerals, just like iron ore is underground, so mining process are required to extract this mineral, and it must be refined and submitted to an electrolysis process. The table below shows the sub process of the aluminum refinement and some of the wastes generated. Table 3: Aluminum manufacturing processes, emissions and raw material.
Process Aluminum ore extraction
Aluminum Raw Material Input Material Output Bauxite
Carbon dioxide, dust
Crushed bauxite, sodium hydroxide solution Sodium Tetra hydro aluminate, Aluminum hydroxide
Silicon, lead, titanium, calcium oxides
Heat
Aluminum hydroxide
Water
Electrolysis
Aluminum oxide, cryolite, carbon
Carbon monoxide, carbon oxide, Aluminum
Bayer’s process
Precipitation
Waste Output
Carbon dioxide
Sodium hydroxide
Source: R. Bhalla, Life cycle of a bicycle (2011). / http://www.ideasyncrasy.com/
6|P a g e
Manufactured by the polymerization of vinyl chloride, chlorate hydrocarbon has to pass many sub processes. It begins with the extraction of oil to obtain the hydrocarbon that composes it. Many materials are needed for the production of this process, like electrolysis and distillation, some of those process (and their materials and waste out puts) are shown in the table 4: Table 4: PVC manufacturing processes, emissions and raw material.
PVC Process Crude oil extraction Refined to naphtha
Raw material Input Shale
Material Output
Petroleum
Electrolysis
Rock salt
Steam cracking
Naphtha (ethane, propane, butane)
Thermal decomposition
Ethylenedichloride, copper
Polymerization
Vinylchloridemonomer
Compounding
PVC additives
Injection molding
PVC compound
Mercury, hexachloronbenzene, hexachloronethane, PCB, octachlorostyrene
Waste Output Carbon dioxide, Sulfur dioxide Volatile organic comp. (Voc)
Carbon dioxide Carbon dioxide Chloroform, hexachlorobenzene, phthalene, zinc, copper, dioxin Dioxin
Source: R. Bhalla, Life cycle of a bicycle (2011). / http://www.ideasyncrasy.com/
Just as PVC, the foam is a polymer composed mainly by hydrocarbon, obtained from petroleum at the first stages of the chain of process to manufacture it. Waste and material output at shown in the table 5: Table 5: Foam manufacturing processes, emissions and raw material.
Process Crude oil extraction Refined to Naphtha Reacting process Polymerization Expansion Layering Cutting
Foam Raw material Input Material Output Shale Petroleum
Waste/Material Output Volatile organic comp.
Di-isocyanate polyol Poly-isocyanate, amine, metallic salt Polyurethane, carbon dioxide Polyurethane, backing-paper Polyurethane foam
Carbon dioxide Polyurethane Foam
Source: R. Bhalla, Life cycle of a bicycle (2011). / http://www.ideasyncrasy.com/
7|P a g e
The rubber is obtained from the natural rubber or resin, which is an organic (hydrocarbon) polymer, adhered in the interior of some kinds of trees that are widely cultivated. Some other sub processes are needed to improve the rubber mechanical characteristics, their material inputs and wastes outputs are mentioned in the following table: Table 6: Rubber manufacturing processes, emissions and raw material.
Rubber Process
Raw material Input
Material Output
Rubber tapping
Rubber sap
Latex
Mixing
Latex acids
Natural rubber
Co-polymerization
Butadiene, styrene
Synthetic rubber
Incomplete Combustion
Crude oil, oxygen
Carbon black
Mixing, re-milling, final mixing
Natural rubber, synthetic rubber, carbon black, sulfur, oil
Waste/Material Output
Carbon dioxide, carbon monoxide
Source: R. Bhalla, Life cycle of a bicycle (2011). / http://www.ideasyncrasy.com/
It’s important to know that almost all the processes to manufacture the materials needed
on the bikes need energy, in form of electricity or heat, and to generate that energy is necessary the use of materials like coal or hydrocarbons for obtaining heat for example, and the burning of these materials generate emissions of carbon oxides, sulfur oxides, VOC, dust, etc. Also there is some processes mainly machinery that seems to not pollute, but all them use electric energy at the end (for example precipitation need electric energy for pumping purposes). This way, it can be said that performing more efficient process, using less amount of energy in each part, less emissions can be achieved. Also the recycling of the components of the materials of the bicycles would be helpful to decrease the amount of raw material that need to be extracted, reducing the energy consumption again and also the waste generation.
