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Unique, Patented Natural Gas Compression Technology for Driving Down Emissions

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Enhancing Fleet Resilience with CNG Vehicles and the GoFlo® Compressor

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Image of ambulance

Many fleet operators are seeking to “green” their fleets to reduce their carbon footprint and to reduce their emissions of regulated pollutants, such as NOX and particulate matter. Operators of emergency vehicles, such as police, fire, ambulance, and certain public utility vehicles, are no different. Having connected with managers of numerous emergency fleets, we learned that these essential vehicles present special challenges for switching from traditional liquid fuels, such as gasoline or diesel to cleaner alternatives.

The fuel challenges of emergency vehicles

Unlike many fleet vehicles, emergency vehicles do not have predictable daily use patterns, especially in terms of miles driven. Some days might require few miles, while other days require many more miles… especially during a major emergency in which such vehicles are most needed. This puts a premium on being able to oversize the fuel tank (including batteries, if an electric vehicle) without significantly increasing cost or refueling time. Traditional liquid fuels score well in this respect, while electric vehicles are poor. Natural gas vehicles (NGV’s) fall between these two extremes.

Another factor in determining the merit of a fuel for an emergency vehicle is ts refueling characteristics. It is hard to match the resilience and reliability afforded by traditional liquid fuels for use during major emergencies. It is not costly to store the required volume of liquid fuel in a simple tank. Furthermore, the energy and power required to transfer a liquid fuel from a storage tank to a vehicle is modest, so that it is reasonable to design a refueling system that does not require grid electrical power (that might not be available).  This pumping power could be provided by a modest standby generator (operating on the stored fuel), batteries, or, even gravity. And such liquid refueling system would conveniently be fast.

Up until now it has been problematic to find an alternative fuel solution for emergency fleets that affords this same combination of qualities as liquid fuel: freedom from uncertain grid electricity and fast refueling with no compromise in vehicle range. The availability of the GoFlo natural gas compressor changes this calculation. It now becomes possible to refuel emergency vehicles quickly simply by connecting to the very reliable natural gas grid. GoFlo is powered by natural gas and, thus, has no need for an electrical power source.

Rita Hansen, CEO of Onboard Dynamics speaking at the Green Transportation Summit & Expo about resilience of emergency fleet vehicles powered by natural gas

Providing resilience to an emergency fleet means storing a certain amount of energy that can be transferred to the vehicles.

Let’s assume that a fleet has determined that it needs an emergency supply of 1000 gallons of gasoline. If their vehicles average 10 mpg, this fleet has 10,000 miles of emergency fuel. If this fleet wanted to provide the same 10,000 miles of stored “fuel” for electric trucks via a central battery, it would require about 5,000 kwh of battery storage (based on trucks that require 0.45 kwh/mi). At current prices, a battery system of this capacity would cost between $2.5 and $5 million.  A CNG refueling system, based on the electricity-free, GoFlo compressor would cost a fraction of this amount without having to depend on the electric grid for power.

One unique characteristic of many emergency vehicle fleets is that they might need to be redeployed to a location other than their home base in the event of an emergency. Examples of such emergencies might be flooding, large wild fires, hurricanes, earthquakes, etc. Such redeployments are commonly required as a provision of “mutual aid agreements”. Redeployment of vehicles is not feasible if their fuel supply is not also re-deployable or otherwise locally available. The GoFlo compressor can uniquely facilitate such re-deployments, since the required natural gas supply is so widely and reliably available. The availability of the GoFlo compressor changes the calculus in being able to utilize CNG emergency vehicles in this way.

The GoFlo compressor is a game changer for managers of fleets that must be ready to serve the public, even in the event of emergencies and disasters. Clean and economical natural gas vehicles are now even more attractive for these operations.

Getting the Most from Your CNG Station Grant

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How can the GoFlo help reduce costs?

Many state, regional, and local agencies are offering particularly attractive CNG station grants to help overcome the higher initial cost of CNG vehicles, and associated refueling equipment, as compared to similar gasoline and diesel equipment.

