Floating on Hopium

The Folly of H2 Blending

Hindenburg Disaster, 1937

What the H(2)?

Elemental hydrogen is the lightest, most abundant substance in the universe. It comprises about 75% of normal matter, and is fundamental to the sunlight and water that gives life to earth. However, occurring naturally as a gas at room temperature, hydrogen (H2) is also highly combustible, and must be handled with care. Failure to do so tends to result in catastrophe, such as the infamous 1937 immolation of the Hindenburg dirigible, which went down in flames on attempt to dock at Naval Air Station Lakehurst, New Jersey. The crash, indelibly imprinted on the minds of all who witnessed it, tolled the death knell for the burgeoning airship industry.

In 2020, the European Union embarked on a new, equally risky, attempt to wrangle hydrogen into submission, piloting projects to blend H2 with methane in existing natural gas pipelines. The initiative was introduced as an intermediary decarbonization method, as H2 emits water vapor when it is burned, and therefore meets policy targets aimed at reducing CO2 emissions (Never mind that water vapor is itself a greenhouse gas (GHG), but that’s another story…).

Some small scale blending projects are already underway. For example, Netze BW claimed it successfully tested a combination of 30% H2 and 70% methane in the natural gas transmission grid in a limited area of Baden-Wuerttemberg in Southwest Germany, serving a utility property and 26 adjacent households (this project is particularly cavalier in ignoring the 20% maximum hydrogen threshold that is recommended according to field experts). The press release further stated that the demonstration showed “the infrastructure is fundamentally capable of transporting the eco-friendly fuel.” In another project in Salerno, Italy, a 10% admixture of H2 showed safe and effective fuel delivery to two industrial facilities. Most recently in May 2024, the Portuguese government offered its first tender for hydrogen blending in the public gas network.

We’re On the Pipeline to H-

Despite these early, isolated achievements, dangers lurk in longterm, scaled-up hydrogen blending. The most serious of these are pipeline embrittlement and hydrogen leakage. The chemical properties of H2 lead to breakdown in the mechanical strength of steel over time. This can eventually cause corrosion of the pipeline, allowing flammable methane and hydrogen to escape into buildings and potentially cause explosions. Furthermore, because H2 is a much smaller molecule than methane, it can leak more insidiously through microscopic cracks that previously went undetected. One study found that blended H2 leaks at about three to five times the rate of natural gas.

Comparing infrastructure designed for hydrogen to natural gas pipelines highlights the above-mentioned safety concerns. Dedicated hydrogen transport pipelines have been used for decades in Europe and the United States for industrial purposes. These pipelines are relatively small in diameter (3.9-11.8 in/100-300mm) with thick, reinforced steel walls. Natural gas pipelines are much wider, between 16-48 in/41-122cm, with thinner walls. With such vast variability in design requirements between the two network types, it is not difficult to imagine the plethora of problems that may arise from introducing hydrogen into the natural gas system.

A 2023 report published by non-profit Food & Water Watch articulated several glaring concerns with hydrogen blending, particularly in the U.S. The American natural gas pipeline system is on average very old, with 70% of lines older than 25 years, and 10% older than 80 years. This “rickety” network is already prone to methane leaks, “contributing to an estimated 659,000 leaks from the gas distribution system in the US annually.” If the strength of current pipeline stock is weak enough to allow methane escape, hydrogen escape would be exponentially greater.

Moreover, hydrogen is 14 times as flammable as natural gas, and it does not necessarily require heat to ignite. Mere exposure in sufficient quantities to static electricity, friction, and electrical fields can cause a fire or explosion. Because hydrogen burns very hot, much hotter than natural gas, and travels at much higher velocity, it can burn backwards into pipelines and create high-pressure explosive conditions that can destroy entire buildings. Also, unlike natural gas, which is infused with artificial odorants for leak detection, hydrogen is colorless, odorless and undetectable.

