Jeff Witwer, PHD, PE

The concentration of methane in the atmosphere is numerically quite low at less than 2 parts per million. However, methane is widely viewed as a potent greenhouse gas because of its global warming potential which is approximately 28 times greater than CO₂ on a weight basis. (Some sources claim an even higher multiplier.) Furthermore, atmospheric methane concentration has been increasing in recent years, as seen in the graph below, which is largely attributed to the ever-increasing production and use of natural gas. Other methane sources, including natural ones like swamps and geologic vents, might be larger, but are not growing as fast and are harder to control and mitigate.

According to the US EPA, over half of the methane released to the atmosphere due to the production and use of natural gas originates in the production phase where methane is released, or vented, usually in combination with other produced gases. This venting frequently occurs at smaller, dispersed wells where it is not cost effective to gather and clean the produced gases. Such venting also is frequently associated with wells developed primarily to produce oil where produced gases (also called “associated gas”) are essentially a waste product.

Using an accounting approach different from the EPA, the industry group ONE Future calculates a methane intensity to essentially measure molecules into a pipeline compared to molecules out of a pipeline. The purpose of this approach, as opposed to the more macro approach of the EPA, is to allow individual companies to benchmark and track themselves to promote continuous, publicly accessible improvement. Both distribution and transmission/storage companies using this approach report methane intensity scores of better than 0.1% in recent years (i.e., less than 1% of molecules are “lost” to the atmosphere).

The focus of the pipeline industry is to reduce this loss to an absolute minimum. And to do so, requires zeroing in on all possible sources of these losses.

Methane emissions from pipelines can be generally placed in 3 categories:

• Fugitive Emissions
• Emissions From Incidents
• Emissions From Venting

The causes, remedies, and environmental rules and regulations for each of these are different.

Fugitive Emissions

These are methane emissions that result from normal, designed-in, pipeline operation. Examples include:

• Minor seepage around compressor rod packing as it wears.
  A near-term solution to this release is more frequent maintenance of such wear components. A more permanent solution is new compressor technology, such as hermetically sealed compressors.
• On/off operation of pneumatic valves.
  We normally think of pneumatically operated devices as running on pressurized air. But more generally, the term “pneumatic” can be applied to any device driven by any pressurized gas. In the case of the pipeline industry, pressurized natural gas is commonly present, so it is logical to use this convenient supply for pneumatic power. Unfortunately, such use necessarily results in the release of methane into the atmosphere as valves are opened and closed. A solution to such releases is replacement of pneumatic valves with electrically driven ones. Note that such substitution can carry the risk of reduced pipeline reliability as the system becomes more dependent on electricity supply.
• Microscopic seepage through pipeline walls due to indetectable, small cracks.
  All pipes are subject to small leaks, especially as they age. These can be so small that they are impossible to detect, and they can certainly be so small that it is not “cost effective” to repair them (perhaps, unless there are fines or fees). To account for leaks of this type, a so called “emission factor” is commonly used (for example, leaks per mile) based on industry averages. Individual pipeline operators can use detailed surveys of their own particular pipeline systems to apply for lower factors.

Emissions From Incidents

These emissions are due to accidents or equipment failure. The pipeline operator did not intend for these releases to happen and will generally repair as soon as possible, especially since these releases can involve large flow rates of escaping gas.  Pipeline operators are always striving to minimize incidents (e.g., “call before you dig” campaigns), so solutions usually are associated with safety and maintenance programs.

Emissions From Venting

Vented releases are those that result from intentional acts by the pipeline operator. Examples include:

• Venting a compressor housing for maintenance or repair
• Opening and closing pigging launchers and receivers
• Blowing down a pipeline for repair, expansion, or decommissioning

Among all types of emissions, vented emissions are the ones that our current GoVAC® products address. These emissions are also the ones that give the greatest “black eye” to operators since they seem to occur by choice and could thus be avoided. Through the products and services provided by Onboard Dynamics and similar companies, the solution to our industry’s “venting” problem is at hand.

Reducing methane emissions from natural gas pipelines is a significant focus for environmental efforts, as it contributes to climate change. Improved monitoring, maintenance, and the use of new technologies, such as our GoVAC® system, are essential for mitigating these emissions throughout the natural gas supply chain. The natural gas industry will play an important role towards the energy transition as we find long-term solutions to our energy needs.

Jeff Witwer, PHD, PE

Jeff is the Technical Advisor/Co-founder of Onboard Dynamics. He is an experienced entrepreneur, having founded or co-founded two companies in the energy and software industries before co-founding Onboard Dynamics.

