With natural gas vehicles (NGVs) estimated to emit 25% less greenhouse has emissions than diesel-powered vehicles, fleet managers are considering the change. This article outlines the practical implications and benefits for moving fleets to alternative fuels.
By Bob Wallace & Reb Guthrie
Many fleet managers and owner/operators are weighing their options when it comes to purchasing natural gas trucks vs. diesel trucks. The big question is "When it comes to diesel or natural gas trucks, which is best for my bottom line?"
If fleet managers and owner/operators want to make an informed decision about their business, it is crucial to understand the differences between diesel and natural gas trucks. A growing number of fleets have already made the switch to natural gas after weighing the benefits and challenges. Private waste companies such as Waste Management and Republic Services are buying thousands of new natural gas vehicles (NGVs), based mainly on the economics of switching.
However, the public sector is lagging behind private haulers in making the switch largely because governments have a harder time securing the capital needed to buy the new equipment. Yet some cities and other local governments are moving in the same direction as the private sector in order to generate the economic and environmental benefits that are available from compressed natural gas (CNG).Introduction
Everyday in every major city, town or community, one vehicle type, besides school buses, passes through every residential street - the waste/recycling collection truck. Refuse collection vehicles (RCVs) operate daily in various parts of every residential part of every city, collecting municipal solid waste (MSW), green waste, recyclables, food waste and bulk waste. In most cities or towns, these trucks are still powered by traditional diesel or biodiesel.
In the US alone approximately 180,000 refuse trucks operate and burn approximately 1.2 billion gallons of diesel fuel a year, releasing almost 27 billion pounds of the greenhouse gas, CO2. Every gallon of diesel fuel burnt emits more than 22 pounds of CO2.In the event a local CNG fuelling facility it not available, one will have to be designed and constructed
In the US, there has been increasing interest in fuelling waste and recycling collection fleets using alternative fuels, primarily either from CNG from the gas-utility grid, or in some cases from landfill or biogas (aka bioCNG) captured at their own waste processing facilities.CNG or LNG Fuel
There are two types of natural gas fuels - compressed natural gas (CNG) and liquefied natural gas (LNG). Each has its own advantages and disadvantages. CNG is the lower priced of the two fuels and is much more readily available. CNG requires somewhat more payload displacement for equal fuel capacity vs. LNG.
However, the disparity had been reduced in recent years due to lighter CNG-storage cylinders and more efficient cylinder configurations on the trucks. The other major challenges with LNG are the fuel delivery, storage and actual vehicle fuelling.
For the purposes of discussion, this article focuses on CNG, since it is a more readily available both in terms of fuelling facilities and vehicles, the abundance of infrastructure, and lower cost.Fuel Economy & Costs
Waste trucks have poor fuel efficiency, typically around three miles per gallon, which has been compounded in recent years since the price of diesel has hovered around $4+ per gallon for the last five years.
Currently, CNG is competitively priced with diesel. The price of a diesel gallon equivalent (DGE) of CNG has steadily fallen compared to the price of a gallon of diesel.
Although the market price of natural gas was fairly volatile in the previous decade, it has stabilised due to significant increases in discovery and production of natural gas in the US. It now appears the price of natural gas has decoupled from the price of oil and has therefore not been as volatile as gasoline and diesel prices. The expansion of natural gas vehicle (NGV) usage holds the promise of reducing carbon emissions, lessening dependence on foreign oil, and lowering fuel and transportation costs.
Viability of natural gas as a transportation fuel has grown partly because the availability of shale gas resources has dramatically expanded and gasoline and diesel prices have spiked. NGVs are also appealing because the high-pressured fuel system is sealed, so very little fugitive emission occurs during fuelling and use.
Natural gas trucks can save on fuel costs but the up-front costs are significant. The most costly element is installing a natural gas fuelling station, which depending on its size, can cost several million dollars to permit, design and construct.
An alternative to constructing a new fuelling facility is to locate a nearby facility that allows third-party access for fuelling. In addition, fleet maintenance facilities have to be upgraded to accommodate CNG fleet maintenance, which requires gas detection as well as improved ventilation to manage possible gas leaks that can be ignited through an inadvertent spark.
