Leveraging Existing Gas Infrastructure for Decarbonization
The American natural gas delivery system spans approximately 2.6 million miles. This system represents trillions of dollars in investments over more than a century. On the coldest day of the year, this system delivers triple the energy the electric grid does on the hottest day. How can this massive asset be leveraged to boost decarbonization efforts?
There are many tools the gas delivery system brings to the table. No individual tool is a panacea – any or all can be part of the solution.
The first tool to consider is renewable natural gas (RNG). A carbon neutral fuel harvested from feedstocks including landfills, farms, and wastewater treatment plants, RNG is one of the easiest decarbonization strategies to implement because, being a natural gas molecule that behaves like all natural gas molecules, it requires no changes to the existing system. Analysis from the American Gas Foundation has identified plentiful sources of supply for renewable natural gas. The challenge for the industry will be to harness such sources at scale in a cost-effective fashion. Fortunately, even a relatively low percentage of RNG in the supply of natural gas can achieve significant overall reductions in the system emissions profile, with major climate benefits.
Next, it’s time to talk about hydrogen. There are two main ways to use hydrogen in the gas system: hydrogen blending, and dedicated hydrogen infrastructure. Utilities like Hawai’i Gas already blend up to 15 percent hydrogen into their fuel mix. Still, each local gas system has its own unique characteristics, and identifying the ideal hydrogen blend percentage for a given system is a matter of local study. With the Biden Administration’s announcement of seven regional Hydrogen Hubs and an expected $50 billion in investment in clean hydrogen, and with the success of numerous hydrogen pilot programs by America’s gas utilities, the process of adding more hydrogen to the fuel mix can begin in earnest.
Dedicated hydrogen infrastructure can take two forms. The first is new infrastructure, such as pure hydrogen pipelines from hydrogen hubs to industrial customers. There are other projects in the work that minimize how much new infrastructure is needed, while maximizing the utility of existing infrastructure. One company working in this space is Modern Hydrogen, which uses a process called pyrolysis to convert natural gas into hydrogen at the point of use. The value proposition is summed up well by a quote from Tony Pan, CEO and Co-Founder of Modern Hydrogen: “Our biggest value is speed of decarbonization, because we can skip infrastructure changes. Instead of changing all their pipes to become compatible with pure hydrogen, utilities can add our box at the end of the pipe, and the box strips out the carbon (C) as a solid out from the natural gas (CH4) molecules, leaving only clean hydrogen (H) for the end user. Then we sell and permanently sequester that solid carbon in roads.”
The proposition that the easiest way to transport hydrogen is to simply transport natural gas instead is an intriguing one. Lindsey Motlow, a Senior Research Associate and Physicist on the Sustainability and Energy Transition team with Darcy Partners, effectively summarizes many of the potential advantages of this approach and the progress being made on implementing it. “The Preliminary Acceptance test and implementation of Modern Hydrogen’s methane pyrolysis technology with Northwest Natural represents a pioneering milestone with distributed pyrolysis technology directly integrating with an operating gas system. Methane pyrolysis produces what is known as “turquoise” hydrogen; it is a hydrogen production pathway with the potential of low-to-negative carbon intensity. This hydrogen production method takes advantage of existing asset bases and workforces by use of hydrocarbon feedstock. Given the engineering and cost hurdles associated with large scale hydrogen production, storage, and transport, the commercial maturation of distributed “turquoise” hydrogen presents a compelling solution for on-site decarbonization, especially to customers connected to existing natural gas infrastructure.”
Last but certainly not least is finding ways to improve energy efficiency. Doing the same amount of work with less energy by ensuring that the gas delivery system is as tight as possible and the homes at the end of it are highly energy efficient is the low hanging fruit of decarbonization. America’s gas utilities spend $4.2 million per day on programs to help customers, particularly lower income customers, afford energy efficient home upgrades and appliances. This has the additional benefit of saving low-income customers money on their energy bills, making it an essential part of any decarbonization strategy.
No one can predict which pathways to decarbonization will be most effective. However, the numerous options available and being pursued by America’s gas utilities will allow all ideas to be tested, with the local utilities able to opt for those that work best for their own systems and customers.