Over two thirds of the energy consumed in US homes, businesses, and industry is delivered in the form of either electricity or natural gas. Over the past several years there has become a growing interest in technologies to store these energy forms both to facilitate the increased use of intermittent, renewable energy sources, like solar and wind, and to increase energy resiliency in the face of global energy disruptions and natural disasters and storms, such as hurricanes, fires, and extreme weather events (e.g., the Texas freeze of 2021).

The technologies and costs of storing either electricity or natural gas are very different. And these differences will shape the roles that each electricity and natural gas play in achieving our dual goals of decarbonizing our energy system with renewables at the same time we seek to increase energy supply resiliency.

The primary way that electrical energy is stored today is in batteries and, indeed, grid-scale battery systems have become less expensive in the recent past. According to the US Energy Information Agency (EIA) such storage systems have fallen from over $2000/kwh in 2015 to just under $600/kwh in 2019 (latest data); however, there are concerns that this rapid decline will not continue, and, indeed, could reverse, due to shortages of key materials. We will ignore this uncertainty for this discussion. In addition to batteries, electricity can be indirectly stored on the grid via pumped storage facilities that pump water up to reservoir at a higher elevation then release the water to run through turbines to a reservoir at a lower elevation. Such systems can be economically attractive but are severely limited in scalability due to siting and environmental limitations. Other approaches, such as compressed air storage and lifting large weights and recovering the potential energy, are being investigated but have not yet proven to be more cost effective than batteries.

Using the same EIA data source, there was 1,688 MWH of battery storage capacity in the US at the end of 2019. In that year, total electricity production in the US was 4,128 TWH. Combining these numbers shows that in 2019, about 0.00004% of annual electricity production could today be stored in grid-system batteries. The EIA forecasts that the battery storage capacity will increase by 10X, or to a level of about 0.0004% of annual electricity production, by 2023.

The scale of these numbers illustrates that the main use of battery storage systems is to compensate for the short-term changes that can occur when variable solar and wind power sources are added to the grid. Longer term, seasonal storage is not practical with today’s technologies.

In contrast to battery storage of electricity, natural gas storage is currently practiced, both in the US and overseas, on a relatively large-scale basis primarily by utilizing naturally occurring storage reservoirs, such as impervious salt caverns, aquifers, and depleted natural gas fields. Relying on natural geologic features means that a facility to store natural gas costs between $5 million to $6 million per billion cubic feet.  On an energy equivalence with electricity, this corresponds to about $0.02/kwh for the storage facility.

According to the EIA, US storage capacity for natural gas was 9.26 trillion SCF. In that year, EIA reports the consumption of natural gas was 30.28 trillion SCF. In other words, in 2021, just over 30% of annual consumption of natural gas was available from storage resources. Referring to the difference in cost to store a unit of energy as electricity versus storing that unit in the form of natural gas ($600/kwh vs $0.02/kwh) explains why natural gas is the medium of choice to store large volume of energy for long (e.g., months) duration.

This large difference in the cost of the “storage vessel” also explains why there is such strong interest in producing gaseous fuels, like hydrogen and e-methane, from renewable wind and solar sources. The cost of long-term storage of gases can be so much lower than the cost of “storing electrons” in batteries that the additional cost to produce these gases, even from renewable electricity, might be justified. This is the goal of many inventors and researchers.

Of course, there is more to this storage puzzle because natural gas and electricity do not exist in isolation in our energy system. Because electricity is so often produced by burning natural gas in a power plant (or, for example, reacting natural gas in a fuel cell) stored natural gas also helps manage the unpredictable variations in solar and wind supply to the grid, while it also ensures a seasonal fuel to compensate for lower solar production during the winter. It also ensures a reliable supply of fuel to thousands of standby generators in critical applications, such as hospitals, water plants, and communication facilities throughout the country in the event to natural disasters.

In order for our country to continue to gain all these benefits from natural gas, it is essential that we maintain an extensive and safe infrastructure of natural gas storage, transmission, and distribution. Without these assets It will not be possible to achieve our energy decarbonization and resiliency goals.

Jeff Witwer, PHD, PE

Jeff is the Technical Advisor/Co-founder of Onboard Dynamics. He is an experienced entrepreneur, having founded or co-founded two companies in the energy and software industries before co-founding Onboard Dynamics.

