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Do we need to purchase your bus, or can we continue using our current bus vendor? The Opbrid Bůsbaar is designed to be easy for any bus builder to add to their electric or hybrid-electric bus. Ask your bus builder if they have fast charging yet, and if not, mention the Bůsbaar. We will be happy to work with them to meet your needs. Our goal is not to lock you into a particular bus, but to enable practically any bus manufacturer to offer fast charging. In this way, we can focus on making the Opbrid Bůsbaar charging station better and better, and the making of buses to the experts - the bus manufacturers themselves.
Does the station require 3-phase (400V) or single phase (240V) electricity? Three phase. You can choose how much power will be suitable for the route, from 100kW to 240kW (or possibly more, depending on the battery size). The Schaefer chargers we use are forced air cooled, rated to -25 to 75 degrees C temperature, and automatically lower their output when over heated.
How much power can be transferred, and how far will the bus go?
The Opbrid Bůsbaar itself has a very high power transfer capability, as it uses components from heavy electric rail. We anticipate that it is easily capable of handling 700 A at 800 V, for a power of 560kW. Typically, this is much more than is needed, 200-240kW should be sufficient in most cases. If you have a 240kW charger, then you can transfer 20kWh of power in 6 minutes. This is enough to run a typical 12 meter bus for 12-18km, by which time the next charging stop should be reached.
Should we choose a fast charged Hybrid, or a fully electric bus?
Either one can be greatly enhanced with fast charging. While we recommend a fast charged hybrid for reliability reasons, there may be compelling reasons for you to go all-electric. A fast charged hybrid needs smaller batteries than a fully electric bus, and can always revert back to hybrid mode (diesel) if there is any problem with the electrical supply, weather, traffic jams, or just someone illegally parked under the charging station!
A fast charged all-electric bus can run all day with smaller batteries than the equivalent electric bus that only charges at night. Smaller batteries mean less up front cost, less weight, and more room inside the bus for passengers. Additionally, having chargers at the end of the route spreads the electrical load more evenly geographically than if you have a central garage where all buses charge.
How hard is it to install a Bůsbaar charging station, what is involved?
A typical installation requires a concrete pad for the charger housing and bases for the Bůsbaar poles. Underground ducting to bring power lines to the charger, and ducting to bring the DC power lines to the Bůsbaar poles. Your electrical power supplier also needs to bring sufficient AC power to the site. Once this is ready, installing the Bůsbaar only takes one or two days, since everything is already been tested and is ready to run. We can supply instructions for your technicians to perform the installation, or you can hire us to do it for you.
Does it also work for buses doing multiple stops that are much less than a minute (8-10 seconds per stops every 5-8 minutes)?
No, charging at each stop isn't worth the investment - lots of charging infrastructure for not much charging. It is much better to use the high power Opbrid system and charge at the end of the route. It is best if the bus has time at the end of the route to charge for 5-8 minutes, then you only need one or two charging stations, one at each end of the route, thereby lowering your infrastructure costs tremendously. Charging time depends of course on the route and scheduling. However,if the bus is also a hybrid, then if the driver doesn't have time to charge (perhaps due to traffic), he can continue on indefinitely using the diesel generator. Typically about 5 to 8 buses can share a charging station (one at a time!).
Is there any detrimental impact of 200 kW charging on the electrical grid or bus electrical system? Does it require special consideration on behalf of the utility company or the bus manufacturer?
The utility should be consulted, as they may have more capacity at some places than others. 150-250kW is not that huge a load, a small apartment building will consume this (think about 60 3kW air conditioners). The chargers have power factor correction for close to unity power absorption. The high voltage system on the bus is completely isolated from the rest of the bus electrical system and chassis.
What are the typical maintenance costs involved?
The charging station requires very little maintenance, just periodic inspection. The Bůsbaar itself is very durable and practically maintenance free. Likewise the pantographs on the roof are designed for life on the top of trains, and only a yearly inspection and greasing is required.
Is there any way to measure how much fuel we are saving?
All systems can be monitored remotely, including fuel consumption and electricity consumption (typically from the bus itself). The Bůsbaar contains a secure industrial computer that may be optionally accessed by the operator.
How can we make sure our drivers are using the chargers and not relying on the diesel backup generator?
There are various ways, from incentives to penalties. One possibility is to lower the performance of the bus when it is using the generator, so the drivers have a physical incentive to use electricity from the grid instead of petroleum. Another way is to force electric only operation within the city center using GPS.