The trucks themselves can also cost between $30,000 and $50,000 more than their basic diesel counterparts. However the savings for operating NGVs add up quickly. A DGE of CNG costs less than $1.15 to produce, including the cost of the gas commodity, electrical power for system operation and a maintenance allowance .Landfill Biogas & Renewable Natural Gas
Fuelling a vehicle with food waste was a concept made famous by the movie Back to the Future in the 1980s. Now, almost 30 years later, what was once a futuristic idea has become a reality. In some places, waste trucks run on the methane captured from the same landfills where they drop off their payloads.
Biogas, also known as renewable natural gas (RNG), produced at locations such as landfills dairy farms, or anaerobic digesters can supply gas to onsite fuelling infrastructure for vehicles such as refuse haulers and dairy trucks. Bacteria breaks down organic waste to produce the methane, which is then filtered and compressed for use in the trucks as a vehicle fuel creating RNG.
There is equipment costs associated with refining RNG for use as vehicle fuel, which includes processes to remove moisture, CO, CO2 and heavier hydrocarbons. Once the RNG has been refined, equipment and installation costs for a fuelling station using RNG are similar to those for a fuelling station that is connected to a utility pipeline.
Increased use of CNG vehicles opens the door to use of RNG. The great news it that RNG is a fully sustainable fuel and with over 30% of municipal solid waste (MSW) being food waste and green material, refuse fleets are uniquely positioned to capitalize on a "closed-loop" approach, collecting and processing organic waste to produce RNG for fuelling vehicles hauling the same waste.
Producing RNG captures greenhouse gas (GHG) emissions from agricultural waste and landfills that would otherwise migrate into the atmosphere, turning a costly pollution problem into a revenue-generating product that serves regional climate goals. In fact, RNG has the lowest carbon intensity (CI) values of all fuels rated for California's Low Carbon Fuel Standard.
According to the California Energy Commission (CEC), CNG from landfill gas and dairy-digester biogas reduces life-cycle GHG emissions to 85–90% below those of diesel fuel, while biomethane derived from high-solids anaerobic digestion can reduce life-cycle GHG emissions to roughly 115% below those of diesel.
The use of landfill gas as a vehicle fuel is becoming more common as organisations seek to cut their greenhouse gas emissions and take advantage of the availability and sale of renewable energy. In July 2014, the EPA finalised the Renewable Fuel Pathways II Final Rule to identify additional fuel pathways under the Renewable Fuel Standard (RFS) Program.Benefits of CNG
The expansion of natural gas vehicles (NGV) usage holds the promise of reducing carbon emissions, lessening dependence on foreign oil, and lowering transportation costs.
Viability of natural gas as a transportation fuel has grown partly because the availability of shale gas resources has dramatically expanded and gasoline and diesel prices have spiked. NGVs are also appealing because the high-pressured fuel system is sealed, so little evaporative emission occurs during fuelling and use.
Cities, counties and states are increasingly requiring that CNG refuse trucks be used as a condition of granting solid waste and recycling collection contracts.
While California jurisdictions have been leading the charge, the town of Smithtown, NY also pioneered this approach in 2006, becoming the first locality outside of California to mandate use of CNG trucks for refuse collection.
The approach has since become commonplace elsewhere. Even in communities that do not mandate use of CNG trucks, proposing to use a CNG fleet can improve a firm's competitive position in the bidding and evaluation process, with the promise of lower contract costs for fuel, reduced emissions and lower noise pollution.Operational Assessment
In determining whether it is practical and cost effective to consider converting a waste truck fleet to CNG, it is necessary to perform the proper due diligence by reviewing the operations and fleet needs as follows:Existing vehicle requirements for conversion to CNG / fleet vehicle-replacement schedules; Typical fuel use per day including travel routes, mileage, stops, capacity by vehicle type; Maintenance capabilities including facilities operational requirements, location, and personnel knowledge and training; Expected growth in services, customers, etc. as related to future vehicle numbers and use; and Proximity to customers with the potential for CNG fuelled fleets. Feasibility of locating a CNG-fuelling facility at the fleet yard, including consideration of adequate space, electrical power, and vehicle circulation. Evaluation of fast-fill (fuelling 1-3 NGVs simultaneously within 5-10 minutes, similar to a conventional petrol fuelling sequence) vs. time- or slow-fill (fuelling the entire fleet simultaneously with individual dispenser hoses installed at NGV-parking spaces, typically over 8-10 hours each night).