Those of us involved in the US energy ecosystem find that our days are filled with a never-ending stream of new challenges such as increasing energy costs, supply chain issues, more stringent environmental regulations, narrowing reserve margins, increasing interest rates, and so forth. Can you imagine what is like to be in the corresponding energy ecosystem in Europe, where all these same forces are in play …. plus, there is a war going on next door, with threats of eminent curtailment in nearly 30% of your energy supply? Such is the situation faced today by nations of the European Union (EU).

While an ocean might physically separate the US from the EU, this same ocean will not isolate us from what is happening in the European energy world. In this article, we’ll look at actions that the EU has immediately taken to update its energy strategy in response to the war. Then we’ll discuss how these actions might affect the US and lessons that we might learn to enhance our own strategies as we move forward in this new world.  

Those who are not familiar with the process of creating and implementing energy policy within the EU will be surprised at the formal, comprehensive, bureaucratic, and centralized process they follow. In contrast, here in the US, it seems that our energy policy can be pivoted frequently by a wide variety of relatively isolated single events or actions, such as executive orders, court rulings, or the actions of a single Senator. The EU energy policy is largely driven by a series of constantly evolving policy statements, plans, and regulations that bind all EU members to a variety of actions.

Before Russia initiated the war in Ukraine, the most recent, comprehensive EU energy directive was the “Fit for 55” plan presented July 14, 2021. The focus of this plan was to describe policies and actions that the EU would take to reduce greenhouse gas (GHG) emissions to 55% of their 1990 levels by 2030, on a path to be “climate neutral” by 2050. Again, it can be hard for us in the US to envision how detailed and comprehensive these EU plans can be, but in the illustration below, each cell represents highly detailed plans for component pieces of the energy puzzle providing a clear picture of the detailed content of the Fit for 55 plan.

As recent and comprehensive as the Fit for 55 plan was, it did not anticipate the impacts on energy of the Russian invasion of Ukraine. For example, an important tool used in the plan to achieve near term GHG reductions was to use natural gas to replace coal for electricity generation. Before the war, about 40% of natural gas used in the EU came from Russia, so almost overnight, this key element of the plan was invalid.

In a matter of weeks following the invasion of Ukraine, the EU released on May 18 a revision of Fit for 55, REPowerEU, whose goal is “to rapidly reduce dependence on Russian fossil fuels and fast forward the green transition”. Just like Fit for 55, the REPowerEU impacts virtually every element of the energy ecosystem: natural gas, biomethane, wind, solar, hydrogen, infrastructure (both electric and gaseous), electric vehicles, synthetic fuels, conservation, international trade, work force training, emissions trading, finance, critical materials, etc. To achieve its more aggressive goals, REPowerEU calls for the EU to spend an additional 210 billion euro (~$225 billion at today’s exchange rate) between now and 2027. This updated plan has 4 main themes:

• Re-double energy conservation measures (especially buildings);
• Diversify energy supplies (e.g., more LNG from US and other secure sources);
• Accelerate clean energy transition (e.g, increase renewables from 40% in 2030 to 45%, largely via more offshore wind and hydrogen);
• Guide investments and regulatory reforms (e.g., streamline permitting)

To this analyst, one of the most interesting things we in the US can learn from REPowerEU is to better understand “What does it look like to transition a wealthy, industrialized population of hundreds of millions away from ‘fossil gas’”. The EU is trying to make this transition in a few years. Some in the US say we should do this within the next few decades. Can we in the US watch and learn from the EU, relying on our abundant domestic supply of natural gas to provide us a clean, lower cost transition period?

An important, near-term priority of the REPowerEU plan, and shared by many in the US gas industry, is a very aggressive stance toward renewable natural gas (RNG) from bio sources (animal wastes, landfills, and water treatment plants). Increasing RNG production is especially appealing in the EU since it directly replaces Russian gas as a “drop in” replacement.

In studying either the Fit for 55 or the most recent REPowerEU plan, the element that I believe would stand out to most readers is the important, essential role of hydrogen in the EU’s future energy system. The analysts and planners in the EU seem to understand that moving and storing massive volumes of energy in gaseous form has advantages that cannot be matched by electricity (and batteries) alone. The following chart shows that the EU planners expect that use of hydrogen (along with associated synthetic methane, aka e-gas) will surpass fossil gas by the early 2040’s.