2) PROCESS PHASE After considering the environmental emissions of the raw material used in manufacturing a bicycle such as steel, aluminum, PVC, tire and plastic, in this chapter as a next step the aim is to focus on production procedure of bicycle parts such as tires, chain, aluminum wheels, body frame and of course considering the assembly line as a whole image where all these parts meet to end up as an end product.
8|P a g e
The transportation of the final product is considered also in this chapter as the very last step before reaching the customer.
TIRES Tires first were invented in 1888 by John Dunlop; Until the world war 2 bicycle tires were organic but by 1960s synthetic rubber became standard and modern bicycle tire have been made of it ever since. Bike tires are made by the combination of rubber, nylon and bulletproof Kevlar. Rolling machines or banbury mixers are fed by rubber stocks and other chemicals such as silica, Zink oxide, sulfur and also carbon black to increase ti re’s density, elasticity and durability. Nylon could be added in this stage or another separate phase using similar equipment. The milling process shapes the rubber into flat, long strips and ready to be assembled by a highly automated process in which components are assembled on a rotating drum. Exposing heat and hazard of sudden inhale of chemicals while respiration apart from the mechanical risks show the environmental impacts of the wastes energy in form of heat also chemical emission and leach. Besides machinery regular work & maintenance have oil leach and pollution also. Tire builders utilize solvents, such as hexane, which allow the tread and plies of rubber to adhere. Exposure to the solvents is an area of concern for workers and of course should be considered as an environmental impact. In almost the last stage, curing press aims to transform the tacky and pliable material to a non-tacky, less pliable, long-lasting state by utilizing steam to heat (up to 180 degrees for 3 minutes) or cure the tire. This would also reveal waste in form of heat and water consumption. Inspection and testing is performed on random tires focusing on punching and pressure resistance. There are machines simulating the road situation which test tires non-stop for 2 or 3 days in a row and the energy consumption is considerable in this phase. The following table(s) considers the environmental impacts of the “consumption” of electricity and paper regarding their indirect environmental impacts also.
9|P a g e
Table 7: Tire manufacturing processes and environmental impacts
Process/Phase
Tool/Machine
Compounding and
Heavy rolling
Banbury mixing
machine/Banbury mixer
Milling
Heavy rolling machine
Component Assembly and Building
Raw material
Environmental impact
artificial rubbers,
Energy consumption /
Mineral oil, silica, Zink-
Energy waste (heat) /
oxide and sulfur
Chemical leach
Nylon
Energy consumption Energy consumption /
Rotating drum
Glue, solvents (hexane)
Energy waste (heat)/ Chemical leach Energy consumption
Curing and Vulcanizing
Heat press
Energy waste (heat)/ water
CHAIN A bicycle chain is essentially a roller chain that is designed specifically to transfer pedal power to the bicycle’s rear wheel. The manufacturing process starts with a punch press
which cuts and shapes the steel into chain’s inner links. Then the links bake in 1500 Fahrenheit degrees in order to gain more strength. Baked links followed by fast cool down of baked steels strengthens the steel more. Hence lots of energy in form of heat is wasted in this phase. As the next step chemicals such as ceramic and silica powders plus little amount of water are all mixed with links in a donut shape container which polish the links. Then these links take a chemical bath which gives them a nickel Teflon veneer to increase resistance against corrosion and by smoothing the surface allow chain move easily over gears’
brackets. Hence the chemical leach and evaporation is considered as a significant impact despite the low possibility. Assembly machine in the next step forms the chain beautifully by using outer and inner links in a unique order and connects those using spins and rings. Hot oil bath as the next step lubricate the chains and make them ready for the very last step in the process which is cutting by a laser machine. Then different length and model chains are being packed and ready to send. Table 8 expresses more about the raw material and tools in use in each step as well as environmental impacts.