Fleet operators are realizing that now is a great time to become a leader in the cleaner fuel movement and make the switch to using natural gas to fuel their vehicles and many factors are driving this movement:

  • Diesel and gasoline fuels appear to be entering another phase of increasing cost.
  • The environmental benefits of CNG as a fuel, in terms of both greenhouse gas and criteria emissions such as particulates and NOX, are more clear than ever.
  • Renewable natural gas is becoming increasingly available for those operators whose goals are carbon-negative fleets.
  • The performance, durability, safety, and resale value of CNG vehicles is no longer a concern, as documented by the experiences of thousands of fleet managers all over the US operating every sort of CNG vehicle.

With all these factors in favor of making the switch to CNG vehicles, what more does a fleet manager need to know before making the conversion decision?

When considering installing a refueling system for your CNG fleet, the initial cost, even if covered by a grant, is only a portion of the cost of your refueling system. Consider the cost for the energy to power the compressor. You will likely find that a compressor powered by natural gas, instead of electricity, will save you a lot of money not covered by any grant.

The GoFlo® natural gas powered compressor gives fleet managers who prefer to have their own “behind the fence” refueling system a new option to reduce operating costs even further.

How can the GoFlo® help reduce costs?

To be used as a vehicle fuel, natural gas must be compressed to 3600 psi (the US standard) for storage in the vehicle fuel tank. This compressed natural gas is referred to as CNG. Such high-pressure storage provides a good combination in tank size, weight, and cost providing utility comparable to liquid fueled vehicles. Traditionally compressors capable of providing such high-pressure fuel have used an electric motor to drive a multi-stage compressor.

Electrically driven compressors come with a number of inherent disadvantages:

  1. Installation cost can be high since the electrical utility service must frequently be upgraded to provide the required 3 phase, 430/480 volt power (sometimes greater than 100 amps).
  2. Operation during electrical power outages (critical for fleets such as utility, trash haulers, transit and school buses, first-responders, highway maintenance, ports, etc.) requires costly standby electrical generators.
  3. Operating cost for the required electrical power is surprisingly high, and ever increasing.

Usually, these disadvantages are not considered in the selection of a CNG compressor, since virtually all commercially available CNG compressors are comparable in these metrics because they are all powered by electricity and are all similar in their efficiency of converting electricity to mechanical power to drive the compressor.

But, in the case of a CNG refueling system that is funded in whole or part by a grant, one of these disadvantages becomes especially significant: the operating cost for the electrical power. While a grant might partially or fully cover the higher installation costs and backup generator associated with an electrically driven CNG system, virtually no grant will cover the higher operating cost of such electrically driven systems.

How important might this be? The cost of this electricity must be compared to the corresponding cost of natural gas consumed by the GoFlo compressor in producing the same volume of CNG. We will use costs corresponding to a typical site in Southern California to illustrate this cost tradeoff. (If you contact Onboard Dynamics, one of our staff members can walk you through a sample comparison for your own fleet yard.)

In conclusion, remember to consider the cost of energy consumption to power a station CNG compressor. You will likely find that a compressor powered by natural gas, such as the GoFlo, will provide you cost savings not covered by a grant.

When does it make sense to have your own CNG refueling system?

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When does it make sense to have your own CNG refueling system?

If you operate CNG vehicles from your own fleet yard and refuel at a public refueling station, perhaps you should investigate the savings you could realize with your own refueling station. The new and innovative GoFlo® compressor makes private refueling even more practical and thus lets you save even more from your investment in CNG vehicles.

National Average Retail Fuel Prices
*Clean Cities Alternate Fuel Price Report (Updated: April, 2018) https://www.afdc.energy.gov/uploads/publication/alternative_fuel_price_report_april_2018.pdf

The cost savings will vary based on characteristics of individual sites, but using some national averages will help size the potential savings. The national average price for CNG at publicly accessible stations was $2.21 per GGE (gasoline gallons equivalent) on July 17, 2018. The national average price for natural gas delivered to commercial customers was $4.36 per 1000 cu ft in June 2018. This converts to $0.545 per GGE. This difference between CNG price and delivered natural gas price is $1.66 per GGE and, less the cost of owning and operating a CNG refueling system, represents the potential cost savings from a private refueling system.¹

Drive down the cost of compression

Our company, Onboard Dynamics, refers to this cost of owning and operating a private CNG refueling station as the “cost of compression” and it has been our mission to drive this cost as low as possible for the greatest number of fleet operators. This cost of compression is like the cost of refining crude oil into gasoline: it is the cost of a process to convert a raw fuel (crude oil or natural gas) into something that can be used in vehicles (gasoline or CNG).