Furthermore, both recent EU plans call for ADDITIONAL gas pipelines to move gaseous fuels both within the EU and from marine import terminals. These terminals would initially import fossil gas from US and the Middle East transitioning to green hydrogen from solar-rich regions (e.g., Africa, Spain). The EU energy planners understand that carbon-free, gaseous fuels have advantages over electricity due to costs of transportation and long-duration storage. Far from viewing new pipelines as a way to “lock in” use of fossil gas, the EU takes a longer view and recognizes that pipelines are an excellent way to carry renewable energy. A map of one such plan, including its new pipelines and connections to North Africa and the Middle East, is shown below:

It should be noted that this scenario of upgrading gaseous pipelines to be compatible with, and ultimately carrying, either methane or green hydrogen has also been proposed by SoCal Gas for its service territory. In addition, a Houston-based consortium has proposed a similar green hydrogen ecosystem for southeast Texas, the H2Houston Hub, that would be based on expanding existing hydrogen production, transportation, underground storage, and chemical engineering expertise. 

As interesting as what the EU plans say explicitly is what they do not say but hold open for future options. A prime example of this is the role of nuclear power. Just as in the US, nuclear power is a somewhat of a 3^rd rail in that some feel it is essential while others view it as deadly. The most recent REPowerEU seems to hedge this issue. Nuclear power could play a complementary role with hydrogen as its 24/7 availability would lower its cost by operating electrolyzers continuously instead of only when the sun was shining or wind blowing. Furthermore, low-cost hydrogen is key to the production of green synthetic fuels, including e-methane (for existing pipelines) and synthetic aviation fuels. It is interesting to note that, again motivated by the war in Ukraine and the associated desire to become more energy secure, Japan is moving to re-open its nuclear power plants.

There is much for us to learn, both as an industry and as a nation, as the EU moves to free itself from Russian gas. Those who are agile will find opportunities with both environmental and business benefits. The US can learn a lot from the EU about how to navigate the future energy challenges we’ll be facing as a nation. 

Jeff Witwer, PHD, PE

Jeff is the Technical Advisor/Co-founder of Onboard Dynamics. He is an experienced entrepreneur, having founded or co-founded two companies in the energy and software industries before co-founding Onboard Dynamics.

Getting a spacecraft to Mars, we’ve done that. But getting home, especially with passengers onboard? Those who study such a mission have concluded that it is not feasible to carry enough fuel (along with cargo) to make the return trip possible. And a one-way ticket is not likely to provoke enough commercial interest. The only solution seems to be to manufacture a very energy-dense fuel and oxidizer (oxygen) on Mars itself. Fortunately, Mars has CO₂ and water. Using solar and/or nuclear energy and Martian water, both hydrogen and oxygen (required for the rocket, but also personally useful) can be produced on-site via electrolysis. The hydrogen could then be combined with Martian CO₂ to produce methane, which is an ideal fuel for the return trip. An excellent description of this whole system as envisioned for the SpaceX Starship, including why methane is the best fuel even for the outbound trip to Mars, is found here.

If it is attractive to make methane on Mars from zero-carbon energy because it is so energy-dense, might we use methane in this manner to carry and store energy in a future, net-zero energy system on Earth? Many researchers feel that methane constructed from atmospheric CO₂ and water, so-called e-methane, could, for a variety of reasons, boost our transition to net zero. Let’s take a closer look at e-methane, sometimes also called synthetic methane.

We usually think of methane as a source of energy because it is a major component of natural gas, in which form it supplies about one third of our nation’s energy. But in our evolving “net zero” energy system, methane is likely to play an equally important role as a carrier and storehouse of renewable, non-fossil and nuclear energy. As an energy carrier, e-methane is like electricity in that it is a way to move energy from one location and source to another location and use. An obvious difference between the two ways to move energy is that electricity is carried in conductive wires while methane is carried in pipes.

As an energy storehouse, e-methane is unique because it does not require costly and inefficient conversion to/from another form as does electricity when stored in batteries (electrical to chemical for storage, then chemical to electrical for use). We’ll discuss this storage role and associated technologies in a future article. Here, we will focus on carbon-neutral and carbon-negative ways to produce e-methane.

If methane did not occur “naturally” (e.g., “natural” gas), its invention would likely be heralded as one of the greatest of all time. Why is this? Because methane is an extremely effective and flexible way to “carry” energy from one location and source to another location and use.

We all know that electricity can be made from a variety of energy sources (coal, nuclear, solar, wind, etc.), at a variety of costs and environmental impacts. We are generally less familiar with the alternatives for producing methane, other than from its most familiar source, natural gas.

Why use methane to carry energy

Let’s start with looking at why one would want to use methane to “carry” energy that originates from a non-natural gas source.