10 | P a g e
Table 8: Chain production processes and environmental impacts
Process/Phase
Tool/Machine
Raw material input
Environmental impact
Cutting links
Punch-press machines
Steel sheet
Energy consumption
Cooking links
Furnace
Fuel/Coal
Polishing links
Doughnut-shaped mixer
ceramic & silica powder
Chemical Leach
Anti-corrosion veneering
Chemical pool
Nickel
Chemical leach
Lubrication
Hot oil bath
Oil
cutting
Laser cutter
packaging
CO2 emission Energy waste (heat)
Oil leach Energy waste (heat) Energy consumption Energy waste (heat)
Papers, plastic bags, cartons
Paper consumption Plastic penetration into the environment
ALUMINUM WHEELS In a very simple process aluminum tubes are bent with bending machines to form a circular shape. Right after measuring the rim, a cutting tool separates the rings and for almost a rim. Two ends of a rim is joined by an automatic welding machine which cause a welding line sign on the rim hence a sharp vibrating cutting tool smooth the weld line. So far the automation involved in the processes is considered as energy use sources as well as the probable maintenance chemical and oil uses (and leach) are environmental impacting issues. More hazardous impacts happens before the end welding of rims when the acid bath removes the dust and other contaminants from the rims surface and later on the multiphase heating process in order to increase strength of the metal (that re-structure the molecules of aluminum) which consumes electricity or fossil fuels or coal also emit Co2, So2 and other particles and gases in to the air. After all these processes comes up the anti-corrosion coating in chemical pools using an electrical charge to draw the coating particles onto the rims’ surface. The process is called
Anodization. A computer guided machine shaves off the amount of anodized metal for nearly one third of the rim’s surface. This creates a smooth perfectly flat area for the brake pads to grib.
11 | P a g e
Another computer guided machine drills holes for tiny aluminum nipples which hold the aluminum spokes to the rim. Then a manual phase of assembling wheels is performed then lacing the wheel in which spokes are fixed and connected in rim’s holes. Truing the wheel is the important step in
aligning the wheel by adjusting the spokes using a specific wrench until the wheel is finally trued. After the manual phase, robots make any necessary tensioning adjustments afterwards. Depending on the model a wheel can have between 10 to 46 spokes. Overall, table below tells more about the details regarding the steps priority and environmental impacts. Table 9: Environmental impacts of manufacturing aluminum wheels
Process/Phase
Tool/Machine
Raw material
Environmental impact
Bending
Bending machines
Aluminum tubes
Energy consumption
cutting
Cutting machine
Acid wash
Acid bath
Energy consumption Acid(s)
Chemical Leach Energy consumption
Heating
Heating room
(after burn gases emission)
End welding
Welding machine
Weld line Milling
Milling machine
Anti-corrosion coating
Chemical pool
Grid line Milling
Milling machine
Spokes installation
(Manual)
Testing
packaging
Energy consumption Energy waste (heat) Energy consumption Chemicals
Chemical leach Energy consumption
Alignment testing
Energy consumption
machines Papers, plastic bags, cartons
Paper consumption Plastic penetration into the environment
ASSEMBLY LINE (CANNONDALE BICYCLES , PENNSYLVANIA ) Having Profile and pipe as inventories, first of all requires transportation inside the site to be places in warehouse and then to the cutting phase. This would need electricity or fuel
12 | P a g e
to provide these transitions besides the emitted gases in case of using lift-trucks with diesel engines for instances. CNC machines in the cutting step make parts out of aluminum or steel pipes which would make even more sense when a plasma or laser cutter create accurate holes and channels on tubes. Energy consumption and energy waste in form of heat is considerable at this stage. In order to give the group the number of tubes as a frame, tack welding now gives the general shape of the frame which also allows the parts to be handled as one unit from now on. At the welding department attachments are completed and would be completed by a sanding process which removes all imperfections in welded parts. This ensures there is a nice smooth transition between tubes where the weld I concerned. At this procedure also heat treatment is performed to increase the strength of the frame. Then in a manual phase the alignment of the f rame is tested. Some extra machine works for dressing appropriate surfaces, wholes, etc. is done before the frames are sent for painting. A neat frame with no oil or any material on its surface, would end up with a better painting quality, hence a chemical bath is done to prepare the frames respectively. After the painting phase which in this case in done manually, frames are sent to heating room to be then transferred to the decal room where all decals are applied manually. Decaled frames are then back to the painting room to get this ti me a protection layer over decals. Now the frame is ready and from now on all other extra parts mentioned in the previous parts meet here to form the end product. In pre-assembly location swing arms or any other hardware such as shock absorbers are attached to the main frame. Then in parallel components for handle bar which are made up of shifters, grips are put together to be fixed on the main frame later on in the assembly line. On assembly line the hanging bike moves along and each part such as, handle bars, wheels, gears, shifters, chain, any other small component is put on and fixed respectively. After the quality control, bikes are ready for packing in which paperboards, cartons and plastic bags are used. The overall flow can be grasped from the chart below.