As we use the term, the cost of compression represents the direct costs of owning and operating a private refueling system. A more accurate and complete cost assessment would include the indirect labor and vehicle operating cost associated with the trip to the public refueling station. In our discussions with a variety of fleet operators (including waste haulers and bus operators) we have seen that this indirect cost can easily amount to $3.00/GGE or more.

System size and initial cost

When we speak of our mission as being to lower cost of compressing natural gas, we must stress the importance of system size and initial cost. Historically, private CNG refueling systems have only been cost effective for fleets requiring over 1000 GGE/day of CNG. But what about smaller fleets? Or the first few natural gas vehicles purchased by a large fleet operator? How do you get to 1000 GGE/day if there is not an economical solution for 200 GGE/day? Our belief has always been that a viable solution to CNG refueling must be cost effective at as small of demand as possible and that greater demand can be met, with even greater resiliency, by multiple modular units.

Based on the average costs used here, these two cost elements… the spread between the cost of natural gas itself and the typical public CNG price and the indirect cost of travel to a public refueling station … represent the opportunity to save several dollars per GGE.

Give us a call and we’d be glad to look at your particular site characteristics to assess how our GoFlo® compressor can help you realize these savings.

¹Taxes and tax credits can eat into or increase these potential savings. But, again, these are highly variable and site specific. We will ignore these factors here.

CNG Technology Keeps Improving

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CNG as a transportation fuel continues to grow steadily

CNG as a transportation fuel continues to grow steadily with an increase of 7.6% over the last 5 years and 8% since 1997.  The number of CNG vehicles has grown 5.3% since 2012 to 175,000 in the US.  The supporting infrastructure has also shown steady growth with public stations up 8.4% over the same six years.  That figure does not include any private fleet fueling stations.

 U.S Natural Gas Vehicle Fuel Consumption

Cost savings and emissions reductions are driving the increased use of CNG.  While the inherent volatility in oil prices will continue to make the exact advantage of fuel savings fluctuate, CNG fuel remains a very favorably priced alternative to conventional fuels.  Technology improvements continue to drive further emissions reductions, as well as operating efficiency and safety.  

Some fleet owners such as UPS look beyond just fuel costs and regard CNG as a component of their long term fleet management strategy to balance many different factors, including location, regional economics and emissions.

While various vehicle makes and models have come and gone, there are now more to choose from than ever in the medium to heavy duty categories.  DOE provides an easy-to-use interactive tool to look at options within 12 vehicle types from sedans to school buses and everything in between.  NGV America’s list focuses on heavy-duty vehicle manufacturers and modification companies.

CNG technology has come a long way since the 1930’s natural gas balloon vehicles of World War I era.  Recent technology improvements are more tailored to bringing CNG engine performance to the equivalent of conventional fuel engines, improve safety and achieve further reductions in emissions.

Reducing engine weight, simplifying systems, reducing the number of parts, advanced ignition and fuel injection systems, and downsized engines with higher boosting all contribute to better CNG vehicle performance.  In the medium and heavy duty classes, Cummins strives for zero emissions and FPT Industrial outline their technical improvements for more engine torque and power.

Exciting improvements are also occurring in NGV tank technology. CNG tanks made of composite materials are becoming less expensive, and, compared to traditional steel or aluminum tanks, are lighter in weight and require less frequent inspections and replacement.

Fueling technology improvements target safety and efficiency with Hexagon Composites improving connection safety and speed of fueling for heavy duty trucks.  Onboard Dynamics compression technology provides an alternative for small and medium fleet fueling locations.

These examples are not exhaustive but illustrate how CNG transportation technology is not just using a different fuel in a conventional fuel engine anymore.  Improvements in CNG transportation technology overall provide a competitive option with the added benefit of operating cost savings and emissions reductions.