• There is already an extensive pipeline infrastructure in place to move methane long distances. It is a key national asset, like our highway system and electrical grid.
• This in-place pipeline infrastructure currently distributes methane to millions of end-uses.
• Pipeline movement of methane is uniquely energy efficient and safe.
• Because the gas pipeline infrastructure is essentially all underground, it is highly immune to damage by natural disasters , providing an essential resiliency to our energy system.
• The underground gas pipeline system imposes minimal visual impacts on the communities it serves.
• Methane in pipelines provides an inherent storage capability to accommodate fluctuations in energy supply and demand. In contrast, electricity must be generated precisely when it is demanded to avoid instabilities in the grid.

Of course, gaining these benefits from a methane transmission/distribution system requires associated diligence. Pipelines can release methane, a known greenhouse gas, if damaged by accident or poor maintenance. But this risk is like that created in our other, primary energy transmission/distribution system, the electrical grid, which can cause fires if lines are downed by accident, poor maintenance, or natural disasters. It is unlikely we can have the benefits of reliable, abundant energy without assuming some level of risk and responsibility.

Molecules vs electrons in distributing energy

The above considerations suggest that there are advantages in distributing energy in the form of molecules (e.g., methane), instead of considering only electrons (electricity). But before considering how we can produce a molecular energy carrier we need to understand that methane is not the only molecule that can carry zero-carbon energy. The hydrogen molecule, H2, is another way to bundle zero carbon energy from, for example, solar or wind energy, to transport from one location and source to another location and use. A typical model of such a scenario is shown below where renewable energy is converted to electricity, which is used in an electrolyzer to produce hydrogen from water. This molecular hydrogen can then be moved in gaseous form via pipeline or high pressure tank or liquified via refrigeration for transport by ship or truck. At an end use, the hydrogen could be used to produce electricity via a fuel cell, burned to produce heat or fuel a truck or plane, or in a variety of chemical processes to produce any number of other materials and chemicals, including e-methane.

Producing e-methane from hydrogen can be done by methanation (also referred to as the Sabatier reaction), an established industrial process that reacts hydrogen with CO₂ as follows:

The CO₂ could be from any source, but in a clean energy cycle, it would be removed from the atmosphere or a flue gas. By sourcing the required CO₂ in such manner, the produced e-methane could simply be burned at the end use in the same type of combustion appliances as traditional natural gas burning equipment (with slight modifications to reflect different thermodynamic properties). This hydrogen production/use scenario results in a net-zero energy cycle. If the CO₂ were captured at the end use (using, for example, an established process such as an amine wash or any of a variety of new ones under development), the overall process would be carbon-negative. In this scenario, we are essentially using a single carbon atom to “carry” four hydrogen atoms. At the end use, the four hydrogen atoms are combined (i.e., burned) with oxygen to produce water and the same amount of CO₂ that was captured in the initial methanation step…. a carbon neutral energy process.

Several Reasons to Use E-methane as a Hydrogen Carrier

• E-methane is completely compatible with existing natural gas transportation infrastructure and uses. This includes both LNG and CNG production and uses.
• In a transition scenario, e-methane can be mixed with natural gas in any ratio, while it is generally accepted that pure hydrogen can only be mixed with natural gas up to about 20%.
• Methane is liquified at a warmer temperature (-162oC) than hydrogen (-253oC), therefore requiring less energy. This greatly reduces the cost of e-methane liquification and transport compared to liquifying hydrogen.
• E-methane actually contains more energy by volume than either compressed or liquified hydrogen itself, again improving economics in many uses.

A Belgian company, Tree Energy Solutions, has proposed a complete energy production and transport system to enable Germany to replace Russian natural gas with e-methane produced by solar energy from sunny regions of the world… essentially carrying sunlight to Germany 24/7/365 via e-methane. The e-methane component allows this supply system to grow and merge in parallel with existing and near-term LNG transport and natural gas distribution infrastructure. Over time, the percentage of e-methane would be increased to result in the evolution of a zero-carbon, gaseous energy system.

A new energy architecture that not only helps preserve our current world but takes us to a new one: e-methane has a promising role. And just as we need a robust, reliable electrical grid to realize the distribution benefits of electricity, we need a robust, reliable methane pipeline network to realize the distribution and storage benefits that e-methane will provide us. And the good news is that it is already in place.  

Could it be that yet another technology from our space program, just like solar photovoltaic cells and fuel cells, would be key to enabling our zero-carbon future?

Jeff Witwer, PHD, PE

Jeff is the Technical Advisor/Co-founder of Onboard Dynamics. He is an experienced entrepreneur, having founded or co-founded two companies in the energy and software industries before co-founding Onboard Dynamics.