The answers to these primary factors are critical in assessing the practicality of converting a fleet to CNG.Republic Services is another firm buying NGVs based on economics
Cost - Benefits Analysis
In addition to the due diligence collected from the fleet operational assessment, fleet managers should assess the qualitative and quantitative comparisons of using CNG for new RCVs such comparisons to include:Cost of new vehicles; Lead time between vehicle order and delivery; Cost of diesel fuel; Five and ten year spreads on a miles per equivalent gallon basis based on projected supply/demand of fleet use in the US of various fuels; Fuel tank capacity, fuelling frequency, and mileage; Expected vehicle performance in terms of productivity, number of stops, starts, unit life, speed, performance, acceleration, vehicle range, etc.; Emissions based on expected use of the fuelling options; Cost per mile comparison; Payload capacity impacts; Gross Vehicle Weight, weight difference and impact on route numbers or timing of routes; Noise generation comparison; and Analysis on issues stemming from the mounting of the fuel tanks to the body, specifically addressing: Height restrictions; and Tank serviceability by mechanics and required fall protection. Operational and Financial Impact Analysis
Conducting a operational and financial impacts analysis includes reviewing personnel (headcount) requirements for repairs, fleet maintenance, and operations of the fleet assuming vehicle replacement schedule for the next five and ten years with CNG vehicles, including the following:Expected service life of the vehicle Routine/scheduled maintenance requirements including timing and materials; Required maintenance including maintenance facility requirements/modifications and personnel; Vehicle inspection requirements (including fuel tanks) and licensing fee comparisons; Cost and availability of replacement parts, including if vehicle fuel type increases in use or is phased out of manufacture; Number and skill level of personnel for maintenance; Initial and ongoing training requirements for service and maintenance personnel; Comparison of cost of in-house maintenance and/or outsourcing maintenance; Modifications to the maintenance garage as needed to make the garage CNG-safe; Initial and ongoing training requirements for mechanics and drivers; and Identifying local private sector repair and service facilities and providers. Fuelling Site Analysis
The US Department of Energy Alternative Fuels Data Centre website offers a free alternative fuelling station locator for finding alternative fuelling stations near a specific address or ZIP code or along a route in the United States. It allows users to enter a state to see a station count and specific fuelling facility locations (see http://www.afdc.energy.gov/locator/stations/)
In the event a local CNG fuelling facility is not available, a fuelling facility will need to be designed and constructed. In this scenario, it is important to consider the following as part of the decisions as to where to site the facility:Location of natural gas distribution lines in relation to the planned CNG facility and requirements to adequately serve the compressors; Location of electrical service in relation to the planned CNG facility and the cost and requirements to adequately connect and operate the compressors; Footprint of the locations to house the entire solid waste fleet; Footprint of the locations to house required vehicle maintenance structures and the requirements and costs for those maintenance structures/changes to existing structures; Logistical comparison of each with respect to ingress and egress as related to CNG fuelling; Operational cost impact including any route modifications required of each CNG refuse trucks based on vehicle fuelling requirements; Operational cost impact including any route modifications of all non-CNG refuse trucks including vehicle fuelling requirements; Design-engineering and permitting requirements including timing; Estimated infrastructure costs; Maintenance and operational costs for the station(s) and related equipment; Useful life of major station equipment and estimated replacement cost; Consideration of developing a coop or shared-use CNG facility with nearby fleet(s), as well as consideration of the public sale of CNG as a revenue stream; Suitability of time-fill and fast-fill CNG station(s) and/or a combination thereof; and Should procuring for such services be required, estimating the timing for the possible design, permitting, and construction for all locations, including a temporary station (if applicable) needs to be considered.
If a fuelling facility is to be designed and constructed, it is necessary to determine a baseline for function and performance for the needed CNG fuelling facility, as required to meet the planned use.
Once the key design parameters have been determined – i.e. number of fast and/or time-fill dispensers, standard cubic ft. per minute (SCFM) capacity of the compressor system, compressor-redundancy levels etc. – site-specific configurations and conceptual equipment layouts will be prepared that account for variations in gas-supply pressure, total available space, and even shape of the space (perhaps a single duplex skid would fit better than two separate skids at a given site).
This would also include assessing cost and operational factors for fast-fill vs. time-fill solutions, such as reduced fuelling-labor costs for time fill, verses reduced dispenser costs and improved fuel-use tracking for fast-fill configurations.