Can the batteries be used for Vehicle-To-Grid (supply energy back to the electric grid)
While they cannot provide energy back to the grid, one of the advantages of having a backup diesel generator is the ability to forgo charging if the grid is overloaded. The utility can provide a signal to either the bus operator, or directly to the charger to either slow down charging, or stop it completely for some time period.
How long is the battery life? How much does it cost to change the batteries?
This depends greatly on what type of batteries you are using and their size. The AltairNano and Toshiba Lithium Titanate batteries should last the life of the bus, whereas Lithium Phosphate batteries may need to be replaced every few years. Remember that heat is the enemy of Lithium batteries. Each cell is monitored for voltage, balancing, and temperature, and this information can be sent over the web to be monitored remotely. Don't worry, you will know if there is any problem with the battery long before it becomes a problem.
We are often asked about retro-fitting existing buses as well. Here are some answers based on our experience with E-Traction and Hybricon in Umea, Sweden: Can the Opbrid/e-Traction system be retro-fitted on a regular diesel bus or does the bus have to be already a hybrid bus? Yes. For example, the buses in Umea, Sweden were originally Volvo 7700 diesel buses. e-Traction removed the diesel drivetrain and fitted their wheel motors, added batteries, backup generator etc. They have also done the same for the VDL Citea in Rotterdam as shown at Opbrid.com. Both are modern low floor city buses. The e-Traction wheel motors are particularly well suited for low floor buses since they fit perfectly in the space of twin rear tires on a ZF rear axle. Also, the traction electronics are built into the wheel motor itself, freeing up even more space.
What are the advantages and disadvantages of retro-fitting?
Retrofitting is a very interesting solution because you get double the ecological effect of buying a new bus, since the old diesel bus is gone from the city. If you just purchase a new bus, the old one will continue polluting for years to come! On the other hand, an older bus may have other problems that may need to be corrected during the retrofit. Also, if you retrofit a brand new bus, this may void part or all of the warranty. However, we offer a warranty on the parts we deliver.
What are the costs of the Opbrid/eTraction system
Currently the costs are fairly high due to the very high quality, advanced technology, and low volume. These will come down over time. However, if you make a comparison over the life of the bus, you will find that even with today's prices of diesel, the overall cost of the operating bus will be about the same as diesel. However you gain many advantages, such as zero pollution, very low noise, low CO2, better comfort, and more predictable costs. Essentially, you are buying your fuel up front at a fixed price in the cost of the batteries and electrical system - no more "fiscal emergencies" down the road due to unexpected fuel price hikes. Your riders will appreciate a more stable fare price! Also, in comparison to other electrification schemes such as subways, trolleybuses, and trams, the infrastructure costs of the Opbrid system are extremely low.
What modification are needed to be done to a bus to install the system? what are the costs involved?
The diesel engine, transmission, and rear axle are removed, and the new axle/wheel motor assembly bolted in place. This replaces a standard ZF rear axle exactly. There is no transmission or differential. Friction brakes are included as backup to the regenerative braking of the wheel motors. The rear tires are "Super Single" tires instead of the old dual rear tires.
Depending on the bus model, some small structural changes may need to be made to accommodate the diesel generator/auxiliary pump module. This is installed with a modular slide-in system for easy maintenance. The batteries are mounted on the roof. This is not so difficult, as the battery pack is relatively small, and balanced by the low center of gravity of the wheel motors. A fair amount of cabling and connections need to be made. The Opbrid pantographs mounted on the roof as well. Central computer and control system mounted in the driver area. The Air Conditioner will likely need to be replaced with an all-electric one instead of engine driven. It's best to focus on a small number of bus models to amortize the work needed for the first one, or use one of the two models that e-Traction has already done. It might be a very good idea to send a crack team of technicians to us to learn everything, and do the first two buses, then bring that knowledge back home.
How long does it take to retrofit one diesel bus and set up the charging stations per route?
The charging stations are very quick to set up once you have sufficient 3 phase power at the site. You will need an enclosure (small structure) to house the charging electronics. Installing the Opbrid Busbaar is similar to installing two street lights.
Retrofitting takes probably about 6 months for the first two, especially if they are different mechanically than the ones already completed (VDL Citeas and Volvo 7700). After that, it depends a great deal on your own team, and making sure you order parts sufficiently in advance. Some components have fairly long lead times. However, it should be possible to do a bus retrofit in two months once everything is streamlined.
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| Last Updated on Monday, 21 November 2011 13:55 |
