LIFE 03 ENV /S/000592 August 2006 CLEANOWA electric-hybrid technology for more environment-friendly waste collection
With funding from the EU s Environment Fund Life and in close cooperation with the Committee for Sustainable Water and Waste Management, City of Gothenburg (Kretsloppsnämnden), Swedish waste and recycling company Renova has conducted a project entitled CLEANOWA (Cost-effective system for clean and NOiseless WAste collection). The purpose of this project was to run a fullscale trial of and evaluate a new system for waste collection with reduced environmental impact. Table of contents Introduction 2 Background 3 Activities 3 Vehicles 3 Route planning 4 Training 5 Emissions 5 Catalytic converters 5 Fuel and electricity consumption 5 Noise 5 Survey 6 Work environment 6 Production 7 Economy 7 Marketing and PR 7 Results and conclusions 7 Introduction Based in Gothenburg, Renova AB is western Sweden s leading waste and recycling company. The company is owned by 11 municipal authorities, and offers municipal councils and businesses services covering the entire recycling chain consultation, training, transport, sorting and treatment of waste including composting, incineration for energy recycling and landfill. Renova handles 700,000 tonnes of waste each year. Its vehicle fleet consists of around 150 heavy vehicles for transporting waste of various kinds. For many years, Renova has been working actively to find new solutions for reducing the environmental impact of the transportation of waste. As early as in 1994 and in cooperation with Volvo Trucks, Renova modified a rear-loading waste collection vehicle to run on CNG (compressed natural gas). Today, Renova has 50 CNG powered trucks for waste collection. This investment in CNG vehicles is unique in Sweden and in the world at large. In another similar effort to reduce environmental impact at Renova, water (containing propylene glycol as anti-freeze) is used instead of oil in the waste compaction unit s hydraulics system in a number of vehicles. Renova s most recent effort to reduce the environmental impact of its vehicle fleet is the development 2
of an electric-hybrid waste collection vehicle in cooperation with Volvo Lastvagnar AB (Volvo Trucks), Norba AB and ETP Kraftelektronik AB. The new vehicle is equipped with a combination of a CNG engine with a highly efficient catalytic converter and electric-powered waste compactor, greatly reducing environmental impact through lower fuel consumption, reduced emissions and quieter operation. Experiences arising from the development of this vehicle formed the foundation for the CLEANOWA project. Background Studies in Sweden have shown that waste collection vehicles used in densely populated areas stand idle at collection points for around 60 percent of the time they are in production. The engine is only used for barely half of this time for loading and compacting the waste (see Figure 1). The rest of the time, when the collectors are fetching and returning containers at the collection point, the engine is idling without any useful purpose. This is inefficient usage of the engine, and causes unnecessary noise and emissions. Even when the engine is used for loading and compacting at the collection point, there is unnecessary environmental impact since the engine is optimized for running the vehicle and thus has a power that vastly exceeds that which is needed for the loading and compacting phases. Time for transport 40% Idling 35% Time at collection point 60% Compacting 15% Figure 1. The phases in the work cycle for waste collection vehicles in the urban environment. Loading 12% The new system for reducing the environmental impact of waste collection, which the CLEANOWA project has tested and evaluated, comprises several different parts. The use of a new waste collection vehicle with electric-hybrid technology, which is better suited to the collection of waste in densely populated areas than conventional rear-loading waste collection vehicles. Computerized route optimization Training of waste collectors in managing the new vehicle and how to drive fuel-efficiently (EcoDriving). The goal was for the system to lead to reduced noise and air pollution during waste collection in the urban environment. This in turn will lead to a better local environment and thus increased quality of life for residents and a better work environment for waste collectors. Activities The project has comprised the following activities: 1. Preparations for the installation of the system. This included gaining acceptance for the project among the personnel, route planning and the acquisition of the ten vehicles to be trialled in the project. In addition, it included arranging parking bays with mains sockets for recharging suited to the new vehicles. 2. Training of waste collectors in managing and operating the new vehicles and in Heavy EcoDriving (driving heavy vehicles more fuel-efficiently). The workshop mechanics were also given special training in how to serve and maintain the new vehicles. 