13 | P a g e
Chart 1: Assembly line scheme
Source: Ruey-Shun Chena, Mengru (Arthur) Tu (2009), Development of an agent-based system for manufacturing control and coordination with ontology and RFID technology Table 10: Environmental impacts of assembly line of bicycles
Process/Phase
Tool/Machine
Raw material
Environmental impact
In-house transportation
Lift trucks
Fuel
CO2, SO2, etc emission
Cutting
Cutting machine
Accurate channeling
Plasma or laser cutters
Tack welding
Welding guns
Welding
Welding machines
Sanding
Sanding machines
Energy consumption Energy consumption/ Energy waste (heat) Energy consumption Electrodes
Energy consumption Energy waste (heat)/ water Energy consumption Energy consumption/
Heat treatment
Heating room
Electricity / fuel
Energy waste (heat) CO2, SO2, etc emission Energy consumption/
Dressing machinery
Drilling machines
Cooling oils/liquids
Frame wash
Chemical pool
Chemicals
Chemical leach
Painting
Paints
Chemical spray leach
Decaling
Glued decals
Decal fixing
Fixator sprays
Assembly
Packaging
14 | P a g e
Assembly line electric tools
Cooling liquid leach
Chemical penetration into the environment Chemical spray leach Energy consumption
paperboards,
Paper consumption/
cartons and plastic
Plastic penetration into the
bags
environment
TRANSPORTATION The process phase of the bicycle’s life cycle does not end here and actually there is one more step before starting the “use phase” and that is transportation of the end products
to the consumption area. Transportation can be done directly to the sport or toy stores and/or to the local distribution centers. The main environmental impact is of course matter of exhaust gases emitted into the atmosphere by truck and container. Considering the maintenance of these vehicles would add more items to these impacts as well.
3) USE PHASE Bicycle is known as a green transportation mean hence it is a difficult task to mention the direct environmental impacts generated during the use phase. The motive power source in the bicycle is produced by human muscle power where the required impulsion energy is obtained from food consumption. Emissions produced by bicycle use in this phase (CO2eq, SO2, PM, CO, HC, NOx and Pb) are largely zero and do not consider emissions required by the production of food. But the indirect impacts through using of spare parts like tires, brake grips, wheels, etc. should be considered and the reason is the increase of the order in the manufacturing phase where the impacts have been already mentioned. The maintenance process uses oils, lubricants e.g. grease and other chemical items which cause soil pollution for instance because of leaching. 4)
AFTER -USE PHASE Now a day’s wastes utilization is a major issue to get clean and healthy
environment. The production of waste tires throughout the world is estimated to be 1billion tons tires-all types- per year (Williams, 2005). As the environmental pollution caused by waste tires has become a rigorous issue in global environment protection, Pradhan and Singh (2011) discussed that termal pyrolysis of tire-in general- by batch reactors at 600°C would lead to the pyrolytic oil that has significantly higher calorific value and thus can be used as an alternative to fossil fuel after proper treatment. Wang et al (2011) also discussed the use of recycled tire crumb rubber as an alternative electrode material in microbial fuel cells as the tire particles showed satisfying
15 | P a g e
conductivity after 2-4 layers of graphite coating. This is a good example of bike tires afteruse phase. Bicycle parts that are made of steel can be recycled as scrap metal, specifically as ferrous metal, in the municipal drop-off center or scrap metal center. Recycling it is important, because for every ton of steel recycled, 2500 pounds of iron ore, 1400 pounds of coal and 120 pounds of limestone are conserved. The importance of recycling aluminum is that the energy saved by recycling 1 ton of aluminum equals the amount of electricity used by a typical home within a 10 years period. nd
Also, if the bike can still be used, there is possibility of resale in 2
hand markets,
etc. also the spare parts might be used after reassembling.
