Hydrogen is an abundant and clean burning gas, so it’s little wonder that many energy professionals consider it the key to powering the sustainable, net-zero economy of the future. The very abundance of hydrogen molecules has given rise to an array of options for producing it as an energy source. Charting a course for hydrogen that avoids unintended consequences will be a challenge, but a recent analysis indicates the hydrogen economy is closer than it seems.
The hydrogen economy is already here
The hydrogen economy is often referred to as a fixture of the future, but the fact is that hydrogen is already ubiquitous. Fertilizer, food processing, refinery operations, toiletries and medicines are among the chief uses for hydrogen today, in addition to its use as a rocket fuel.
Black & Veatch, a global consulting, engineering and construction company, took a closer look at the present and future uses for hydrogen in a recent white paper titled Hydrogen 2021: The Path to Net Zero Becomes Clearer.
As a tool for deep decarbonization, hydrogen can be deployed to add stability and flexibility to electric grids, thereby enabling the integration of even more renewable power. Hydrogen can also be blended with natural gas to help decarbonize heating and cooling systems, and it can be used in place of fossil energy for hard-to-decarbonize industries such as mining, manufacturing, and steel and cement making.
Hydrogen is already being used in fuel cells for stationary power supply without the noise and emissions of conventional generators, and hydrogen fuel cells are expanding throughout the mobility market to eliminate airborne pollutants from ships, aircraft and locomotives as well as cars and trucks. The element is also set to play a key role in the green chemistry field, partly through its use in producing ammonia.
In short: Global demand for hydrogen is poised to skyrocket.
Cleaning up the hydrogen supply chain
Of course, none of this makes any sense from a climate action perspective under the current state of affairs; although hydrogen is a clean-burning fuel, the global supply of hydrogen drags a long tail of climate impacts and other issues. The vast majority of hydrogen in circulation today is derived from natural gas through a process called steam-methane reforming. In the U.S., natural gas accounts for 95 percent of domestic hydrogen production.
Steam-methane reforming produces large amounts of carbon dioxide, but that is not the only issue that needs to be addressed. Natural gas extraction, storage and transportation are linked to local impacts on habitat, air and water resources as well as fugitive greenhouse gas emissions that escape throughout the supply chain, from the drilling site and on to the transportation, storage and distribution infrastructure.
In past years, these supply chain impacts could perhaps be justified by the benefits of hydrogen as a zero-emission fuel. More recently, though, sophisticated consumers and policymakers have begun to recognize the urgency of addressing habitat and biodiversity conservation hand in glove with decarbonization. Community justice and cultural concerns have also gained attention as manufacturers and other stakeholders adjust their supply chains to the demands of environmentally and socially conscious consumers as well as policymakers.
Black & Veatch addresses those concerns by emphasizing the use of “green” hydrogen produced by electrolysis using renewable energy resources, a process in which an electrical current creates hydrogen gas from water in an electrochemical cell. That process doesn’t make much sense if fossil fuels provide the electricity, but the advent of low-cost wind and solar power has been an absolute game changer.
In addition to the climate advantage of deploying renewable energy, electrolysis systems powered by renewables can be scaled up or down more easily to meet local conditions. That means hydrogen production can be decentralized, which would help relieve pressure to build contentious new gas pipelines. Instead, a nationwide, distributed network of electrolysis facilities could utilize roads and railways for distribution as well as existing pipelines.
Keeping natural gas in play, or not
The green hydrogen field is accelerating beyond expectations, leading Black & Veatch to conclude in its analysis that green hydrogen is a powerful tool in creating an achievable pathway to net zero across numerous “hard to abate” industries.
Realistically, though, it will take years for green hydrogen to push the steam-methane reforming of natural gas to the background. Black & Veatch raises the point that policymakers could support the continued use of natural gas in combination with carbon capture systems, often referred to as “blue” hydrogen production, as a cost-effective means of enabling the supply of hydrogen to keep pace with demand over the near term.
“Some are not convinced that blue hydrogen is a sustainable solution, but the fact is that natural gas will be available well into the foreseeable future for hydrogen production and other uses,” Jonathan Cristiani, an advanced power fuels engineer for Black & Veatch, told TriplePundit. “The carbon capture technology for reducing those emissions is available now, at a scale large enough to make a significant difference.”
More recently, new waste carbon reuse systems and carbon upcycling technologies are beginning to strengthen the economic case for carbon capture to be used in combination with hydrogen production.
However, if carbon capture technologies are source-agnostic, they could also be applied to other, more sustainable sources for natural gas (or methane). After all, hydrogen can be found practically anywhere. The challenge is to focus on resources that are sustainable and cost-effective.
One good example is gas recovery from municipal landfills. Early evidence indicates that landfill gas could provide an economical source for hydrogen production. The focus on hydrogen as a means of extracting value from waste gives rise to other possibilities as well. For example, hydrogen can be extracted directly from agricultural waste and other biomass, or from municipal wastewater, through biological processes that deploy microorganisms to do the heavy lifting.
In addition, researchers are developing systems that extract hydrogen from non-recyclable plastic waste, with carbon nanotubes as a high-value byproduct. Food waste is another area of global concern that could benefit from integration with the hydrogen supply chain.
Next steps for electrolysis
All of this activity indicates that traditional natural gas sources may exit the hydrogen production stage more quickly than anticipated.
Electrolysis with renewable energy is the chief alternative route. The next step is to scale up while minimizing land use issues related to the construction of new wind farms or solar arrays. Water resource issues could also become an obstacle in some regions.
A movement is already afoot to ascend those hurdles: The wind industry is beginning to experiment with combining wind farms and offshore electrolysis systems, which use seawater instead of fresh water to produce green hydrogen to increase the output from wind farms.
If and when the technological obstacles to seawater-sourced hydrogen are surmounted, the result will be a practically limitless supply with little if any impact on land.
That may seem rather pie-in-the-sky, but it wasn’t too long ago that battery-powered cars were confined to the aisles of toy stores and look where we are now.