3. Commissioning of the vehicles into daily production. 4. Full-scale tests comprising monitoring of the vehicle s function and availability over an extended period of time. 5. Evaluation of environmental impact. Measurements of emissions and noise levels. The system s functionality was also tested, as well as the vehicles energy and fuel consumption, and the system s cost-effectiveness. In addition, a survey of residents and decision-makers was conducted. 6. Marketing and PR activities nationally and within the EU, with the purpose of disseminating knowledge about and experience of the system. Vehicles The principle for the new vehicles was to use electric-hybrid technology during stationary phases of the work, that is, loading and compacting. This means that the internal combustion engine does not need to be idling unnecessarily during long collection stops. When the vehicle stops at a collection point, the internal combustion engine switches off automatically after 30 seconds. During loading and compacting of waste, the electric motor is used instead to power the hydraulics. The electric motor is quiet and does not generate any emissions. 3
6. A 72 V electric motor sits behind the driver s cabin and powers the hydraulics for lifting, loading and compacting waste. 1. Start button and auto-stop function in the driver s cabin. 1 6 2. Battery charger for mains connection under the driver s seat. Figure 2: Electric-hybrid waste collection vehicle. 2 3 5 3. Three 24 V generators charge batteries during operation. 4 5. Catalytic converter for CNG engine. 4. Two 72 V batteries. Technical specifications Engine rating Load capacity Fuel Gas tanks Gas pressure Electric motor Max discharge rate Batteries Battery weight 150 kw (205 hk) 6 tonnes CNG or biogas 4x120 liter tanks 200 bars 72 V 560 Ah for 10 hours 2x72 V lead-acid batteries Approx. 1100 kg The vehicle has a start button so that the collectors can easily start the vehicle again after stops where the engine has been automatically switched off. This facilitates operation, as the collectors do not need to use the key to start the engine again after such stops. The vehicles are CNG-powered, and can run on both natural CNG and biogas. The engines sense and adapt their operation to the quality of the CNG in the tank. The electric-hybrid vehicles are also equipped with catalytic converters specially designed for CNGpowered vehicles. This type of catalytic converter differs from conventional types in that a heat exchanger inside the converter raises its operating temperature. A higher temperature makes it easier to reduce emissions of hydrocarbons such as methane for example. The electric motor is load-sensing, that is, only the amount of electricity needed for the load is used. The batteries that drive the electric motor are recharged during the night from mains outlets installed in the garage. One charge is sufficient for a full day s usage. If the battery charge should sink to an unfavourable level, the batteries are charged during operation by three generators. Route planning The CLEANOWA system also includes the use of a computerized route planning software, Route Smart. This tool is used to optimize the routes taken by the vehicles, which leads to reduced time on the road and thus reduced emissions. An outline of how Route Smart works is shown in Figure 3. With the help of map data (1) the program calculates the optimum collection routes (2). The optimization is in two steps: The area is divided into several parts, each part corresponding to one vehicle s route (allocated daily). The route for each individual vehicle is optimized. The result of the optimization is transferred to a system in which the planners and collectors can see the driving itinerary (3) for each vehicle. Customer info Road info Map Route Smart Route planning Figure 3: Outline of route planning using Route Smart. 4
Training Collectors have been trained in how to drive and operate the new vehicles and repair workshop personnel have been trained in how to service and repair the vehicles. Another part of the system is that the collectors are trained in Heavy EcoDriving, a training programme that includes theory and practice and aims to reduce the environmental impact of waste transportation through driving more fuel-efficiently. Emissions During the project, the emissions from the electric-hybrid waste collection vehicles and conventional CNG and diesel vehicles were measured. Figure 4 shows the reduction achieved when using the CNG-powered electric-hybrid vehicle compared with a conventional diesel vehicle; and the reduction attributable to the electric-hybrid technology itself when applied to a CNG-powered vehicle. Catalytic converters Our measurements show that the new catalytic converters are significantly more effective than conventional catalytic converters in converting greenhouse gases into carbon dioxide and water. Conventional catalytic converters show an efficiency of between 23 and 26 percent that is, the percentage of the methane that goes into the catalytic converter that is converted into carbon dioxide and water while the rest is emitted to the air. The new catalytic converters however showed an efficiency of 80 percent. 