Optimal hydrogen transport should also occur at higher pressure than natural gas to prevent gaseous escape. In the U.S., H2 pipelines have operated safely at or below 1,000 psi since the 1930s, equivalent to the upper bounds of the natural gas transmission network. What has not been thoroughly assessed is the ability of distribution lines to deliver hydrogen locally to individual homes and businesses. As a study by the National Renewable Energy Laboratory points out, natural gas distribution lines step down operating pressure to only 0.25-200 psi.

Another under-researched topic is the ability of appliances designed for natural gas fuel to function properly and safely with blended H2. One recent study found that new gas boilers built to the most recent code can operate normally with up to 20% hydrogen blending without significant modifications. Other research suggests that older, and poorly maintained gas appliances would not be safe to operate with any amount of hydrogen fuel. Because the estimated useful lifetime of boilers can be up to 25 years, there is likely a significant installed base of older units still operating in the U.S. building stock, putting large swaths of the population at risk from hydrogen-related accidents in their homes.

Putting the “H” in Hype

A more fundamental question lies at the heart of the hype over hydrogen: does it even have the capacity to be a significant driver of CO2 reduction? To answer this question, it is first necessary to discuss how H2 is synthesized. In its 2020 Hydrogen Strategy, the E.U. laid out a pathway to decarbonizing H2 stock. Currently, for industrial purposes and for blending projects, most hydrogen is made from natural gas — this is the substrate that the E.U. (and U.S.) plans to use as the main resource during the short and medium term. This is obviously problematic from an overall carbon reductions perspective, because even if the blended hydrogen reduces CO2 to the end user, it does not affect the emissions of primary energy sources.

However, over a longer period, the goal is to convert electricity using renewable resources (wind and solar) into H2 through electrolysis (so-called “green hydrogen”). The diagram below depicts the possible pathways of H2 synthesis and integration into the pipeline grid, as planned by Southern California Gas (SoCalGas).

Source: SoCalGas

Electrolysis works by splitting water into oxygen and hydrogen atoms with electricity. This is an energy-intensive process that delivers an efficiency rate of about 70-80% for the most common and commercially available systems (alkaline electrolyzers). While designs yielding >80% have been demonstrated, they are relatively expensive and some are still in the prototype phase. When including the losses from thermal inefficiencies during hydrogen electrolysis, it is estimated that the process requires about 53 kWh of electricity to produce 1 kg of H2. By comparison, the electricity consumption for the average U.S. household over the course of a whole day is only 29 kWh.

In addition to thermal inefficiencies, the low density of hydrogen means that more of it must be supplied to the end user than its natural gas counterpart. About three times as much hydrogen is required to produce the same amount of heat as natural gas. So, even under ideal conditions of limited inefficiencies, this fundamental discrepancy in fuel density sets the upper bound of carbon emissions reductions to 7%, using current technologies.

The correlative of low CO2 reductions capacity resulting from hydrogen blending is high consumer energy bills. In order to scale up production, power plants will have to modified for hydrogen processing, and natural gas pipelines will have to be hardened to avoid the calamitous scenarios discussed previously. A study by German think-tank Agora Energiewende found that combining H2 into Germany’s natural gas pipeline system could raise consumer gas utility bills by as much as 33% by 2030.

“H”oping for a Miracle

Ever the intrepid follower of bad European energy policy, California has recently thrown its hat into the hydrogen-blending (circus) ring. In March, SoCalGas, with support from the Public Utilities Commission and the Investor-Owned Utilities, announced “a series of projects to demonstrate that blending clean hydrogen into the natural gas system is a safe and effective way to reduce greenhouse gas emissions, improve air quality and begin to scale up hydrogen as laid out in California’s climate [plan].” Unfortunately for the rest of the country, what happens in La-La Land usually doesn’t stay there. And hydrogen blending is the ultimate pipe dream.

Oh, the humanity!

Electrically yours,

K.T.