Onboard Dynamics

Unique, Patented Natural Gas Compression Technology for Driving Down Emissions

Jeff Witwer, PHD, PE

Natural gas: villain or savior?

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Those of us working in the natural gas ecosystem have recently seen numerous articles calling for the elimination of natural gas production, transport, and use in our country because it is not “clean enough”. This is partly due to methane releases from leaks and the maintenance projects that repair such leaks. At the same time, there is a growing awareness by many others that to achieve our national goal of being “carbon neutral” by 2050, we must have a robust, leak-free gas distribution system to:

  • Compliment and supplement renewable energy sources
  • Eliminate coal use
  • Exploit new forms of zero-carbon and carbon-negative gases, such as hydrogen and renewable natural gas

An excellent report documenting this essential role of our gas distribution system was published in late April, 2021 by the Center for Global Energy Policy at Columbia University, entitled Investing in the US Natural Gas Pipeline System to Support Net-Zero Targets. The essential role of our natural gas distribution system is summarized by a brief statement from its executive summary:

Studies by energy agencies, universities, and the industry that model future US natural gas consumption consistently show continued use of natural gas for at least the next 30 years, even in scenarios where the country achieves net-zero targets by midcentury. There is no quick replacement for gas in the US energy mix. And for many of the needs natural gas currently meets, the eventual replacement may be zero-carbon gaseous fuels (e.g., hydrogen, biogas). These fuels may play a significant role in supporting reliability and making the energy transition more affordable—but they, too, will require a pipeline network for efficient delivery to markets and end-users.

As we say in our internal discussions, if the plumbing in your house has leaks, you do not stop using water. You fix the leaks. Onboard Dynamics has introduced the GoVAC™ Flex pipeline evacuation system as a novel tool to aid in fixing such natural gas pipeline leaks. New technologies such as ours, combined with improved remote sensing tools, will ensure that natural gas, and the pipelines that deliver it, will be available to help meet our challenging national climate goals.

As We Better Understand the Challenges of “Complete Electrification”, Improving Traditional Energy Supply Systems Becomes Even More Important

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During the past few years, we have seen growing interest in the concept that in order to achieve “net zero” carbon emissions, all end use energy should be delivered via electricity. This electrical energy can then be converted to many end use requirements without the release of greenhouse gases (GHG) at the end point. This logic has been applied to virtually every energy demand, from transportation to buildings. Possible carve outs might be some industrial applications that require large quantities of high temperature heat (steel and cement making) and long-distance air travel. These specialized demands might be met with a “green” fuel like hydrogen produced from renewable sources. The reasoning behind this approach has been that we “know” how to make carbon-free electricity via renewable energy technologies, like solar photovoltaics and wind turbines. (Some would also include nuclear power.) These electrical generation technologies are sufficiently developed that there is little associated technical risk in their expansion. And we have seen major cost reductions in the past couple of decades that should continue into the future. While leaving open some issues like industrial heat and long-distance air travel, electricity has seemed to many as a strong foundation to move aggressively against ever-growing GHG emissions.

A recent report by the International Energy Agency, The Role of Critical Minerals in Clean Energy Transitions, adds new realism to the challenges of achieving such an “all-electric” future. This detailed analysis points out that most of the technologies essential to an extensive conversion to electricity, such as photovoltaic systems, batteries, electric motors, and expanded transmission lines, will require much greater volumes of select minerals (such as lithium, nickel, manganese, cobalt, rare earths, aluminum, and copper) than required by our current, fossil-fuel intensive system. For example, an electric car requires about 5 times more of these minerals than a conventional automobile. A land-based wind turbine requires nearly 7 times more of these minerals than would a natural gas power plant of comparable output. A photovoltaic power system would require about 4 times more of these materials. Additional examples of mineral requirements for many of the key technologies are shown in the following chart from this report. (Note: In making these estimates for mineral requirements, the IEA took into account projected technology improvements that should reduce the need for some materials, such as cobalt required per kwh for batteries.)

Aggregating demand for these minerals across all the required electric technologies causes 2040 demand to increase by 42x for lithium, 21x for cobalt, 19x for nickel, and 7x for rare earths. Other minerals require similar growth, as shown in the chart below. The IEA report documents that around the world, it takes on average at least 16 years to develop a new mine. Having enough mineral supplies to achieve electrification goals will be extremely challenging.