100 80 60 40 20 0-20 NOx HC CO Particles CO 2 Reduction compared wirh diesel vehicle (%) Reduction from electric-hybrid technology (%) Figure 4. Results of emissions measurements. Compared with conventional diesel vehicles (not equipped with a particle filter), the electric-hybrid vehicle emits between 70-94% less nitrogen oxides, hydrocarbons, carbon monoxide and particles. For carbon dioxide, the reduction is only a few percent. For the electric-hybrid technology alone 1 applied to CNG vehicles, an improvement of around 40% was found for carbon monoxide, particles and carbon dioxide. For nitrogen oxides and hydrocarbons however, results showed an increase in emissions of one and four percent, respectively. This can be explained by the high levels of nitrogen oxide and hydrocarbon emissions resulting from starting the engine again after work was completed at each collection point. 1 The performance of the new catalytic converters and the effects of route planning and EcoDriving are not included in this result. Figure 5: Cross-sectional view of the catalytic converter. The exhaust gases enter the catalytic converter and then are turned back as shown above, preheating the incoming gases. The energy thus recovered generates a hotter environment than inside a conventional catalytic converter, providing more favourable conditions for the oxidation of residual methane. Fuel and electricity consumption Measurements showed that the electric-hybrid technology reduces fuel consumption by between 20 and 40 percent when the vehicles are driven in the inner city areas of Gothenburg. Measurements within the project showed that electricity consumption during loading and compacting of the waste is 2.1 kwh per tonne of collected waste. This gives an annual consumption of around 5 MWh. This should be compared with the 90 MWh per year, approximately, that an electric-hybrid vehicle consumes in the form of CNG. Besides reduced environmental impact, this also means better fuel economy. Noise The noise levels for the four phases in the collection of waste at each collection point are shown in Figure 6. The noise level was measured in front of each vehicle. 5
100 90 80 70 60 50 40 30 20 10 0 Idling Lifting of Loading Compacting containers of waste of waste CNG vehicle Diesel vehicle Electric-hybrid vehicle Figure 6. Noise levels. The biggest improvement (in the form of reduced noise) is found when comparing with a conventional waste collection vehicle that is idling and generating a noise level of around 64-69 db while an electric-hybrid vehicle does not generate any noise at all (after 30 seconds). It is during this phase that the collectors fetch the waste containers. The measurements in the project have shown that this time is approximately 55 percent of the total time that the vehicle is standing at a collection point. During the phase of lifting the container and loading the waste, and compacting it, there is also a significant reduction in noise levels. While conventional CNG vehicles and diesel vehicles generate noise levels of 65-70 db and 75-76 db, respectively, the electric-hybrid vehicles generate noise at only 51-52 db for these two phases of the work. These two phases comprise around 23 percent each of the total time at each collection point. It s important to note that a reduction in noise level of 3 db is equivalent to a reduction of 50 percent in the noise level as experienced by the human ear. When the waste drops down into the waste collection vehicle there is, however, an increase in the noise level for electric-hybrid vehicles compared with a conventional CNG vehicle. However it is important to note that this not a direct result of the electric-hybrid technology per se, but rather a consequence of the height from which the waste drops, and the design of the vehicle s cradle into which the waste falls. The noise that occurs when the waste drops into the cradle is, however, momentary (duration less than one second). Survey In addition, a survey of residents and decision-makers was conducted as part of the project. The results showed among other things that noise in conjunction with waste collection is the most important aspect for residents, followed by emissions and smell. The conclusion is that projects aimed at reducing noise and emissions are very important. Work environment During the project, an evaluation of the work environment was conducted that included interviews with the waste collectors to find out how they experienced the new type of vehicle. The most important and most widely appreciated improvement as experienced by the collectors was the reduced noise level from the electric-hybrid vehicle as opposed to conventional vehicles, since drivers of waste collection vehicles are exposed to noise from the vehicles all day. Reduced emissions were also seen as very positive among the collectors, although not to the same extent as for noise. An additional aspect of the work environment that was improved by using the new type of vehicle and a direct result of the reduced noise levels is safety. With less noise from the vehicle, the driver can be more aware of potential dangers from, for example, passing traffic at the collection point. 6
