Energy saving options for fleets

July 22, 2014
‘Hybrid’ vehicles and alternative fuels are being developed to allow businesses to protect the environment and operate more efficiently.

Energy efficiency is a cornerstone of operating a business in a more environmentally friendly manner. My series on “green vending” has explored energy efficiency as it applies to machine operations and office/warehouse operations. In this final installment, I will explore energy efficiency as it relates to vehicle power and vehicle fuel, both of which are aspects of fleet vehicle operations.

Before continuing, let me note there are other aspects of vehicle operations that are important, both to environmental concerns and business efficiencies. Vehicle maintenance is an area that should be high on every operator’s list of priorities. Efficient routing is another aspect of managing the fleet efficiently. Other articles have addressed these aspects of vehicle operations. This article will address vehicle power and fuel issues.

A promising option for vehicle power involves hybrid technology. A “hybrid vehicle” is a vehicle that uses two or more distinct power sources to move the vehicle. The term most commonly refers to hybrid electric vehicles (HEVs), which combine an internal combustion engine and one or more electric motors.

A hybrid system uses an auxiliary battery pack and an integrated electric motor/generator situated between the vehicle’s engine and transmission. The generator is used to capture energy normally lost to heat during braking. Once this energy is captured and stored in one of the batteries, it helps activate the electric motor connected to the truck’s engine during periods of acceleration and high load, thereby reducing overall fuel consumption. While there have been medium-duty trucks on the market, there is research to develop a system for heavy-duty trucks.

Plug-in Hybrid Vehicles

Plug-in hybrid vehicles (PHEVs) will be unlike current models that do not rely solely on electric power. Instead, PHEVs will be designed with advanced battery packs that enable electric power exclusively. Most PHEVs will be equipped with a supplemental gas engine, should the vehicle run out of power before reaching its destination. PHEV vehicles are expected sometime in late 2010 or early 2011.

A hybrid electric drive system vehicle combines a primary power source, an energy storage system, and an electric motor to achieve a combination of emissions, fuel economy, and benefits unattainable with any of these technologies alone.

Many state governments already offer incentives for transit agencies that incorporate cleaner, more efficient technologies into a bus fleet.

Hybrid electric drive systems are a good option because they use less petroleum-based fuel and capture energy created during breaking and idling. This collected energy is used to propel the vehicles in normal drive cycles. The systems’ batteries supply additional power for acceleration and hill climbing.

Hybrid electric vehicles costs are not well documented at present.

Future: Alternative Fuels

Looking at fuel options, experts predict fleet operators will have flexibility in choosing cost-effective energy efficient solutions for their delivery vehicles. The Alternative Fuel Vehicle Institute (AFVi) is working to develop products and processes necessary to deploy alternative energy sources.

Apart from the various ways promoted for fueling vehicles, the one offering that is “fuel-agnostic” is hybrid power-train technology.

Given the federal government’s fickle history with tax incentives, and the cyclical nature of fuel prices, timing will be a critical factor in making the financial case for any of the alternatives. Yet ultimately, it may not be the bottom line that drives the purchase decision, but rather, consumer and political pressure. With that in mind, savvy managers must “get up to speed” on the various alternative fuel options and where each might fit in their fleet.

Alternative Fuels emerge

Conventional diesel fueled commercial trucks have ruled the roads for decades. Despite the fact that exhaust emissions from diesel engines have been significantly reduced, conventional diesel may not remain the fuel of choice as other options are being considered. Alternative fuel options include biofuel, biodiesel, and natural gas.

Biofuel is a flexible fuel that involves a blend of 85 percent ethanol and 15 percent gasoline marketed as “E85.” The ethanol in E85 is derived from a starch-based process that has not been widely adopted since the starch comes from corn which is a commodity with cyclical price fluctuations. As a result, E85-powered vehicles have not been as popular as previously anticipated.

E85, with ethanol derived from corn, often considered too price volatile for fleet reliance, is being redeveloped using a more advanced process involving the structural mass of plants (such as cellulose, hemi-cellulose, and lignin).

Plant-based, as opposed to commodity-based, ethanol is termed cellulosic ethanol. Cellulosic ethanol is derived from such abundantly available raw materials as switchgrass, miscanthus, and wood chips that are comparatively inexpensive to harvest and have been shown to reduce greenhouse gas emissions.

