If you were to ask a typical group of people to define a green truck, the vast majority would probably say that it is an electric hybrid or a natural gas-fueled truck. Both of these answers are correct in that a green truck can be defined as having a significantly reduced impact on the environment. However, the work truck industry has moved far beyond these technologies when it comes to being green. In addition to electric hybrids, today’s world of hybrids includes hydraulic, extended range, plug-in and work site. Battery electric vehicles fall into a unique category somewhere between hybrids and alternative-fuel powered vehicles, and are a viable option in certain applications.
In the world of gaseous-fueled vehicles, compressed natural gas is what most people really mean when they say “natural gas-fueled vehicles” – but this is only one of several viable options. Depending on factors such as fleet size, disposition, and drive / duty cycles, fleets also utilize liquefied natural gas and propane (autogas). In the foreseeable future, we will also probably see the use of di-methyl ether (DME) and hydrogen.
In the Beginning
It is probably safe to say that the green truck movement really started with the development of the High-Efficiency Truck Users Forum (HTUF) hybrid aerial truck around the turn of the century. Propane has been successfully used for many years as an alternative fuel, and there was some interest in the use of natural gas in the late 1990s as a result of increasing fuel costs. However, these applications never caught the public eye as being environmentally friendly. Conversely, the HTUF hybrids were extremely successful, primarily because the technology was a perfect match for the drive and duty cycles associated with utility aerial lift trucks, and received significant public exposure. This success led to a rapid expansion in hybrid truck development and some people came to view hybrid trucks as the ultimate answer to the rising cost of fuel and the need to reduce vehicle emissions.
Unfortunately it soon became evident that while hybrids perform very well in some applications, they are not suited to every vocational truck fleet application due to variations in drive and duty cycles. During the same time period, we saw a significant growth in the use of reduced emissions, low cost, and alternative fuels like natural gas and propane (autogas), and battery electric propulsion. Like hybrids, the use of these technologies can significantly reduce a fleet’s fuel costs in the appropriate applications. The combined success of hybrids and alternative fuels created a mindset, especially within the media and the general public, that a green fleet was by definition using hybrid vehicles or an alternative fuel. In reality, any technology which significantly reduces a fleet’s impact on the environment can be considered green.
Defining the End Game
The primary emphasis for developing the HTUF hybrid was to reduce the consumption of fuel which would, in turn, reduce carbon dioxide and criteria emissions. All viable alternative fuels also result in emissions reduction. While this an important objective, many fleets consider the ultimate end game associated with green technologies to be reduced operating costs.
Unfortunately, the use of hybrids and alternative fuels typically means significantly higher acquisition costs, and - in the case of some alternative fuels - significant infrastructure investments. If the ultimate objective is to reduce operating costs, the savings associated with long-term operation of a green fleet must not only recover the incremental investment, but also provide a viable return on the incremental investment. The ability of any green technology to provide this return on investment is directly connected to the individual fleet’s drive and duty cycles. Other factors, such as the concentration of vehicles in a given location and the operational impact of a given technology, also must be considered.
Burning Less Fuel
The direct cost savings associated with most green technologies accrues from using less conventional fuel or using a fuel with a lower cost per unit of energy delivered. A direct corollary of burning less fuel is fewer emissions regardless of fuel type, so burning less fuel is green regardless of the fuel used. So, a totally conventional gasoline or diesel powered truck can legitimately be considered green if it can be reconfigured to significantly reduce fuel consumption while still performing a given task. As far as I know, there is no legally recognized definition of how much reduction in energy is required to be considered green; overall energy demand reductions in the range of 25% to 30% are typically referenced.
All currently viable alternative fuels and other energy sources such as electro-chemical energy storage systems (read: batteries) have a lower energy density than conventional hydrocarbon fuels (gasoline and diesel). As a result, range limitation is often an issue when using these alternative energy sources. One way to address range limitation is to figure out a way to reduce overall energy demand associated while still accomplishing the required job. This takes us right back to the concept of using less energy to accomplish any given task.
The Concept of Sustainability
Technologies available to the fleet and/or operations manager to achieve improved operational efficiency fall into multiple categories. Each unique method of reducing total amount of energy consumed per unit of work accomplished can be referred to as “sustainable vehicle technologies.” By definition, a sustainable technology reduces the impact of an action on the environment and limits the depletion of natural resources.
There are literally dozens of ways to reduce energy consumed in conjunction with the operation of your fleet. Looking at the big picture, energy savings need not be directly associated with the operation of a vehicle. For example, you can reconfigure your shop operations to reduce heating and lighting loads. You can also reduce shop waste, utilize recycled materials in your operations, and recycle your own waste stream. Each act reduces total environmental energy demands which ultimately reduce energy costs and emissions.
When it comes to your trucks, you can increase direct efficiency in multiple ways:
- Reduce rolling resistance
- Reduce aerodynamic drag
- Optimize powertrains
- Limit incidental vehicle idling
- Improve power export efficiency (PTO applications)
- Reduce vehicle weight
- Improve vehicle utilization efficiency
- Driver behavior modification
Many technologies can be implemented with an investment significantly less than that associated with the use of hybrids and alternative fuels, making them a very attractive alternative for the fleet that wants to reduce operating costs on a limited budget, or a fleet with a drive/duty cycle not conducive to the use of hybrids and/or alternative fuels.
If you would like to discuss this, or any other fleet issue with the NTEA, call 800-441-6832