Scaling infrastructure to add green hydrogen 

The global push for greenhouse gas reductions has propelled hydrogen - specifically green hydrogen produced from renewable energy sources - into the spotlight. While still in its infancy, the hydrogen economy presents an opportunity for more sustainable transportation, industrial processes and energy production. However, realizing these benefits requires overcoming several infrastructure challenges downstream of its production.

Widespread adoption of green hydrogen will require continued investment in research and development, cross-organizational collaboration regarding production and consumption and robust policy frameworks.

First, existing natural gas infrastructure - including pipelines, storage facilities and transportation networks - must be reworked or replaced to handle hydrogen safely and effectively because of its unique chemical properties. Hydrogen gas molecules are the smallest of any type, rendering them prone to leakage. This necessitates the use of specialized materials and sealing techniques to ensure safe and efficient transportation and storage. Furthermore, hydrogen can weaken materially-incompatible pipeline and vessel structures and the nearly invisible flame upon ignition makes it nearly impossible to spot in the daylight, posing safety risks.

Storage and transportation presents additional logistical complexities. When space is at a premium, either in storage or onboard a vessel for transport, hydrogen's low volumetric energy density compared to natural gas and liquid fossil fuels necessitates extreme conditions - either compression at up to 700 bar (10,500 psi), or liquefaction at temperatures at or below -253° C (-423.4° F). Holding hydrogen in either state is energy-intensive, adding further equipment, energy and cost requirements to long-term storage and transportation.

Addressing the pipeline challenges requires investing in specialized materials resistant to hydrogen embrittlement, while the storage and transportation conundrum compels complicated energy efficiency calculations and decision-making based on numerous variables.

Currently, most hydrogen production relies on extraction from fossil fuels through processes such as steam methane and autothermal reforming. In their simplest forms, these processes produce grey hydrogen, so called because it includes carbon dioxide and other greenhouse gases that undermine the environmental benefits sought from hydrogen. This offgas can be captured - yielding blue hydrogen - but capturing, transporting and storing it is costly.

Green hydrogen production eliminates these issues, but it introduces the need for substantial investments in electrolyzers - typically proton exchange membrane or alkaline type - capacity, grid infrastructure and other ecosystem investments in the balance of the plant. Electrolysis uses electricity to split water molecules into their constituent hydrogen and oxygen components, with the hydrogen harvested and the harmless oxygen gas released to atmosphere or further processed for other industrial uses. When powered by renewable energy sources - such as wind, solar or hydroelectric - the resulting hydrogen is green and sustainable.

Powering the grid with electricity produced from green hydrogen poses some challenges as it requires new energy infrastructure and seamless integration into existing power systems. This integration is becoming increasingly necessary. Populations are turning to smart grids, energy storage solutions and sophisticated energy management systems to balance the growing demand for renewable energy as demands fluctuate in and out of alignment with intermittent supply.

Though hydrogen lags behind traditional fossil fuels in terms of cost per energy unit, its price is expected to decrease in the coming decades. This can be attributed to the evolution of production and usage technologies, public and private infrastructure investments coming to fruition and widespread standardization of safety practices.

Despite these challenges, the green hydrogen economy is compelling because of its net-zero potential. Paired with clean production practices, water vapor can be renewable hydrogen’s only emission, establishing the gas as a crucial component for achieving emissions targets and mitigating climate change.

Moreover, hydrogen can be stored in various forms for extended periods without the energy degradation drawbacks of batteries - at the expense of lower electricity generation efficiency in short-term storage - addressing intermittency issues of direct renewable solar and wind power sources. This stored hydrogen can then be utilized to generate electricity during periods of peak demand, enhancing grid stability and reliability, or to power vehicles or industrial processes. The ability to flexibly store and dispatch renewable energy is a key component for successfully operating renewably-sourced power grids.