A major concern with this biofuel, however, is the complexity of the fermentation process necessary to produce the ethanol.

U.S. Department of Agriculture funding and additional tax incentive programs for purchasing ethanol-capable vehicles are expected to help ignite the supply and demand for biofuel commercial vehicles. Ethanol burns cleaner than gasoline, thereby contributing a lower level of pollutants.

Biodiesel for diesel engines

Biodiesel is a non-petroleum-based fuel that can be used alone or blended with conventional petroleum diesel (petrodiesel) in unmodified diesel engine vehicles. When used in a blended mixture, the percentage of biodiesel in the fuel mix dictates its labeling.

For example, a “B20” mix denotes 20 percent biodiesel and 80 percent petrodiesel. Biodiesel fuel, produced as a derivative of processed organic vegetable oil, most often has served as a petroleum-based fuel additive.

The most popular organic sources for the production of biodiesel are rapeseed and soybean oils with soybean being the most preferred ingredient.

Alternatively, animal fats and fish oils can also be used in fuel production. Unlike crop-based ethanol, vegetable or animal derivatives have little other use, thereby creating less fluctuation in product cost; supply, however, remains somewhat unpredictable.

Biodiesel fuels are associated with such environmental benefits as reduction in greenhouse gas emissions, deforestation, and pollution. A major concern for biodiesel storage is the need to maintain a clean supply.

Natural gas needs modified engines

Natural gas, also referred to as compressed natural gas, is considered among the most practical of alternative fuels. A conventional gas vehicle engine has to be modified to create a natural gas vehicle (NGV).

With a huge delivery infrastructure covering most population centers already established, natural gas offers a realistic, widely available alternative fuel.

Although most natural gas is still considered fossil fuel, it contains much less carbon than petroleum fuels. Natural gas can also be derived through organic processes, making it highly appealing. It is important to note that conventional diesel engines can be adapted to natural gas, and can deliver comparable performance results to the diesel version with far lower emissions. Some currently available natural gas engines have already been certified to meet the 2010 exhaust emission regulations.

Natural gas does create the need for a slightly larger vehicle fuel tank. Tax incentives coupled with price differences between natural gas and diesel can result in a possible payback period of 18 to 24 months.

Liquefied natural gas

An alternative is liquefied natural gas (LNG). LNG is a non-toxic, non-corrosive, and non-carcinogenic alternative fuel primarily used in heavy-duty vehicles. LNG is produced by cooling natural gas into a liquid at -260°F and storing it in double-wall, vacuum-insulated pressure vessels. Like compressed natural gas, LNG produces fewer emissions and offers fuel economy comparable to conventional fuels.

Ultra-low sulfur diesel fuel

Ultra-low sulfur diesel fuel can provide emission levels equal to standard petroleum products. The challenge with diesel fuel is that it tends to cost more than regular gasoline and therefore is expected to provide about 30 percent better fuel economy to justify its use as an alternative fuel. Diesel engines can often run on some biodiesel blends without modification. A special blend of diesel is termed Fischer-Tropsch Diesel.

Also known as a gas-to-liquid fuel, this form of diesel is created when a gaseous fuel is converted into a liquid and refined to make diesel or gasoline. Interest in this fuel is increasing due to its ability to reduce emissions and its compatibility with advanced emission control devices.

Vehicle idling affect costs

Energy efficient driving practices also make a difference. To keep their cabs at a comfortable temperature, heavy-duty truck drivers often idle the engine at an average of 1,400 hours annually, wasting a significant amount of fuel each year. Efficient truck technologies designed to help reduce or eliminate engine idling are highly desirable. By doing so, not only will firms save money on fuel but also reduce tailpipe emissions.

As mentioned at the outset of this article, vehicle maintenance is also important in managing the fleet as efficiently as possible.

Efficient vehicle fleet management can be a big part of an environmentally friendly vending/OCS operation. In combination with sustainable business practices and energy efficient vending machines, better fleet management will allow an operator to optimize energy use. In doing so, the operator is also able to help customers better manage their own environmental “footprint.”

For more information, contact:

Alternative Fuel Vehicle Institute, 702-254-4180,

National Biodiesel Board, 202-737-8801,