Production During the project period, the vehicles functioned well in production. Availability was around 97 percent. The vehicles were not out of commission more often than conventional vehicles. Repairs to the electric-hybrid parts constituted a very small part of the total repairs expenses. The fears that existed before the project started, such as that the batteries would not last for a whole day s work, were proven to be unfounded. Economy Table 1 shows the expenses for a conventional CNG vehicle and diesel vehicle, respectively, in relation to the electric-hybrid vehicle in percent. The following assumptions have been made: Investment The depreciation period is set to seven years with a cost of capital at 3.5%. The cost of capital included the assumption that the batteries would need to be replaced once during the life of the vehicle. Personnel The project has shown that the electric-hybrid vehicles can collect the same amount of waste as conventional CNG and diesel vehicles. The costing is based on manning of each vehicle with two people. Service and repairs Based on the information gathered during the project. Fuel Measurements during the project showed that the reduction in fuel consumption was between 20 and 40 percent. The costing is based on a reduction of 20 percent. Electricity Applies only to the electric-hybrid vehicles, and consumption was measured during the project. Other costs Refers to costs for motor vehicle tax, tyres, garage rental, insurance, etc. Cost Conventional Conventional categori CNG vehicle (%) diesel vehicle (%) Financial depreciation and capital costs 81 64 Personnel 100 100 Service and repairs 94 78 Fuel 125 125 Electricity 0 0 Other costs 100 107 Total 97 93 Table 1. Cost of a conventional CNG and diesel vehicle in relation to an electric-hybrid vehicle. The expenses on which the costing was based totalled 81 percent for a conventional CNG vehicle and 64 percent for a conventional diesel vehicle of the equivalent expenses for the electric-hybrid vehicle. However it is important to note that the vehicles in this project should be viewed as prototypes. If the vehicle had been mass-produced, in all likelihood the investment cost would also have been significantly lower. Fuel costs per km for a heavy vehicle are the same in Gothenburg irrespective of the fuel type (CNG or diesel). This is since the market price of CNG in Gothenburg corresponds to the oil price. For other expenses, the diesel vehicle is more expensive than the other two types of vehicle. This is because the motor vehicle taxes on this type of vehicle are higher than on CNG vehicles. Marketing and PR During the project, a number of marketing and PR activities were carried out with the aim of spreading information about the new vehicles and how they have been experienced. The target groups were decisionmakers in businesses and the public sector within the EU in waste management. The activities included press releases and press conferences, brochures and newsletters at various stages of the project. In addition, CLEANOWA was presented at a number of national and international conferences in the areas of waste management, the environment and transportation. Results and conclusions The CLEANOWA system has been a success and has produced valuable results. The main conclusion is that the system could very well be used on a large scale. The system leads to less noise and air pollution from waste collection in the urban environment. This in turn will lead to a better local environment and thus increased quality of life for residents and a better work environment for the waste collectors. The electric-hybrid vehicle provides the greatest benefits on collection routes with long stops. For this reason, the technology should be used primarily in urban environments or in other densely populated areas. CNG-powered waste collection vehicles were used in the CLEANOWA project, but the electric-hybrid technology could naturally be used on diesel-powered vehicles also. The electric-hybrid technology could also be advantageously applied to other working vehicles in densely populated areas, thus contributing to an even better urban environment. 7
Renova AB. P.O.Box 156. SE-401 22 Göteborg. Sweden. Phone +46 31 61 80 00. E-mail: renova@renova.se www.renova.se