LIFE CYCLE INVENTORY (LCI) Seen from a general form, Table 11 shows the material inventory used in the bicycle production process, also shows the material inventory for electric bike, electric scooter, motorcycle and bus. The production process, for all the vehicles, consists of the following stages: mining or extraction of raw materials, processing those raw materials into usable refined material, fabricating refined materials into individual parts, and assembling the parts into the final vehicle. The material inventory was determined from leading vehicles producing 1
companies in China.
Table 11: Inventory of materials in vehicles production process
Source: Cherry, C.R. (2009). Comparative environmental impacts of electric bikes in China. Transportation Research Part D 14, 281-290. 1
Cherry, C.R. (2009). Comparative environmental impacts of electric bikes in China. Transportation Research Part D 14, 281-290. Page 2. 16 | P a g e
During the manufacturing process of bicycles are generated various types of emissions. It is important to specify that the types included de emissions due to the mining and production of ferrous and non-ferrous metals, and the production of plastic and rubber. The inventory between production process and environment are: Air pollution (SO2), Air pollution (PM), Greenhouse gas (CO2eq), Waste water and Solid waste.
LIFE CYCLE IMPACT ASSESSMENT (LCIA) PRODUCTION PROCESSES PHASE Some of the wastes, generated in the stages mentioned before, come into contact with the environment causing an impact on this. In the Table 12, the impact in the environment and the energy use for bicycle, electric bike, electric scooter, motorcycle and bus is illustrated. These emissions were calculated using the material inventories from producing companies in China. The environmental impact considers data reported in industrial statistical yearbooks, to identify emission intensities (kg pollutant per kg of material produced). Also, does not include transportation logistic impact. Table 11: Environmental impact in vehicles production process
Source: Cherry, C.R. (2009). Comparative environmental impacts of electric bikes in China. Transportation Research Part D 14, 281-290.
As seen in the table, the waste water is a major cause emissions impact in the bicycle process. In this, control can be focused or can design strategies for decreasing environmental damage.
TOTAL LIFECYCLE ENVIRONMENTAL IMPACT PER PASSENGER -KILOMETER In this point it is show the average emissions produced, in the production and use phases, per passenger kilometer traveled for bicycle, electric bike, electric scooter,
17 | P a g e
motorcycle and bus, this is an important comparison of the environmental impacts. Table 13 gives the emissions of both faces together. 2
Several assumptions were made to develop Table 13, which are : -
Lifespan of 197000 km, 1000000 km, 20000 km, 60000 km and 50000 km for car, bus, bicycle, motorcycle and electric bike respectively.
-
Average load factor of 1-3 pax for car, 25-75 pax for bus, 1 pax for bicycle, 1-2 pax for motorcycle and 1-2 pax for electric bike. This factor assumes generally uncongested city.
-
100% recycle rate and one battery every 10000 km for electric bikes and one battery every 3 years or 250000 km for buses, one battery every 3 years or 75000 km for car, one battery every 3 years or 18000 km for motorcycle. Table 12: Environmental Impact per passenger-kilometer
Source: Cherry, C.R. (2009). Comparative environmental impacts of electric bikes in China. Transportation Research Part D 14, 281-290.
Table 13 shows that the most important bicycle emission is carbon dioxide, hence it can help designing a strategy to eliminate or reduce this environmental impact. The vehicle that make more emissions of carbon dioxide is the car, and as expected the bicycle the more friendly with the environment. So it can be said that the bikes are the most efficient option of transportation, in ener gy consumption per distance terms.
