Air quality in many major cities is poor. High levels of particulates, nitrogen oxides, sulfur dioxide and other air pollutants, and noise, are a threat to human health. One reason for this is the large number of cars, trucks and other vehicles that are in motion around the clock.
In addition to contributing to air pollution, all vehicles powered by fossil fuels also emit carbon dioxide. But there is a lot happening in the automotive field with new generations of vehicles that are fuel efficient and cleaner compared to older vehicles.
Garbage trucks are a special class of vehicles. They are often dispatched in the early mornings to backyards and alleys. But conditions for effective waste disposal in older urban areas are often not very good. (See related article “The Rubbish Vacuum“)
There is hope for the future. A collaboration between Volvo Trucks and waste company Renova resulted in the world’s first complete hybrid garbage truck.
“Hybrid refuse trucks use electricity or diesel for propulsion and electricity for the loading and compression, a combination that makes it unique,” says Christian Kallerdahl, press officer at Renova.
Reduced environmental impact and better working conditions
During most of its working day, a garbage truck stands still while it loads and compresses waste. This generates noise, atmospheric emissions and consumes fuel. A garbage truck travels short distances. The highest fuel consumption occurs when it starts to drive and reaches 20 km per hour.
Hybrid garbage trucks offer several advantages by using an electric motor during the above operations, reducing fuel consumption by about 30 percent compared to a conventional truck.
A hybrid truck has two separate drive trains: one for gas (or diesel) and one for electricity. Drivelines can be used separately or together. The various sources of power can be used where they are most fuel-efficient. In practice, this means that the electric motor is used at low rpm and the diesel engine at higher rpm. Electric power yields high torque from the start, is quiet and makes for emission-free loading and compression.
These trucks have electric power steering and refined battery management systems that optimize battery performance. Refuse loading and compression are completely electrical and with the help of a plug-in compressor is charged via the grid. While a hybrid truck offers many environmental benefits, the one drawback is that they are still more expensive than conventional vehicles.
“Less noise and less emissions also creates better working conditions for the operators,” says vehicle development manager Lars Thulin. “Early developmental work with our garbage trucks showed that noise reduction increased safety because the driver can quickly draw attention to passing traffic.”
Renova and Volvo Trucks’ initiative has produced a ripple effect. In addition to the hybrid garbage trucks that roll in Sweden, these are now being tested by Veolia Environmental Services in central London. Veolia handles much of the garbage in London. Further tests are being performed in Paris and Rotterdam.
Focus: Vehicle environmental performance of vehicles
“We have purposefully focused on greening our means of transport,” says Kallerdahl. “Altogether we have 174 heavy vehicles and 37 of them are powered by gas. We have 16 garbage trucks with hybrid electric technology and in 2010, we launched Sweden’s first garbage truck powered by biodiesel and biogas. It is a conventional diesel garbage truck (meta-diesel) with the Euro 5 standard, which has been converted so that it can be operated even with gas. The result is a highly energy efficient vehicle that consumes 25 percent less energy than a traditional garbage truck running on CNG. The car is powered by biogas (70 percent) combined with RME (rapeseed methylester, 30 percent). The use of RME leads to a two-thirds reduction of greenhouse gases compared to regular diesel fuel. We currently have 10 such vehicles with more to come.”
“Since the spring of 2011, one of our trucks runs on liquefied biogas. With meta-diesel and liquefied gas (LNG), the truck can drive up to 800 kilometers on a tank and with very heavy loads of up to 35 tons. With this technology, even heavy trucks driving longer distances can be environmentally adapted.”
“I’d also like to mention that nearly 100 of our trucks are Euro 5-rated and fueled with RME. The drivers are trained in eco-driving and garbage truck routes are added by using a computerized logistics program to obtain the best choices,” concludes Kallerdahl.
This article was published in June 2011