Compounding the challenge of increasing mining and processing capacity of such materials is the fact that most of these minerals are currently sourced (mined and/or processed) from countries, such as China, Myanmar, the Democratic Republic of the Congo, Russia, and Mozambique, that many do not view as reliable trading partners around whom to build a durable, resilient next-generation energy system. Some of these countries also have less strict environmental standards than the US and other western nations, so expanding mineral extraction and processing in these locations can have negative environmental and health, and safety concerns. Experiences learned during the recent pandemic with critical medical equipment, such as PPE and ventilators, have made us all aware that a durable ecosystem/supply chain is essential to ensure social safety and security.

To further illustrate the size of this challenge, a recent article in the Wall Street Journal reports that major mining companies producing “technology metals”, such as copper, cobalt, and lithium are not currently investing enough in new production to even replace current production …. let alone increase it.  

The analysis provided by the IEA essentially shows that transitioning to an all-electric energy economy is essentially replacing a fossil fuel intensive energy system with a mineral intensive one. Drilling and refining are essentially replaced by mining and processing. Some unreliable trading partners are simply replaced with others with similar concerns. There is no “get out of jail” pass to side-step these challenges.

We do not need to turn our backs on efforts to increase electrification to reduce greenhouse emissions. But we’d be wise to retain, improve and de-carbonize traditional energy supply systems at the same time we seek new options. Reading the IEA report should be considered an essential part of understanding the risks and challenges we face in pursuit of our long-term energy and environmental goals.

The Untapped Opportunity of Smaller Sources of Methane

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The Untapped Opportunity of Smaller Sources of Methane

Most who have studied the challenges of a clean, low-carbon, and economical energy supply system agree that methane, produced either from wells or bio-sources (e.g., dairies, landfills, and water treatment plants), will play essential role in the decades ahead. A key challenge in realizing this opportunity is the fact that many of these diverse  methane supplies are from sources whose production rates are so low that it can be cost-prohibitive to provide two essential steps for commercial use:

  • Cleanup and conditioning of the raw methane mixture from either a well or bio-source. Methane from many important sources can contain various impurities, such as moisture, CO2, nitrogen, H2S, etc. These impurities need to be removed to produce fuel-grade methane that can be transported in a cost effective manner.  A variety of proven technologies exist to remove these impurities, however most are costly at smaller scales.

  • Transportation of clean methane to a viable market. When the volume of methane is large enough and/or the transport distances long enough, pipelines are a cost effective, safe, and clean way to transport methane. But when a pipeline cannot be justified, transportation of methane to market can be problematic due to its low energy density.  Again, numerous non-pipeline options exist, such as compressing the methane into CNG, cooling it into LNG, or converting it into a liquid fuel (such as methanol or dimethyl ether (DME)). Again, the challenge with these processes is their cost at modest scale.

Two examples will illustrate the size of this opportunity if the challenge of scale for cleaning and transport could be resolved:

Dairies

1000 cows can produce 50 to 100 mscf/day of RNG

There are 42,000 dairies in the US, while the RNG Coalition reports that less than 40 dairies produce RNG (renewable natural gas, or clean methane). Current dairy RNG projects will typically have over 10,000 cows, while the average dairy has only 187 cows. A dairy with 1000 cows could produce between 50 and 100 mscf/day of RNG. From these numbers, one can see that there would be an opportunity for thousands of systems to recover RNG from dairy farms alone, if these systems could be made cost effective at smaller scale.

Oil and Gas Wells

In 2017 646,000 mscf/day of methane was vented or flared from oil producing wells.

According to the EIA, at the end of 2017, there were 991,000 producing oil and gas wells in the US. In this same year, 236,000 million scf (646,000 mscf/day) of methane was vented or flared from producing wells, largely because it was not cost effective to clean and transport methane from the smaller and more remote wells. Worldwide venting and flaring has been estimated to be about 4 times greater than in the US, largely due to less stringent environmental laws outside the US.

These numbers suggest that there is both a business opportunity and an environmental need for thousands, if not tens of thousands (depending on the achieved cost), of modest scale systems that can clean and make available for transport distributed sources of geological and bio-derived methane. The companies that develop such systems will see strong success in the coming years. 

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.