2
Cherry, C.R. (2009). Comparative environmental impacts of electric bikes in China. Transportation Research Part D 14, 281-290. Page 7. 18 | P a g e
Discussion As all the processes associated with the manufacturing of a bicycle which cause different environmental impacts were researched; these impacts can be detected by the realization of a life cycle (in this case for the bikes), tool that allow us to organize and classify the different stages of the process of the bicycle manufacturing, from the extraction of the raw materials that compose the bikes, through the manufacture this vehicle, and until the final destination, that could be the disposal in landfill, recycling or resale. There are inputs in the bicycle life cycle in form of energy and raw material as well as outputs if form of disposed parts or wasted energy hence production optimization and reuse or recycling mean to keep the material in the cycle and prevent them leaving it. These stages are shown schematically in the following figure: Fig 1: Diagram of the life cycle of the bicycles.
Source: http://www.apartmenttherapy.com/conduct-a-mini-life-cycle-asse-124497
19 | P a g e
The most important environmental impact detected in the whole chain of process was the emission of carbon dioxide, the most relevant greenhouse gas of these days. The major part of carbon dioxide (as carbon monoxide, sulfur dioxide, and others) emissions have their source in the manufacture of the bike itself, and in the manufacture of each of the different materials that compose the bicycles, considering the extraction and refining of the raw materials, works that have their own sub processes that could be heating, cooling, transport, precipitation, distillation, and many others, and each one of those processes need energy in form of heat or electricity to be performed. These emissions of waste could be direct or indirect. A direct way to cause an environmental impact through the emissions of carbon dioxide could be for example during the transportation of raw materials, job that must be done by vehicles that use f uel and generate carbon dioxide. The same goes for industrial processes like heating that could be done by heat exchangers or furnaces, burning hydrocarbons like fuel oil, coal, or many others sources, generating carbon dioxide, carbon monoxide, sulfur dioxide, etc. Also there are other kinds of direct waste emissions that must be mentioned, these are the industrial solid wastes, which final destination are principally in landfills, and the industrial liquid wastes, that are almost always treated in the plant of process to be discharged in rivers or in the sea. The indirect way of polluting consists in all the process that not generates emissions directly, but uses other sources of energy like the electricity to perform their jobs. An example of this is the pumping of fluids (which don’t generate emissions), most of the pumps need electricity for working, and this electricity could be generated at the end by thermo electric power plants, which burns hydrocarbons and pollute greenhouse gases. This lead us to the conclusion that investing in more efficient process in the whole chain of the bicycle manufacture process, will help to decrease the energy consumption (decreasing the amount of hydrocarbons burned) and decreasing the amount of greenhouse gases generated. An example of investment could be the installation of insulation in pipelines, decreasing the leakage of heat. Another considerable step about the life cycle realized is the final stages and the important of recycling the parts. This would help decreasing the amount of raw material input in the cycle. Consequently the amount of greenhouse gases and waste generated in the first stages raw material extraction and production would also decrease.
20 | P a g e
References
Cherry, C.R. (2009). Comparative environmental impacts of electric bikes in China. Transportation Research Part D 14, 281-290.
Debalaxmi Pradhan and R. K. Singh (2011), Thermal Pyrolysis of Bicycle Waste Tyre Using Batch Reactor, International Journal of Chemical Engineering and Applications, Vol. 2 , No. 5 , October 2011
Ruey-Shun Chena, Mengru (Arthur) Tu (2009), Development of an agent-based system for manufacturing control and coordination with ontology and RFID technology.
Heming Wang, Matthew Davidson, Yi Zuo, Zhiyong Ren.Recycled tire crumb rubber anodes for sustainable power production in microbial fuel cells.
Williams PT, 2005. Waste Treatment and Disposal, 2nd ed; Wiley and Sons London.
http://www.youtube.com/watch?v=JM_x0qPM8Ok
http://www.youtube.com/watch?v=h8j5-dC6_x8&feature=endscreen&NR=1
http://www.youtube.com/watch?feature=endscreen&v=xYUOLGEPw9Q&NR=1
http://www.youtube.com/watch?v=xYUOLGEPw9Q&feature=related
http://www.youtube.com/watch?v=XMdrPxD3I_Y
http://www.co.anoka.mn.us/v2_dept/iwm/show-item-info.aspx?id=99
http://aarline.info/hotaar/?p=1
21 | P a g e