Once the equipment configuration and conceptual site layout for two or three candidate locations has been established, that information can be used to prepare preliminary construction-cost estimates for the fuelling facility.
This needs to include site-specific allowances for ancillary factors, such as paving, fencing, lighting, supply-utility upgrades, and added sound-mitigation requirements.Grants and Funding
It is important to conduct research and identify funding and grant opportunities as well as any tax or government rebates or credits for which a specific fleet may qualify. Various incentives may be available in the forms of tax credits, grants, rebates and voucher-based vehicle price buy-downs which can further accelerate payback period for fleet conversions.
Along with Federal incentives, several states such as California, Colorado, Florida, Texas and Indiana offer strong incentive programs for purchasing vehicles that run on CNG. Other states offer incentives as well, and some states offer incentives for building CNG fuelling infrastructure.
The federal government has for several years provided for an excise tax credit of 50 cents per gasoline gallon equivalent (GGE) of CNG used as a transportation fuel to be claimed on tax filings, as well as a tax credit of up to $30,000 of the cost of building CNG fuelling infrastructure. The federal tax credits expired on the last day of 2014; however there is a high likelihood that during its current session,
Congress will renew these tax credits retroactive to the first of January 2015. Depending on the type and amount of incentives received, ROIs for fleet conversions to CNG RCVs can be reduced to just two or three years.Other Considerations
The recent discoveries of massive natural-gas reserves in the US are creating greater scales of economy in support of long-term planning and fleet conversions to NGVs. They are helping the US and Canada to break free of dependence on foreign oil.
According to the Environmental Protection Agency, NGVs typically emit 25% less greenhouse gases than diesel-powered vehicles. In addition, natural gas is lower priced than diesel, approximately $1.50 to $2.50 less per gasoline gallon equivalent (DGE), depending on whether the CNG is purchased at a retail location or is produced at a fleet's own facility. About 50% of new waste trucks and 25% of new buses in the US operate on natural gas. In several cities, all RCVs and buses are now running on natural gas, either in city collection fleets or contracted private-sector fleets.
While diesel prices have declined in recent months, fleet owners and managers need to take a long-term view about petroleum costs and fleet conversions to CNG. The US Energy Information Administration (EIA) has projected that natural gas prices will remain significantly lower than the price of petroleum for at least the next two decades and that natural gas prices will be less volatile than diesel fuel.
Fleet standardisation in terms of vehicle type, manufacturer, model, chassis, body and other specifications is an excellent way to gain greater productivity out of fleet operators, fleet maintenance, reducing spare parts inventory, and increased utilisation the fleet.
Bob Wallace, MBA is the founder and a principal of WIH Resource Group. Reb Guthrie is a principal and co-founder of Fuel Solutions.
Making a clean sweep with the Magnum
The key to successful road sweping is to get the job done effectively and efficiently in a single pass. For most road sweepers this is dependent on the consistency of the material being swept – and in the real world that simply doesn't happen.
Designers and developers at Scarab Sweepers have found that the solution is to build a machine that combines all the fuel savings and environmental benefits of a proven and reliable power system that drives both the truck and the sweeping mechanism, and then give it a hefty tweak with a high speed fan.
The result is that the most aggressive and unpleasant materials, such as hard-stuck, heavy mud, can be targeted, swept and sucked away into a spacious hopper, and the machine then immediately returned to its standard, cost-saving, high efficiency speed and power.
The Magnum has been developed to achieve the best possible performance at the same time as minimising running costs and reducing its impact on the environment. The high speed fan can be brought into service quickly and for the required time only.
The single engine Scarab Magnum will return fuel consumption rates of seven litres per operating hour, based on real operator experience rather than manufacturer's data, which can sometimes only be achieved under unrealistic, ideal conditions.
A hydrostatic gearbox is mounted in the chassis driveline of the Scarab and supplies hydraulic power to the sweeping and driveline systems. This system provides the Magnum with the ability to vary its' speed, and giving a drive similar to an automatic gearbox.
The Magnum requires a truck chassis of between 15 and 18 tonnes GVW. It has a wheelbase of 3260mm to 3900mm, length of just over 6 metres and a height of just over three metres, depending on the chassis selected.
The hopper's payload capacity is up to nine tonnes, with a water tank carrying 1800 litres as standard or 2500 litres as an option, and a diesel fuel tank capacity up to 150 litres.More Waste Management World Articles
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